Memoirs of the Museum of Victoria 54(2): 271-397 (1994) 31 December 1994 https://doi.org/10.24199/j.mmv.1994.54.13 PHYLOGENY AND BIOGEOGRAPHY OF THE GNATHIIDAE (CRUSTACEA: ISOPODA) WITH DESCRIPTIONS OF NEW GENERA AND SPECIES, MOST FROM SOUTH-EASTERN AUSTRALIA
Brian F. Cohen' and Gary C. B. Poore
Department of Crustacea, Museum of Victoria, 71 Victoria Crescent. Abbotford, Victoria 3067, Australia 1 present address — Department of Zoology, University of Western Australia. Nedlands. WA 6009. Australia
Abstract
Cohen. B.F. and Poore. G.C.B.. 1994. Phylogeny and biogeography of the Gnathiidae (Crustacea: Isopoda) with descriptions of new genera and species, most from south-eastern Australia. Memoirs ol the Museum of Victoria 54 (2): 271-397 The classification of the Gnathiidae is reviewed for the first time since Monod (1926). States of 72 characters are discussed with reference to two outgroups of Flabellifera, forming the basis of a phylogenetic analysis. Ninety-five species are included in the analysis rep- resenting all nominal genera and subgenera and covering the perceived variation in the family. Results indicate that the Gnathiidae can be divided into two principal clades rep- resenting one (Thawnastognathia Monod) and nine genera (Gibbagnathia gen. nov., Para- gnathia Omer-Cooper and Omer-Cooper, Euneognathia Stebbing, Bythognathia Camp, Monodgnathia gen. nov., Bathygnathia Dollfus. Caecognathia Dollfus, Gnathia Leach and Elaphognathia Monod). The new classification differs from that of Monod (1926) in the description of two new genera (Monodgnathia and Gibbagnathia), the revival of another genus previously in syn- onymy (Caecognathia), the elevation of a subgenus to generic rank (Elaphognathia) and the loss of two genera and a subgenus in synonymy (Heterognathia, Akidognathia and Peri- gnathia). The elevation of Elaphognathia to generic rank relies on the recognition of paraphyletic Gnathia. A key to the proposed genera of Gnathiidae is presented. Twenty-five new species are described and figured from south-eastern Australia, three from deep water in the Tasman and Coral Seas, and one from New Zealand. Thawnasto- gnathia is recorded for the first time since 1926. Bathygnathia, Monodgnathia, and Thau- mastognathia are recorded for the first time from Australian waters. Keys to all 45 Australian species are offered with figures of the cephalosomes of the 17 previously described species to aid identification. Habitat and distributional data for all Australian species are presented. The phylogenetic analysis of the family suggests the most significant evolutionary events in the radiation of the family took place in the cold waters of the southern hemisphere. Thawnastognathia, sister group of all other gnathiids, is an endemic genus of four species from the Australian-New Zealand shelf. Gibbagnathia, the second clade, is an endemic, monotypic genus confined to Bass Strait, southern Australia. Paragnalhia is enigmatic in being a single Afro-European species but Euneognathia is a single species from the Antarctic is shelf. None of these four genera has radiated successfully. Bythognathia ( 1 species) from the deep sea (4000 m) of the Caribbean. Monodgnathia (4 species) and Bathognathia (12 species) are both confined to the slope and deep sea. But radiation has been moderate and with the exception of the one species of Bythognathia none is found very deep, unlike many other families of isopods. Two related clades have radiated strongly in more shallow and warmer waters: Caeco- gnathia with 43 species distributed more towards the poles than Gnathia-Elaphognathia (89 species.) which is more cosmopolitan on temperate and tropical shelves and upper slopes. Small clades of species of Caecognathia are confined to Australia. Other species of the highly endemic southern Australian fauna seem to have arisen locally and independently.
Table of Contents
Abstract 271 Introduction 272 Materials 273
271 '
272 BRIAN F. COHEN AND GARY ('. B. I'OORE
Phylogcnetic methods fib Results 283 Biogeography f° -"' Gnathiidac Leach ~"~ Key to genera of Gnathiidae Bathygnathia Dollfus 292 Bythognathia Camp 307 Caecognathia Dollfus 310 Elaphognathia Monod 335 Euneognathia Stebbing 339 Gibbagnathia gen. nov 34~ Gnathia Leach 343 Monodgnathia gen. nov 377 Paragnalhia Omcr-Cooper and Omer-Coopcr 385 Thaumastognathia Monod 385 Acknowledgments 394
Holdich and Introduction temperate waters of the south-east. Harrison (1980) suggested that poor sampling The waters around Australia possess a rich crus- effort, rather than low species diversity, was
1 ; et al., 1 tacean fauna (Barnard, 99 1 Poore 994), responsible for the low number of Australian best documented in the south-eastern temperate species and that further sampling should region where extensive recent research has been uncover more species. This has proved true. completed. The isopod family (jnathiidae is one This paper addresses the fauna of south-eastern of many contributing to this diversity but con- Australia, from near Nowra, New South Wales tains numerous undescribed species. (35°S, 150°E) around Tasmania (43°S) and Gnathiids arc most unusual isopods, poly- across to Pearson Island (34°S, 1 34°E) west of the morphic in the extreme. Males are immediately Spencer Gulf, South Australia. It describes four recognisable by their large forwardly-dircctcd times as many species as were previously known mandibles and five pairs of walking legs. from this region, recognises two new genera, is Females have more reduced jaws and a thorax the first record of Thaumastognathia in over 65 swollen with ovary or eggs. The juveniles, or years, the first records of Bathygnathia and praniza larvae, pass through three instars in the Thaumastognathia from Australia and the first only species studied (Wagele, 1987, 1988), each records of gnathiids from Tasmanian waters. feeding on blood as ectoparasites of fishes. The Four significant Australasian species from out- like female, also with praniza appears a thinner side this region arc also described, all from deep live legs sometimes with guts pairs of and water. It is now apparent that Australia pos- engorged with blood. sesses a rich gnathiid fauna with approximately the The morphology and classification of one-quarter of all the species so far described. Gnathiidac was placed on an excellent footing New species are described and figured. Most by Theodore Monod. Monod's (1926) volume species previously described from Australia of described in detail the anatomy and biology were well illustrated and described by Monod or then the group and illustrated the 62 species later authors. Figures of their cephalosomes further 42 species known. Camp (1988) listed a (Fig. 2) have been copied to aid in identification described since Monod's (1926) work. Eighteen when using the keys. work, species have been described since Camp's As well as describing numerous new species (Table and a two were overlooked by him 1), from Australian coastal, shelf and slope environ- described here. This brings the further 29 are ments we present a new phylogeny and classifi- of described species of Gnathiidae total number cation of the family. This phylogeny is based on reappraisal of the to 155. There has been no a cladistic analysis of 95 described species from since that by Monod relationship of the genera world-wide localities. On the basis of this analy- (1926). sis two new genera are described, one is revived, Prior to this study 17 species of Gnathiidae a subgenus is elevated to generic rank, and other were known from Australia, only six from the genera are lost in synonymy. A key to the ten PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 273
Table 1. Gnathiidae described since 1987 (including two overlooked by Camp, 1988). Species have been reallocated to genus according to the classification scheme adopted in this paper. Each species is followed by its type locality, depth of capture and size of male, when available. Species described prior to this date were listed by Monod (1926) and supplemented by Camp (1988). Coordinates of type localities are those listed by original authors; where size was not stated it was measured from figures.
Bvthognathia vucatanensis Camp, 1988: Yucatan Channel, Caribbean Sea, 21°07.0'-13.0'N, 85°31.5'-32.0'W; 3700-3800 m; 20.8 mm. Caecognathia amakusaensis (Nunomura, 1992): Use, Reihoku-cho, Kumamoto Pref., Japan: 30-35 m; 5.1 mm. Caecognathia kikuchii (Nunomura, 1992): Shiraiwazaki, Reihoku-cho, Kumamoto Pref., Japan; 3.7 mm. Caecognathia saikaiensis (Nunomura, 1992): offTomoezaki, Japan; 3.1 mm. Elaphognathia comigera (Nunomura, 1992): Tujishima Islet, Itsuwa-cho, Kumamoto Pref., Japan; 2.4 mm. Elaphognathia discolor (Nunomura, 1988): Isohara, Kita-ibaragi shi, Ibaragi, Central Japan; 6.2 mm. Elaphognathia wolffi (Miiller, 1989a): Coral Reef near Tiwi, Mombasa, Kenya; 1.6 mm. Gnathia calsi Mulier, 1993b: La Trinite, Anse Riviere. Martinique, French Antilles; 0-2 m; 1.9 mm.
Gnathia cooki Mulier, 1989c: Cooks Bay, Moorea, Society Is; 1 m; 3.7 mm. Gnathia firingae Mulier, 1991: La Reunion L'Ermitage-les-Bains; 0.5-1 m; 2.1 mm. Gnathia gabini Mulier, 1989c: Moorea, Society Is; 0.5 nr, 1.6 mm. Gnathia gonalezi Mulier, 1988: Punta de Betin, Sta Marta, Colombia; 15 m; about 1.5 mm. Gnathia hirayamai Nunomura, 1992: Tomioka, Amakusa, Kumamoto Pref., Japan; 8.5 m; 3.9 mm. Gnathia incana Menzies and George. 1972: Peru-Chile Trench, 1 1°50'S, 77°58'W; 935-907 m; 3.6 mm. Gnathia lacunacapilalis Menzies and George, 1972: Peru-Chile Trench, 07°59'S, 80°37'W; 991-1015 m; 4.5 mm. Gnathia lignophila Mulier, 1993a: Pulau Babi Besar, Tioman Archipelago, Malaysia; lower-intertidal; 1.9-2.9 mm. Gnathia magdalenensis Mulier, 1988: Bahia de Nenguangue, Colombia; 18 m; about 2.7 mm. Gnathia malaysiensis Mulier, 1993a: Pulau Babi Besar, Tioman Archipelago, Malaysia: 1-2 m; 2.3 mm. Gnathia nasuta Nunomura, 1992: offTomoezaki, Kumamoto Pref., Japan; 8.5 m; 3.3 mm. Gnathia nicembola Mulier, 1989b: Entrance channel to Suva Harbour, Fiji; 76-84 m; 2.6 mm. Gnathia samariensis Mulier, 1988: Isla de Morro Grande, Colombia; 30 m; about 1.95 mm. Gnathia vellosa Mulier, 1988: Isla de Morro Grande, Colombia; 25-30 m; about 1.2 mm (excluding pleon).
Conser- world genera now recognised and a checklist of the Marine Studies Group, Ministry for species in the new classification are presented, vation, Melbourne; (BSS) carried Updated keys to the species of Australia are Bass Strait Survey, 1979-1985 Victoria, Melbourne (see offered out by the Museum of Wilson and Poore, 1987 for station locations Materia,s and methods); Australian slope study, 1986, Much of the material on which this study is south-eastern Museum of Victoria, based has come from large benthic surveys of the 1988 carried out by the Poore et al., 1994, for station bavs shelf and slope of southern and eastern Melbourne (see and a discussion ol the diver- Australia- locations, methods Crib Point Benthic Survey, 1965-1972 sity of Isopoda); cruise in the western Coral (CPBS) carried out in Western Port, Victoria, by the 1 986 Cidaris 274 BRIAN F. COHEN AND GARY C. B. POORE
dentate blade mandibular seta
incisor pseudoblade
smooth blade armed carina dorsal lobe
internal lobe basal neck
lamina dentata erisma accessory supraocular lobe superior frontolateral process inferior frontolateral process supraocular lobe mediofrontal process paraocular ornamentation external scissura dorsal sulcus posterior median tubercle frontal border
P1 not reaching lateral margins
anterior constriction (P4) P1 divided into 3 regions
anterolateral lobe (P4)
^areae laterales (P5) median groove (P4)
areae laterales (P5)
dorsal sulcus dorsal sulcus as a thin groove (P5)
lobi laterales (P6) lobi laterales (P6)
pleonite 1 lobuii (P6)
epimera prominent
Figure 1. Stylised male gnathiid (dorsal view) showing main anatomical features.
carried Sea, out by James Cook University of Only males were described because of the dif- North Queensland; and ficulty of identifying praniza stages and females. other material from the collections of the Aus- In the species-rich environment of south-eastern tralian Museum, Sydney and the Museum of Australia, dredge samples with more than one Victoria, Melbourne. species of gnathiid were common, therefore All type material is lodged in the collections of association of females and pranizas with males the Museum of Victoria, Melbourne (NMV), was not considered a sufficient criterion for Australian Museum, Sydney (AM), Queensland identification. No obvious characters were Museum, Brisbane (QM) and New Zealand found that enabled females or pranizas to be Oceanographic Institute, Wellington (NZOI). accurately identified to species and this problem PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 275 was not explored. Identification of females and Gnathiidae. As many species as were practical, pranizas to the species level would be a major rather than the nominal genera, were chosen for project and was not attempted here. the analysis because of doubt about the mono- We follow the anatomical terminology used phyly of some genera. The information on by Monod (1926) and Holdich and Harrison character states comes mostly from illustrations (1980) except for numbering of pereonites and and descriptions in the literature and was sup- pereopods (Fig. 1). The first body segment pos- plemented from specimens in the collections of terior to the cephalon, pereonite 1 (correctly the Museum of Victoria. Published details on thoracomere 2, not pereonite 2 as in Monod's many species were inadequate for this purpose. and Holdich and Harrison's works), is fused to These species were omitted but it is felt that the the cephalon forming a cephalosome. In some 95 species described in sufficient detail covered
species pereonite 1 may be dorsally indis- the range of form seen in the family. Specimens tinguishable from the cephalon. The pylopod of Euncognathia gigas (Beddard, 1886), Para- (pereopod 1) attaches to pereonite 1. Pereonites gnathia formica (Hesse, 1864) and Gnathia 2-6 follow posteriorly with pereonite 2 pos- ma.xillaris (Montagu, 1804) were lent or sessing the most anterior of the five pairs of donated. walking legs. The pereopods are labelled accord- The programs PAUP version 3.1.1 and HEN- ing to the pereonite to which they are attached NIG86 version 1.5 were used to establish (pereopods 2-6). Pereonite 7, when distinguish- relationships between species and to derive a able, is very small and functionally forms part of practical classification which reflected these the outline of the pleon. relationships. The same data set with the same
The scale bar is 1 mm and refers only to draw- assumptions was run under PAUP with the heu- ings of whole animals in dorsal view. Figure ristic search option (general and branch-and-
labels are as follows: Al, A2, antenna 1 and 2; bound) and under HENNIG using />;//* and bb* Iso- PY, pylopod (pereopod 1 ): MP, maxilliped; P2- routines. Outgroups were chosen from the
P6. pereopods 2-6 (walking legs 1 to 5); U, uro- poda Flabellifcra in order to polarise characters.
pods; 1, r, left and right. All illustrations are of The following sections describe the outgroups, the male hoiotype unless otherwise stated. Fig- taxa chosen and character transformations.
ure 1 is of a stylised male gnathiid and is labelled Outgroups to show parts of the animal and its ornamen- Brusca and Wilson's (1991) analysis of the tation. relationships of the lsopoda placed the Gnathii- Monod's ( 1 926) review of the Gnathiidae was dae among the "long-tailed" taxa, part of the extremely detailed and included over 300 refer- non-monophyletic Flabellifcra. They concluded ences. His synonymies were detailed, therefore, that the family no longer deserves the subordinal they are not repeated here in full. Hesse (1864) status traditionally used. Outgroups, therefore, highlighted the similarity of gnathiids to ants were sought from among the Flabellifera. (Formicidae) with the specific name Anceus for- Wagele and Brandt (1988) suggested that the mica. The specific epithets of new species here protognathiid, Protognalhia bathypclagica described are genera of Australasian ants (Tay- (Schultz, 1977) is a "missing link" or intermedi- lor, 1987) chosen only for their euphony, not to ate stage between the Cirolanidae and the Gna- reflect any specific feature of either the isopod or thiidae, and that these two families are closely the ant. All are nouns in apposition. related. Brusca and Wilson (1991) argued that Morphological characters were coded into the Protognalhia is not closely related to the Gna- taxonomic database program DELTA (Dallwitz thiidae but rather Protognathiidac is part of the and Paine, 1986) for all Australian species. Cirolanidae-Anuropidae-cymothoid line. They Descriptions were generated from this program argued that the Cirolanidae is more closely but were heavily edited. The database is avail- related to the Gnathiidae than Protognathiidac able on request by DELTA users from the is to Gnathiidae. Both the Cirolanidae and the Department of Crustacea. Protognathiidae were selected as outgroups.
Eurydice acuticauda Bruce, 1 98 1 was chosen to methods Phylogenetic represent the Cirolanidae for many characters. Hennigian phylogenetic (cladistic) methods Protognalhia bathypclagica is known only were used to generate cladograms as hypotheses from immature specimens; states describing the of the relationship between species of the family sexual characters of adult males arc coded as >76 BRIAN F. COHEN AND GARY C. B. POORE
B
D
K M PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 277
N O Q
Figure 2. Cephalosomes of 17 Australian species of Gnathiidae not described in this work. A, Caecognalhia CtgWiUlsl (Seed). B, C. pustulosa (Hale). C, Gnaihia latidens (Beddard). D, G. calamitosa Monod. E, G. halei Cals. F. G. comma Holdich and Harrison. G, G. meticola Holdich and Harrison, H. G. asperifrons Holdich and
Harrison. I, G.falcipenis Holdich and Harrison. J, G. variobranchia Holdich. K. G. biorbis Holdich and Harrison. L, G. cahnani Monod M. G mulieraria Hale. N, Elaphognathia bifurcilla (Holdich and Harrison). O, E. forceps (Holdich and Harrison). P, E. rimiftons (Holdich and Harrison). Q, E. ferox (Haswell).
Figures copied from original authors except G*. latidens copied from Monod (1926), and G. cahnani and E. ferox copied from Holdich and Harrison (1980).
unknown (? in Table 3). For both outgroups, a oedipus, A. cristatipes, B. affinis. B. magnified, B. number of the mandibular characters were porca and six similar new species provided data. coded as inapplicable due to the difficulty in Akidognathia and Bathygnathia seemed a priori
drawing homologies between the highly modi- to be closely allied and the 1 1 species included fied mandibles of the Gnathiidae and the man- covered the variation within these two genera dibles of other Isopoda. Inapplicable characters and the supposed differences between them, were coded as states separate from those found principally in the form of the pereopods, man- in the Gnathiidae (Table 2). The praniza stage of dibles and frontal border. gnathiid ontogeny was also considered when The remaining species are or could be mem- there was difficulty assessing the plesiomorphic bers of Gnathia and its three subgenera, Gnathia condition of some characters. s.s., Perignathia and Elaphognathia as presently defined. The monotypic subgenus Perignathia Taxa chosen was represented by P. triospathiona although its It proved impossible to include every type species is in doubt (see below). Gnathia s.s. described species of Gnathiidae in the analysis. and Elaphognathia were represented by numer- Many species were excluded because they were ous species. Caecognalhia stygia, type species of not described in sufficient detail to enable com- a genus considered by Monod (1926) a junior plete coding of all character states. Ninety-five synonym of Gnathia was also included. species from all round the world were included (Table 3) representing all nominal genera and subgenera. Character discussion Four species represented the monotypic gen- The 72 characters used in the phylogenetic era Euneognathia (E. gigas), Paragnathia (P. for- analysis are discussed in turn below. All are mica), Heterognathia (H. calva) and Bythogna- potential synapomorphic characters (i.e., none thia (B. yucatanensis). All species of Thaumas- is apomorphic for a single species). The charac- tognathia were included, three of which are ter states are given in Table 2 and the data newly described. Of the remaining genera, Aki- matrix in Table 3. dognathia, Bathygnathia and Gnathia, the type Eyes. Almost all Gnathiidae have sessile, lat- species and all species described in sufficient eral eyes during all stages of development; this detail were included in the analysis. Thus, A. condition is plesiomorphic. Eyes have been lost . .
278 BRIAN F. COHEN AND GARY C. B. POORE
Table 2. Character transformations used in the phylogenetic analysis of 95 species of Gnathiidae. The plesiomorphic state is listed first and separated by ; from the apomorphic state or states. In the
data matrix plesiomorphic states are indicated by and apomorphic states by 1 or more. Characters
with consistency and retention indices of 1 are marked with *.
Eyes Mandible 1. Eyes present; absent. 22. Armed carina inapplicable; absent; present. C ephalon 23. Incisura inapplicable; absent; present; 2. Cephalon broader than long; as long or pronounced. longer than broad. 24. Internal lobe inapplicable; absent; 3. Dorsal sulcus absent; present. present. 4. Paraocular ornamentation absent; 25. Mandible clearly present. less than 5 times as long as wide; 5 times as long or longer. 5. Granules/tubercles absent; present on 26. Apical cusps absent; cephalon; present on cephalon and present. 27. Blade pcreon. dentate/crenulate; not dentate; absent/highly reduced. 6. Cephalon lacking posterior, laterally 28. Pseudoblade absent; present. deflected grooves; grooves present. 29. Setae inapplicable; 7.* Cephalon lacking anterior median absent; present. furrow; furrow present. Antennae 8. Posterior cephalon not divided by 30. Antenna 1 shorter than or equal to shallow grooves; posterior cephalon antenna 2; antenna 1 longer than divided by grooves (often marked with antenna 2. chromatophores). 31. Antenna 1 flagellum with 7 or more Frontal border articles; 6; 5; 4; 3; 2 or fewer articles. 32. Antenna 2 flagellum with 9. Frontal border rounded/produced; 8 or more transverse. articles; 7; 6; 5; 4; 3 or fewer articles.
33.* Antenna 1 peduncle 10. Frontal border not greatly produced; length greater greatly produced. than 4 times width; less than 4 time width. 1 1.* Frontal border not excavated; 34.* excavated. Antenna relatively straight; curved under mandibles. 12. Frontal border without frontal processes; with frontal processes. Pereon
1 3.* Frontal border not clearly delineated; 35. Pereon devoid of or with only few clearly delineated (chalky white setae; setae present anteriorly; setae appearance). present all over. 14.* Buccal cavity wall not visible dorsally; 36. Pereon wide (length <1.85 width); visible beyond rostrum. medium; narrow (>2.5). 15. Entire frontal margin including region 37. Pereon pear-shaped (clearly widest at lateral to the base of mandibles not pereonite 5); not pear-shaped. produced; entire margin produced. 38. Pereon wider than cephalon; narrower 16. Frontal border lacking small median than or as wide as cephalon. indentation; indentation present (not 39. Pereonite 1 clearly extending to to be confused with excavation found margins of pereon; surrounded in Elaphognathia). completely by cephalon and pereonite 17. Setae on frontal border absent; 2; not visible; present. 40. Anterior constriction of pereonite 4 I 8. Mediofrontal process absent; single absent; present. process; multiple processes. 41 Pereonite 4 lacking mid-dorsal spine; 19. Mediofrontal process not inferior; spine present. inferior. 42. Pereonite 6 without lobuii; lobuii 20. Superior frontolatcral process absent; present. present. 43. Posterior margin of pereonite 6 not 2 1 Inferior frontolateral process absent; deeply concave; posterior margin present. deeply concave. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 279
44. Pereonites 5 and 6 not fused; partially 59. External margin inapplicable; devoid fused: completely fused. of plumose setae; a few, well spaced 45. Pereonite 6 lobuii not conical/globular; plumose setae; many setae/dense lobuii conical/globular [see figs 19 22 cover. 40]. 60. Pylopod inapplicable; with many setae 46. Peronite 7 visible dorsally; not visible. on ventral surface (about 15 or more); Pleon, pleotelson and uropods. few setae; no setae. 61. Article 47. Pleotelson short (as wide or wider 2 not circular or conical; conical (see figs than long); medium; long (twice as 21, 24, 36, 42); long or longer than wide). circular. 62. 48. Uropod rami clearly shorter than Spine(s) present on article 3; spines absent. pleotelson; approximately equal to 63.* Ventral length; clearly greater than length of surface setae inapplicable: pleotelson. plumose; simple or absent. 49. Endopod clearly longer than exopod; Pereopods exopod subequal or longer. 64. Pereopod setae plumose; simple or Maxilliped. absent. 65. 50. Mouthparts typical of family; Pereopod setae dense; sparse or absent. small/reduced (difficult to see). 66. Pereopod 4 basis lacking distal 51. Maxilliped of 5 articles; fewer than 5 articles; absent. extension; distal expansion present. 67. Merus of pereopods 3-6 not medially 52. Palp clearly less than 5 times as long expanded along anteroposterior as broad; about 5 times as long as axis; broad. merus expanded. 68.* Pereopod 4 53. Endite with 4 or more coupling hooks; basis lacking a quadratic 1-3 hooks, no hooks. lobe; possessing lobe. 69. Pereopod 4 ischium not expanded; Pylopod ischium expanded; ischium expanded 54. Pylopod pediform/cylindrical; slightly as a cusp. widened; operculate (pylopods 70. Pereopod 5 ischium not expanded; overlapping) ischium expanded. 55. Pylopod of 7 articles; 6; 5; 4; 3 or Pleopods fewer articles. 71. Pleopods setose; not setose. 56.* Pylopod with no articles greatly 72. Appendix masculina inapplicable; enlarged; first article enlarged; second greater than or subequal to length of article; first, third and fourth articles rami; half enlarged. to three-quarters length of rami; absent. 57. Article 3 not reduced; reduced; absent. 58. Aerolae absent; present.
in the adults of only a few species, nearly all of tected (Seed, 1 979). Compared to other Isopoda, which occur in the deep sea (character 1). the mandibles and cephalon of many gnathiids Cephalon. The dorsal surface of the plesio- are strengthened. Apomorphic states of the morphic cephalon is smooth, featureless and cephalon include sculpture and ornaments broader than long, similar to the cephalon of the which may increase the strength of the cephalon; cirolanid, E. acuticauda. While the Cirolanidae these include furrows and depressions and are mostly free-roaming predators or scavengers raised bumps and tubercles. (Bruce, 1986), adult Gnathiidae are cryptic, A peculiar feature found mid-dorsally on the often inhabiting substrate that offers protection. anterior cephalon or rostrum of a few gnathiids Some species may construct burrows. From is a thin translucent region of variable shape and within these hiding places the gnathiid's mandi- size, located above the buccal cavity. The func- bles can protrude to deal with potential trouble tion of this structure and its evolutionary while the remainder of the animal remains pro- importance are unknown. ' II111 11 1 1 11 1 I 1
280 BRIAN F. COHEN AND GARY C. B. POORE
first Tabic 3. Species-character matrix of species of Cinathiidae (95 species by 72 characters). The "?" two taxa are outgroups. Unknown character slates are shown by
100000 00 CirolanWae 000001 .(Mil >0 oooooooooo oooooooooo 4000000000 oooooooooo 0020000010 OOOI Proiognathia IO00O0O00O oooooooooo oooooooooo 100001 1000 00000021 10 0020000000 0000000000 07 01 a atllciTia 01 10000001 000 1007000 0132102020 2710021 101 0100001210 0002220012 0021000010 0072220032 0021101000 02 1 110 II atlnti\ 1 00000000 000 00 1 000 0131 10201 I 2210021 101 0000001 0021000010 00 I 1 1 10 OOO22200I2 II lartttcondyla 1010200001 000 1 00 1 000 0131 102020 2210021 I I 01 0000
0002220021 072 1 00002 02 w magnified 01 1 000000 0001001000 01 12102010 2010021 101 01 10007770 OO0222O02I 0021000021 01 H uedipm I 00000000 oooi 100000 01 12102010 1010021 101 OIOOO022I0
100 1 OKI 02 II I 10 0002220012 002 pixra I |?000000l 0001001000 0131 102010 21 10021 101 0000001 0021000010 01 II liipnuinni 1000000001 0001 1 01000 0112102020 2010021 101 OIOOOOI 2 10 0002220121 i< YoHcnkoviQ 1000000001 0001001000 0131 102010 2210021 101 0000001210 000222002 1 0021001000 02 Syihognaihio ioiooooooi oooooooooo 0I31O02O1O 01 10021 101 0010000210 OOOOI00032 0120001000 01 12 I I 122 212IIOO0O0 I ( . abyx.wrum 0000200001 0000010000 0121001010 32IOOOI I 01 10001210 002241
( agwillisl 000021 1000 0000001000 0121001010 21 101 10001 00020011 10 0012412012 2121000000 02 02 < ukurwnxis 000020000(1 000001 1000 0221000010 31 101 III II 0010000210 0022411777 2121 100000
1 I 10000000 02 ( hiaiu'lifpuiicr,! 0100000000 000000 1 000 Oil 1 00 101 I 2510010010 01 101 01000 012241 1032
I 100000 12 1 1 I 1 I I 1 1 1012 2121 < . i alva 000021 1000 oooooooooo 01 2 1001 010 2 1 00 01 000 10 001241 i can.wltriau I Mil 10200000 000001 1000 0121000010 27IOOI II II 01 1 0000 1 10 0022411 132 2121 100000 01
I I 2I21IOOOOO 72 < ticmtliitiltoih 0070100001 oooooooooo 01 1 1000010 21 1001 101 0010001 10 002241 1732
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< I'hngata OO7O200I0O 0000001000 0121001010 21 10021 101 Oi 10001 110 002741 I 132 2121 100000 12 i i,m/ mi OIIOO2O000O 00000 1 1000 01 2 1001010 321021 I 101 00100012 10 00224 12132 2121 100000 72 i %namphiut'ny> 0000000000 0000001000 01 I 1002010 21 1021 1120 01 10001 110 002241 1131 2121010000 01
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( I I 1 1 ' ifttehymtniopwi 0100000000 0000001000 01 100 101 2410010010 01 10101000 0122411031 10000000 02
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J I ,tillh,)l, ll\l\ 0010200010 1 1 00000 1 00 01 12002020 31 1001 I 120 0000000210 002241 1 132 2121100000 02
I h,i,;;\,,ti 00 1 0000 1 10 1 100000201 0122101010 21 1001 I 101 0000001210 0022412032 2121 100000 72
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I /> I livygaltelta 0000(100010 1 10000121 I I I 12102010 21 10001 I 10 0000000710 002241 1022 2I2IOOOOOO 02 I ramtili'i 0000000010 I ''00000000 01 121 12010 31 10001 120 0100000210 0022412032 2121 100000 02 I \in;ii\liiilliicn\i\ 0O000000I0 ! 100001001 01 12102020 21 1001 I I 1 I 0000001210 0022411032 2121 100000 72 I », / iiih','<;ii,ilhui 001 1 000010 0100000200 I 1320001 10 201001 1110 01 100021 10 001 1200032 0121 100000 02 t,ihh,ii!iiiiihiii 0000200000 010000100! 01 I 1002010 3 30021 I I I I 0010000101 1020300013 0120000000 02 I, hi, a his 001 1000010 I I U 010000121 0121000010 21 1001 101 0000001710 002241 I I 52 2121100000 12 mill, ,iiii 0010000010 I I d 010000121 01 2 000010 71 1001 1101 0000000210 002241 I I 32 2121 100000 02 i4 001 1200010 0100001 I I I 71 I I I I d IIHpOfli HUH 01270001 10 1001 00000001 10 002241 I 132 7121 100000 01 (i 1'fi'mi'fHi'n.ifn 0010200010 010000121 I 0171000010 I 1 1071 I 100 0I10I0II 10 OOI74I 1131 2I2IOOOOOO 02 001 1000010 I I I h cvotii 01000012 I 121000020 571071 I I I 00000002 10 0022411132 2121 100000 "2 i. ,,111,111,1 001 10001 10 I OI220O0OI0 71 10071 I 010000121 101 0000001 10 002 741 I 132 2121 100000 02 (4 i oiiiiuiiIi 01 1 I I I '.'2 n\i\ 1010000010 0000 0121000010 71 1001 I 100 01 10001200 002241 1031 2I2IOOOOOO (i 001 1000010 0100001200 0121000020 2110211 I II t/popoxlruma 0000001210 0022411 I 17 2121 100000 02 t, 1 faicipvnh 001 1010010 01 0000 200 OI220000IO 71 10021 1 1 0000001210 0077411132 2121 100000 02 i 0101 11)111001 c;4 4/i (II 2 I I I 1 1 I i, 00 00000 I 0100001 I I 01 1 1000170 71 I 101 haki 1001 0102001 100 002741 1 137 2121 100000 01 (i I I I 10"2 illcpuhl 001 1200010 01000001 I I 121000020 21 1001 I I 00 100012 10 002241 2121 100000 02 (4 I IIH'I'llhllil 0017200010 010000121 0221000010 21 1001 101 I 0000000210 002241 1777 2121 100000 02 in 00 1 00000 10 OIOOOOI I I I 1 (i tohanna 0177000020 21 107 1 I I I 00100012 10 0(02412132 2121100000 12 1 000010 I I I (> 101 OIOOOOI 1 humiivupilslh 0121000010 21 002 1 101 OIOOOOI 100 0072412032 2121 100000 02 i, 001 I 1 00010 0100001200 ^1 1021 mugtlafcw PHYLOGENY AND BIOGEOGRAPHY OFGNATHIIDAE 281 (/ ttttirgaiitanim 001 1:00010 0100001:11 11:10000:0 3110:11111 0000000200 002241 1 132 : 1:1 100000 (J. DH'tiivltl 00 1 00001 10 1 0000 1 00 01:1000010 11 1001 1001 0000001200 002241 1032 : i : 1 1 00000 02 (J. lliorlfil.li'ni oo?o:ooo 1 1 0000 1 101 0122000010 : 1 1 00 1 1 00 0100000210 00224 11??2 2121100000 02 (J, tnufimtrfa 0010000110 1 0000 1 1 1 I 0122000010 2110021101 O00O000I 10 0022411132 2121100000 02 (». myxiritun 001 1 0000 10 0100001211 1 1:10000:0 2110011 1:1 0000001 no 002241 I 132 2121100000 01 O Hki'inMa 0010000010 1 0000 1111 1 1:10000:0 31 1001 1 101 0010001 I 10 002241 1032 2121100000 72 (i, runo.sTi.wna 001 1000010 0100001:00 0122000(20 2110011 ill 0000000110 002241 1132 21211 00000 01 <>' othmtoinachito 0010000010 0100001111 01:10000:0 2110:11101 0000000100 0022411 132 21211 00000 01 (i- iantoth'in'tx 0010000010 1 0000 1 200 01:1000010 31 10:01 121 0000001200 00224 11132 21:11 00000 72 ii scmilalitnms 0001:00010 0100001:1 11:1 1 1 I I 000 ??100l 111 01 1 000 1 10 0022411732 : 1 : 1 1 00000 02 (i slii;i>uiciv\ 00 1 1 1 0000 1 01 0000 101 01 1 10010:0 : 1 1 002 1 1 1 0000010210 01 1241 1012 :i:i 100000 02 Li. ll'losiHilhioiiti 00000000 1 0100000100 11:1 00 1010 20100:0011 0000001 1 10 0772410032 11711 00000 02 (i wiiinhraiuliiii 00 1 00000 10 1 0000 1 00 01:10000:0 2110211011 0000000110 0022411032 : 1 : 1 1 00000 02 (, wlltna 0010:00010 1 0000 01:1 1 1 200 0000 31 10201 121 0000001:00 0022411132 : 1 : 1 1 00000 (i tvirmid 1 001 0000 10 I I I 1 0100001 1:10001:0 2 1 1 002 1121 0100001700 002241 1732 21 2 1000000 V. xirxmalh 0010:00010 1 0000 1 200 01:1000010 31 10211121 0000000: 1 0022412132 21:11 00000 (j rtira.\ 00000000 1 I 0100001 I I 11:1 0000 1 21 I0():i I 11 0000001 I 10 0022412032 2121 100000 1/ lyhbstntma 1 01001000 0010101000 1 01 1001010 : 1100:1 111 01000001 10 00022201 1 I 0021000120 \l 1010000000 cmtatl/HH 0070000000 I 1 01 100 010 :i 100:1 101 01 10000:10 0002220012 002 1 000 1 2 \I poncra 1010000000 0010000000 01:1001010 201002101 01 0000 1 1 10 000:22001 I 002 1 000 1 :o I'liruvntilhhi 0010000000 0000001000 1 1 01:1 0000 30100:1 1 0010000:10 0011 13001: 01:0100000 1 .In cms 0000:00000 I 0000001000 0:: 100001 2501000010 00000101 1 1020300013 01:11 00000 I metephaiw 0000000010 1 1 1 1 0100001:00 0000: 4M)I000010 000 10 1000 20202000 1 0121 100000 I owtognalhu* 0000000001 1 1 0000001000 1 0000: 44010101 10 000:010:01 I0:03000 1 0121100000 I Muwmmmn 0000000010 0000001000 0131 0000: 540 1 2000 1 0O010101 1 2020300013 0121100000 Characters 2-8 summarise character changes Mandibles. Pronounced, anteriorly protrud- in the cephalon. ing mandibles characterise the adult male Gna- Frontal border. The frontal borders of the thiidae. These mandibles are believed to be for Gnathiidac are variable and often complex. display or defence and not involved in feeding Monod (1926) introduced terms to describe (Brusca and Iverson, 1985). Male Gnathia have many of the unique structures found there (see been observed capturing females with its man- fig. 1 ). The plesiomorphic frontal border is dibles to gather a harem in its burrow. Homo- simple, smoothly rounded, only slightly pro- logies between the mandibles of gnathiids and of duced and devoid of setae, similar to that of other isopods are difficult to draw. The molar, most cirolanids. The apomorphic frontal border spine row and lacinia mobilis are reduced if may have one or more frontal processes originat- present. The mandibular palp may be represen- ing from different vertical levels and may be ted by the mandibular seta in gnathiids but this greatly produced or deeply excavated. is not assumed. Gnathiids belonging to the Section Transver- For the purposes of this analysis, the plesio- sae (see Monod. 1 926) possess a relatively linear morphic state of the mandibles in gnathiids is of frontal border which is punctuated with one or a relatively straight and symmetrical mandible more frontal processes. All species of lialhygna- with a single dentate blade, homologous to the thia lack frontal processes but possess a frontal lacinia mobilis of cirolanids. Monod (1926) border produced into a rostrum. The rostrum introduced new terms to describe what are can be as long as the rest of the cephalon beyond believed to be features unique to the gnathiid which the buccal cavity wall may be visible. The mandible. No homologies are drawn between frontal border of Elaphognaihia has been deeply the internal lobe and molar process of the man- excavated. The frontal border region of some dible of other Isopoda and the armed carina and species of Monodgnathia is clearly delineated incisura of gnathiids and the incisor process of from the rest of the cephalon and has a chalky- other isopods. These characters have been coded white appearance in the two newly described as inapplicable for the outgroups. Other apo- Australian species. morphic states include the dramatic lengthening 2*: BRIAN F. COM UN AND GARY C. B. POORE ofthe mandibles and addition of apical cusps as Characters 47-49 summarise these changes. (bund in Elaphognathia. Maxilliped. The plcsiomorphic maxilliped is Characters 22-29 summarise character 5-articled with a palp approximately two to changes in the mandibles. three times as long as broad. The maxilliped is Antennae. The antennae are similar to the similar in most gnathiids; apomorphic changes antennae of other Isopoda: antenna I with a 3- include the loss of some or all of the coupling articled peduncle and a short first llagella article; hooks found on the internal margin of the endite antenna 2 with a 5-arlicled peduncle. The first and the lengthening of the palp to approximately article ofantenna 2 is very short and not figured five limes its width. in gnathiid illustrations. Reduction in the num- The exceptions are the genera 1'haumastogna- ber of antennal llagella articles, reduction in l/iia and Gibbagnathia whose maxillipeds are width of the peduncle of antenna L, and greatly reduced to only one or two articles or lost reduction in the length of antenna 2 (relative to altogether (characters 50-53). antenna I) are all apomorphic states. Pylopod. The pylopod is the highly modified Characters 30-34 refer to the antennae. percopod 1 and defines the Gnathiidac. The Pereon. The Gnathiidac differ considerably pylopod is directed anteriorly and forms the from the body plan of Cirolanidae. Many gna- most ventral moulhpart. The function of the tliiids have a more elongate and flexible habitus; pylopod has not been fully investigated but it has are proportionally narrower and longer, and are been suggested that in most genera it acts as a better articulated between pereonites 3 and 4 operculatc cover for the other mouthparts (characters 36-38 and 40). and/or as a large surface area across which gas Cephalisation is characteristic of the Gnathii- exchange takes place (Seed, 1979). An analogue dac, pereonitc I is partially fused with the cepha- is seen in the third maxilliped of decapods. lon in all species. Further cephalisation has The plcsiomorphic state of the pylopod, a in occurred a few species; pereonitc I has simple pereopod, is seen in the "gnathopode" of become immersed or completely fused with the the larval Paragnathia formica (Monod, 1926: cephalon (character 39). Pereonitc 7 is reduced fig. 34). In adult males of all genera except and appears to form part of the pleon. In a few Bythognathia the pylopod is simplified and species, pereonitc 7 is not visible dorsally. Vari- lacks the terminal unguis. The apomorphic ous ornamental changes of unknown function states involve a reduction in the number of have also occurred and are summarised in articles from more than five to as few as three or characters 41-43 and 45. These changes may two, a change from a cylindrical shape to an serve to strengthen the pereon which is relatively operculatc shape and the loss of setae. The fringe soft, especially in the pranizas and females. of plumose setae seen on the external margin of Pereonites 5 and 6 of pranizas have been com- article I on the pylopod of many species has pletely fused together into an clastic stomach been secondarily derived and is not directly region (Wagcle, 1987). Pranizas are able to homologous with any setae on a typical pereo- engorge themselves on their fish host (Paperna pod. This condition is apomorphic. and Por. 1977; Wagcle, 1987) and this elastic Characters 54-63 are changes in the pylo- stomach region expands and contracts with the pod. meal. A few adult gnathiids retain this apomor- Pereopods. Adult gnathiids have only five phy (character 44). pairs of functional walking legs: thoracopods 3- Pleon, pleoteison am/ ttropods. The tailfan is 7 or pereopods 2-6 of other isopods. Percopod 1 longer and more slender than the tailfan of Ciro- has been modified into the pylopod and perco- lanidae (Wagcle. 1987). This may aid in loco- pod 7 is absent, a neotenous state shown in all motion, particularly for the praniza which must isopod mancas (first instar). The five remaining swim to and from suitable fish hosts. The pleo- pereopods (2-6 in our numbering) primitively teison of most gnathiids is triangular with a are very similar to each other and to the pereo- marked apex (though the truncated pleoteison of pods ofother isopods except for a dense covering C. agwiHi.si (Seed) is a notable exception). The of plumose setae. Pranizas use these plumose uropodal rami of Cirolanidae are short, shorter setae to swim towards a suitable fish host than or about as long as the pleoteison. (Wagcle and Brandt, 1988). Elongation of the rami relative to the pleoteison The proportions of the basis, ischium and and of the exopod relative to the endopod are merus on pereopods 4-6 are diagnostic of considered apomorphies. species of Balhygnal'hi a and Monodgnalhici. The PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 283 merus of pereopods 4-6 in some species of saved represent only a fraction of the true num- Balhygnathia is medially expanded along the ber of equally parsimonious trees for this data anteroposterior axis. The ischium of pereopod 4 set. Because of the large number of equally par- of species of both Monodgnathia and Bathygna- simonious trees found it was necessary to calcu- thia may be distally expanded, occasionally as a late consensus trees with their resulting loss of circular cusp which appears to function as a large information and resolution. Nelson strict-con- foot or support. The distal articles below the sensus and 50% majority-rule trees were gener- ischium cusp can be directed along the same ated. These differed from each other only at the plain as the ventral face of the cusp further subgencric level, the major clades which could increasing the surface area available for support; be used to define genera were identical in both. these articles no longer appear to be part of a Numerous versions and subsets of the data functional walking leg (sec Monodgnathia pon- matrix supported the major clades, therefore, we era). The ischium of pereopod 5 may also be arc confident of the monophyly of these major expanded. The basis of pereopod 4 of some clades. The strict consensus tree is shown in fig. species previously assigned to Akidognathia has 3. Two major clades are evident. The smaller developed a pronounced quadratic lobe on the clade is comprised solely of the genus ihaumas- lateral face (see tigs 74 and 76). The function of tognathia: the other clade contains the remain- this structure has not been investigated though it ing nine genera. appears to be capable of locking pereopod 4 Ten characters (14%) retained ci and ri equal * against the pereon. to 1 and are marked with in Table 2. A further Characters 64-70 explain changes in pereo- 15 characters (21%) had ci equal to or greater pods. than 0.5. Pieopods and penes. The pleopods are useful The transformation series, apomorphic taxonomic characters for the study of many changes at all nodes of the cladogram, were crustacean taxa but do not vary greatly among investigated using the apolisl option in PAUP species of Cinathiidae. The plesiomorphic pleo- and the program CLA.DOS. Ambivalent charac- pods have setose margins (e.g.. Cirolanidae) and ters were revealed with the v.v // option in HEN- the appendix masculina is as long or longer than NIG86. Thirty-two characters were ambivalent the endopod of pleopod 2. Loss of setae from the at one or more nodes; 18 occurred at nodes that pleopodal rami (character 71) and reduction separated the major clades. The implication of (character 72, state 1) or loss (state 2) of the this is that these characters could not be used in appendix masculina are apomorphic states. The defining genera unless post hoc decisions on penes of most gnathiids are small: only in a few their value were made. species are they greatly enlarged. The successive weighting option (PAUP reweight) resulted in longer equally parsimoni- Results ous trees (after weights had been reconverted to unity). These trees resolved some clades, princi- Cladogram pally within the Caeeognalhia and Gnathia While processing earlier versions of the data clades, suggesting that a more robust analysis matrix using the programs PAUP and FIENN1G may reveal that these two genera can be further it was not uncommon for one program to find divided and refined. Because of their greater shorter trees than the other. Neither program length, trees generated by the successive weight consistently found the shorter trees, therefore, option were not considered further. when dealing with large data sets we strongly rec- ommend that more than one tree-calculating Character changes defining clades and genera program is used. Character changes defining the major clades For the final data matrix (Table 2) both HEN- are discussed below. The major clades for which NIG, using the mh* and bb* search options, and taxonomic status exists or is proposed are out- PAUP, using the heuristic search option, found lined and discussed in further detail. No con- - equally parsimonious trees of the same length clusion is drawn about the relationship of the 594 steps (consistency index = 0.19, retention Cinathiidae to the outgroups. index = 0.63). The family is divided into two clades, I and Almost 1000 equally parsimonious trees were 16, interpreted as one and nine genera respect- saved by HENNIG and 3000 trees by PAUP but ively. given the limited memory available on the com- I'hamnastoganthia (clade 1 ) shares the follow- puters used for the analysis, the number of trees ing apomorphies that are never reversed: 284 BRIAN F. COHEN AND GARY C. B. POORE 8 I c i| S c 3^-K^o U X goo ft £ "o £ -Cc 5b Oi Q. O p C I j3 0) "> £ m 3 0.25*5 oJSJSS^o, CHI Is S PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 285 '" O OkJ 0,3 £ c 1 -QlU u 0) nl3 8 nj 0) (o c S w +>r w Cfl P „; 3 mt P 01- u §5£riI§«III§£*aS8t 5»S S o £ oi w . D ca -i ACQ a^« s g i (D Figure 3. Strict consenus tree calculated from over 3000 equally parsimonious trees (The tree does not indicate branch length but is organised for clarity only). mouthparts small; maxilliped of fewer than 5 Gibbagnathia (clade 2) is a monotypic genus articles; antenna curved under mandibles; defined by numerous autapomorphies not antenna 1 longer than antenna 2, antenna 2 ped- included in this analysis (see Methods). In this uncle stout (less than 4 times width) and flagel- analysis Gibbagnathia is characterised by the lum of 3 articles or less; pereonite 7 not visible following apomophies convergent in other taxa: dorsally and pleopods without setae. The follow- mouthparts small; pylopod pediform; maxilli- ing plesiomorphies also unite Thaumastogna- ped of fewer than 5 articles; frontal border with thia: pylopod pediform, not operculate and processes; superior frontolateral process pres- pereon widest at pereonite 5. ent; mandibular blade reduced or absent and Clade 16 {Gibbagnathia, Paragnathia, Eun- cephalon and pereon covered with numerous eognathia, Bythognathia, Monodgnathia, Bathy- granules and setae. gnathia, Caecognathia, Gnathia and Elaphogna- Clade 15 unites eight genera which share thia) share the following characters that are the following characters that are sometimes sometimes reversed: antenna 1 flagellum of four reversed: mouthparts not reduced; pylopod not or more articles; pereon even-sided; pereonite 4 pediform, with setae on ventral surface; maxil- possessing an anterior constriction; pereonite 7 liped of 5 articles (sometimes with coupling visible and antenna 2 longer than or subequal to hooks); antenna 1 peduncle length greater than antenna 1. four times width and dorsal sulcus present. 286 BRIAN F. COHEN AND GARY C. B. POORE of the pylopod. These Paragnathia (clade 3) is also a monotypic marily on the structure pylopod 5- genus defined by numerous autapomorphics not two genera share synapomorphics: pylopod article 2 greatly included in this analysis (see Monod, 1926). In articled, operculate; present on article 3. Mon- this analysis Paragnathia is characterised by the enlarged with spine(s) defined by synap- following which are convergent in other taxa: odgnathia (clade 6) is further blade present; pereopod pylopod 6-articled, operculate (articles 1, 3 and omorphics: mandibular ischium dis- 4 enlarged); frontal border without processes; 4 basis with a lateral quadratic lobe, and frontal pleopods without setae; pereopods covered in tally expanded into a circular cusp Australian plumose setae and uropodal rami clearly extend- border as a distinct (chalky white in (clade is ing beyond the apex of the pleotelson. species) region. Bathygnathia 7) apomor- Clade 14 unites seven genera with the follow- defined by one synapomorphy and two buccal cavity ing synapomorphics that are sometimes phies convergent in other taxa: border reversed: pylopod of 5 or fewer articles (except wall protruding beyond rostrum, frontal Bythognathia) and external margin of pylopod greatly produced and the presence of setae on the reversed in with at least a few setae. frontal border. Other apomorphies long (length Euneognalhia (clade 4) is a monotypic genus some species include: mandibles with lat- defined in this analysis by the following apomo- about 5 times width); pereopods 3-6 per- phies convergent in other taxa: pylopod 5- erally expanded merus and the ischium of articlcd (not operculate), with a dense margin of eopod 4 expanded distally (though not necess- plumose setae; frontal border transverse, with arily as a circular cusp). processes; mediofrontal process with multiple Clade 12, comprising Caecognathia and Gna- projections; inferior lateral process present; thia. is defined by three apomorphies, all of mandibles with a pseudoblade and an internal which involve the pylopod: pylopod 2- or 3- reduced. lobe; cephalon with paraocular ornamentation; articled, article 1 enlarged and article 3 and posterior border of pereonite 6 deeply con- Other apomorphic character changes that are cave with lobuii. For a complete description, reversed in some species include: pylopod with including autapomorphics not used in this dense margin of plumose setae and article 2 of analysis sec Monod (1926). pylopod circular. Caecognathia (clade 8) is Clade 13 unites the seven remaining genera defined by three apomorphies reversed in some which possess an operculate pylopod (except species: a rounded frontal border; a mandibular Bylhugnalhia). blade which is not dentate or crenulate (reversed in P. and pleopods without Clade 1 1 links three genera Bythognathia, crcmilatifrons) Monodgnathia and Bathygnaihia who share setae. three apomophies, never reversed: produced Clade 9 is characterised by two non-reversed frontal border; absence of a dentate mandibular apomorphies of the frontal border: frontal bor- blade and presence of four or more coupling der transverse and with processes. Two other hooks on the maxillipedal endite. Other charac- apomorphies are reversed in some species: the ter changes are reversed in some species or gen- presence of a superior frontolateral process and era. These include: absence of eyes (present in a mandibular incisor. This clade contains 56 two species of Bathygnaihia) and appendix mas- species previously allocated to Gnathia and Ela- culina one-half to three-quarters length of the phognathia. pleopodal endopod. Bythognathia (clade 5), the Our analysis did not result in further dichot- least derived genus, is monotypic and defined by omies between major clades. The species G. numerous autapomorphies (Camp, 1988 for triospathiona Boone, which Monod (1926) complete description). Bythognathia is defined placed in the subgenus he incorrectly called Per- in this analysis by the following apomorphics ignathia, was not significantly different from convergent in other taxa: antenna 1 flagellum 7- other species of Gnathia. Nine species belonging articled; uropodal rami clearly extending to the subgenus Elaphognathia did cluster in a beyond the apex of pleotelson; pylopod 6- monophylctic clade sharing several synapomor- articled. pediform, external margin with dense phics: frontal border excavated, mandibles pos- cover of plumose setae; pereonite I extending to sessing an internal lobe and lacking a dentate lateral margins of pereon; pereopods with dense blade. Other character changes are reversed in cover of plumose setae and pereopods 3-6 with some species: mediofrontal process and man- laterally expanded merus. dibular seta absent. Recognition of this taxon Monodgnathia and Bathygnaihia form a relies on recognition of a paraphyletic nominal strong and consistent group (clade 10) based pri- taxon Gnathia. Elaphognathia. with its deeply . PHYLOGENY AND BIOGEOGRAPHY OF GNATH1IDAE 287 excavated frontal border, is immediately dis- Amar and Roman, 1 974 with Caecognathia (see tinguishable from Gnathia, therefore, both Ela- Wagele, 1987). phognathia and Gnathia are given generic Table 4 lists all currently known species in the status. new classification. A new classification Gnathiidae of Biogeography Monod (1926) in his major revision of the Gnathiidae recognised six genera: Akidogna- The family Gnathiidae is widespread, found thia. Thawnastognathia, Paragnathia, Euneog- from the Arctic through to the Antarctic and the nathia, Balhygnathia and Gnathia. The genus intertidal, shelf and upper slopes of the major Gnathia was further divided into three subgen- oceans. The South Atlantic, Indian Ocean and era: Gnathia, Elaphognathia and '"Perignathia". the Eastern Pacific Ocean have yielded few Since then, Bythognathia was erected by Camp species of Gnathiidae compared to the seas (1988). Of these genera and subgenera Euneo- around Europe, the Caribbean and the Western gnathia, Bythognathia, Paragnathia and Thau- Pacific. Whether this reflects the amount of mastognathia remain as originally defined but a taxonomic work undertaken in the various new classification is needed for the others. regions or a natural pattern is unclear, though The strict-consensus tree, the most conserva- there is no a priori reason to expect the Pacific tive consensus tree, gives a good deal of confi- and Indian Oceans to possess a less diverse gna- dence in the robustness of the clades and is used thiid fauna. as an hypothesis on which to base a new classi- The cladogram contains information about fication as follows: the evolution of the family. The most significant evolutionary events in the radiation of the Gna- Family Gnathiidae Leach, 1814 thiidae took place in the cold and cool waters of Bathygnathia Dollfus, 1901 the southern hemisphere. Thaumastognathia, Bythognathia Camp, 1988 four species on the shelf of Australia-New Zeal- Caecognathia Dollfus, 1901 and, is the sister group of all other gnathiids. Its Elaphognathia Monod, 1 926 presence on coasts on both sides of the Tasman Euneognathia Stebbing. 1 893 Sea indicates that the genus is at least 80 million Gibbagnathia gen. nov years old, the time usually given for the separ- Gnathia Leach, 1814 ation of these two land masses. The monotypic Monodgnathia gen. nov. Gibbagnathia, the second clade in the cladogram Paragnathia Omer-Cooper and is also a southern Australian shelf species. Omer-Cooper, 1916 Paragnathia is enigmatic in being a single Afro- Thaumastognathia Monod. 1926 European species but Euneognathia is a single The significant taxonomic changes proposed species from the Antarctic shelf. by this classification are: None of these four genera has radiated suc- 1 Synonymy of the genus Akidognathia Steb- cessfully. But the next clade of three genera has bing, 1913 with Bathygnathia as a result of its begun to radiate in cold water. Bythognathia type species being placed in the clade containing (one species) is from the deep sea (4000 m) of the all species of Bathygnathia. Caribbean. Monodgnathia (four species) and 2. Erection of a new genus Monodgnathia to Bathognathia (12 species) are both confined to house non-type members of the former genus the slope and deep sea (245-2698 m). Monodg- Akidognathia. nathia has a very disjointed distribution 3. Erection of a new genus (presently mono- between the Western Pacific and North Atlantic typic) Gibbagnathia. suggesting that further species await discovery. 4. Resurrection of the genus Caecognathia But radiation has been moderate and with the based largelv on the Section Productae of Gna- exception of the one species of Bythognathia thia (Monod, 1 926). none is found very deep, unlike many other fam- 5. Restriction and redefinition of the genus ilies of isopods. Gnathia as a paraphyletic taxon. Two related clades have radiated strongly in 6. Elevation of the subgenus Elaphognathia to more shallow and warmer waters: Caecognathia generic status on the basis of monophyly. with 43 species distributed more towards the 7. Synonymy of the subgenus Perignalhia poles than Gnathia-Elaphognathia (89 species) Monod, 1926 with Caecognathia. which is more cosmopolitan on temperate and 8. Synonymy of the genus Helerognathia tropical shelves and upper slopes. Elaphogna- ) IKK BRIAN I . COHEN AND GARY C. B. POORE Table 4. Species of Cinathiiclac assigned to genera according to the new classification proposed here. See Monod (1926) for full synonymies of species published by him or prior to this date. Later authorities are included in the References. Bathygnathta Dollfus, 1901 ('. saikaiensis (Nunomura, 1992) is. adlerzia sp. nov. ('. sanctaecrucis (Schultz, 1966) II. Birstein, 1963 1 1 qffiniS c '. schistifions (Stebbing, 9 3) ft bathybia (Beddard, 1886) C. .v<7-ra/tf (Richardson, 1909) is. cardiocondyla sp. nov. C stygia (Sars, 1877) //. CUrvirOSttis Richardson, 1909 c '. traehymesopus sp. nov. li. 1977 magnifies Moreira, C vanhoeffeni (Menzies, 1 962c) ft monodi Cals, 1974 C, vemae (Menzies, 1962a) II Oedipus (Stebbing, 1913) ('. wagneri (Monod, 1925a) ft porca Kensley, 1980 Elaphognathia Monod, 1926 ft segonzaci {Cals, 1982) I',, amboinensis (Cals, 1978) H tapinoma sp. nov. /;. bacescoi (Bacescaj, i960) II vollenhovia sp. nov. /•:. bifurcilla (Holdich and Harrison, 1980) ( Bythognathia 'amp, 1988 /•.'. cornigera (Nunomura, 1992) /^ yucatanensis Camp, 1988 E. discolor (Nunomura, 1988) A'. ,/<7vm (Haswell, 1884) Caecognathia Dollfus 901 £, forceps (Holdich and Harrison, 1980) c ' abyssorum (Sars, 1872) /'.'. froygattella sp. nov. C agwillisi (Seed, 1979) E. insolita (Stebbing, 1905) C akaroensis (Monod, 1926) /.'. lucanoides (Monod, 1926) C. albescenotdes (Menzies, 1962a) /.'. monodi (Gurjanova, 1936) C amakusaensis (Nunomura, 1992) /•.. rangifer (Monod, 1926) C antarctica (Studer, 1883) ( /.'. rimifions (Holdich and Harrison, 1980) '. bicolor (Hansen, 1916) /;'. SUgashimaensis (Nunomura, 1981) C branchyponera sp. nov. /:. iw///,(Muller, 1989a) ( '. ((/err/ (Richardson, 191 I C ca/va (Vanhdffen, 1914) Euneognathia Stebbing, 1893 C. consobrina (Monod, 1926) E, gigas (Beddard, 1886) C coralliophila (Monod, 1926) C crenuiatifrons (Monod, 1926) Gibbagnathia gen. nov. (i. nov. c europalothrix sp. '. diacamma sp. nov. £ '. dolichoderus sp. nov. Gnathia Leach, 1814 C elongata (Krflyer, 1847) (/ afiicana. Barnard, 1914 C floridensis (Menzies and Kruczynski (7. albescens Hansen, 1916 1983) G. alecs Monod, 1926 -/'/;/ C !,' G.falcipenis Holdich and Harrison, 1980 G. rectifrons Gurjandva, 1933 G.fallax Monod. 1926 G. rhytidoponera sp. nov. £?» firingae Muller, 1991 6'. samariensis Muller, 1988 G. gonalezi Muller, 1988 G. schmidti Gurjanova, 1933 G. haleiCak. 1973 G. serndatifrons Monod, 1926 G. hirayamai Nunomura, 1992 G. steveni Menzies, 1962b G. illepida Monod, 1923 G. stigmacros sp. nov. G. incana Menzies and George, 1972 G. taprobansis Monod, 1926 G. inopinata Monod, 1925b G. teisseri Cals, 1972 G. iridomynncx sp. nov. G'. tridens Menzies and Barnard, 1959 G. Johanna Monod, 1926 G. trilobata Schultz, 1966 G. lacunacapi talis Menzies and George. 1972 G. trio.spalhiona Boone, 1918 G. latidens (Beddard, 1886) G'. tubcrcu/ata Richardson, 1910 G. lignophila Muller, 1993a G. tuberculosa (Beddard, 1886) G. magdalenensis Muller, 1988 G. variobranchia Holdich and Harrison, 1980 G. malaysiensis Muller, 1993a G. vellosa Muller, 1988 G. margaritarum Monod. 1926 G. venusta Monod, 1925b G. maxillaris (Montagu. 1 804) G. virginalis Monod, 1926 G. meticola Holdich and Harrison. 1980 G. vorax (Lucas, 1849) G. mortenseni Monod, 1926 G. midieraria Hale. 1924 Monodgnctthia gen. nov. M. colobostruma sp. nov. G. mystrium sp. nov. M. cristatipes (Stebbing, 1913) G. nicembola Muller, 1 989b M. ponera sp. nov. G. notostigma sp. nov. M. poteriophora (Monod, 1926) G. odontomachus sp. nov. G. oxyuraea (Lilljeborg, 1855) Paragnathia G. panousei Daguerre de Hureaux, 1971 Omer-Cooper and Omer-Coopcr, 1916 G. phalkmajopsis Monod. 1925b Paragnathia formica (Hesse, 1864) G. philogona Monod, 1926 Thaumastognalhia Monod, 1926 G. pisciwra Paperna and Por, 1977 T. diceros Monod, 1926 G. productatridens Menzies and Barnard, 1959 T. metaphonc sp. nov. G. prolasius sp. nov. T. oreclognathus sp. nov. G. puertohcensis Menzies and Glvnn, 1968 T. wa.smannia sp. nov. G'. rathi Kensley, 1 984 thia is confined to the Indo-West Pacific region Though only limited areas of the Australian except for one species, E. bacescoi, which is from coastline have been sampled, it is still clear that the Mediterranean. Most species of Elaphogna- the continent possesses an extremely rich and thia are confined to warm waters. diverse gnathiid fauna in intertidal, shelf and Holdich and Harrison (1980) suggested that slope environments (Table 5). About one quar- more Australian species of Gnathiidae would be ter of all the presently described species of Gna- discovered once detailed surveys were com- thiidae are found in Australian waters. All but pleted in regions which had yet to be investi- three monotypic genera (Bythognathia, Euneog- gated. Sampling of the Australian coast, shelf nathia and Paragnathia) are represented. and slope has yielded 28 new species of Gnathii- 1 Cals ( 973) and Holdich and Harrison ( 1 980) dae, more than doubling the number of argued that it was premature to state that Aus- described Australian species to 45, of these 34 tralia has an endemic fauna but it now seems are found in the south-east. To date, only a few certain that this is true for at least southern Aus- areas of northern Australia and no areas in the tralia. The northern boundary along the eastern south-west have been intensively surveyed. coast and the western boundary of all species are Even in regions where detailed work has been uncertain because of absence of sampling but carried out not all the potential habitats have there is little overlap between this fauna and the been fully investigated. Further sampling is fauna of tropical Australia recorded by Holdich bound to yield more species of Gnathiidae. and Harrison. G. calmani, described from Vic- 290 BRIAN F. COHEN AND GARY C. B. POORE Table 5. Habitat and distributional data for Australian Gnathiidae following format of Holdich and Harrison (1980: table 1) and incorporating new species and range extensions for previously described species from collections of the Museum of Victoria. Species Substratum Depth (m) Locality Bathyxnattiia aldcrzia sp. nov. 780-795 NW Coral Sea B. carilioamdyla sp. nov. silt to clav 868-1730 Off Freycinet Peninsula, Tas. and off Terrigal, NSW B oplsthapah sp. nov. 2632-2698 E of Newcastle, NSW B. roltenhovia sp. nov. coarse shelly sand 800 47 km S of Cape Conran. Vic. and W coast of South Island, New Zealand Cttnvgaathia agwillisf (Seed, 1979) tubes of Rhampobrachium sp. intertidal Aireys Inlet. Vic. and Elliston, SA and colonies of Galeolaria sp. ( '. brancbyponcra sp. nov. muddy coarse shell with many 400-426 Nowra, NSW to Point Hicks, Vic. sponges C diacamma sp. nov. fine to coarse sand 1 5- 1 03 Western Bass Strait and S of Newcastle, NSW ( . dolichodcnis sp. nov. fine to muddv sand 110-130 Eastern Bass Strait and E of Cape Banks, NSW C gHmnptogenys sp. nov. 1000 S of Point Hicks. Vic. C. hubcria nov. sp. mud. sand and hard bottom and 27-185 Bass Strait and Broken Bay, NSW sponges C. Icptanillu sp. nov. sand and shell 22-800 Bass Strait, E coast of Tas. and E of Sydney, NSW C. parutrcchia sp. nov. shaded, sessile invertebrates 20 Pearson I.. SA C. pusudosa (Hale. 1924) sponge intertidal Glenelg, SA C, trachymt'sopwi sp. nov. mud to coarse sand with shells 21-293 Bass Strait Elaphognathia bifurcilla (Holdich sand 10-18.2 Bowling Green Bay. Qld and Harrison. 1980) /:. /<<™.v(Haswell. 1884) sand, silt clay and sessile intertidal-24 Port Jackson, NSW to Portland, invertebrates / plant holdfasts Vic. E. forceps (Holdich and Harrison, coral rubble on muddy shore intertidal Rowes Bay, Qld 1980) E. fivygatteUa sp. nov. coarse sand 35 km SSW of Cape Otway, Vic. E. riinifron.s (Holdich and Harrison, sandy mud 6.8-8.8 Halifax Bay, Qld 1980) Cibbagnathii europalolhorix sp. nov. medium to coarse sand 36-104 Bass Strait Gnalhia aspcrifron.s Holdich and rock scrapings intertidal Lizard I., Qld Harrison. 1980 O'. biorbis Holdich and Harrison, dead coral / barnacles intertidal Heron I. and Townsville. Qld 1980 G. calamilosa Monod, 1926 coarse sand to mud 29-204 Nowra, NSW to Eddystone Point. Tas. and west into central Bass Strait G. calmani Monod, 1 926 sand, bryozoans and dead coral intertidal- 1 13 Heron I., Qld and Portland Vic G. ccimponolu.s sp. nov. muddy to coarse sand and shell 55-135 Bass Strait and E of Port Jackson, NSW G. comma Holdich and Harrison, Teredo-bored wood intertidal Pallarenda, Qld 1980 C cpoposirumu sp. nov. medium sand 81 44 km SW off Cape Otway, Vic. G. talcipenis Holdich and Harrison, wood/coral intertidal- Magnetic 1. and Lizard I., 1980 Qld and North West Shelf, WA G. hak'i Cals. 1973 fine gravel to mud 136-188 Off Moreton I. and Capricorn Channel, Qld G. iridomyrmex sp. nov. red coralline algal turf 11 Portland, Vic. G. laiidens (Beddard. 1886) 12.8 Flinders Passage. Qld G. mclicolu Holdich and Harrison, wood / barnacles intertidal Townsville, Qld 1980 G. midicrana Hale. 1924 among Zo.stera sp. 12.8-14.6 Vic. to WA G- mystrium sp. nov. muddy sand to shelly sand 57-130 Bass Strait G. nolostixma sp. nov. coarse sand and gravel 75-200 S of Point Hicks, Vic. and oft' Broken Bay, NSW G. odontomacluts sp. nov. find sand and mud to sandy 8-13 Western Port, Vic. gravel (/'. prolasius sp. nov. coarse shelly sand 363-1000 Nowra, NSW to Freycinet Peninsula, Tas. I'HYLOCiENY AND MOGEOGRAPHY OF GNATHIIDAE 291 (i ihyliclopomra sp. no\ - 296-303 Western Coral Sea 0. stigmgcroi sp. nov medium sand to gravel 27-203 Eastern Bass Strait (i. Vdiit)httimliia Holdieh and coral inlertidal Heron 1.. QUI Harrison. 1980 Yldnottgnttthtu colobstrmna sp. nov. 1000 S of Point Hicks. Vic. \/ poiwra sp. nov. 1 550 Lord Howe Rise, Tasman Sea t'haitmaxtagnathia mctuplionc sp. shaded, sessile invertebrates 20 Pearson 1.. SA nov, '/'. Oni'togiultttus sp. nov. medium to very coarse sand 27-200 Bass Strait / nasinannici sp. nov. 122 20 km E of Falmouth, las. toria is also recorded from Heron I., Queensland Further evidence of local radiation is seen in but this is exceptional. This discovery of I'haumastognathia whose four species are con- extreme endemism on the southern coast is con- fined to the Australian or New Zealand shelf. sistent with the generalisations made by Wilson Although deep-water Australian species of the are and Allen ( 1 987). The extent to which the trop- genera Bathygnathia and Monodgnathia ical Australian species extend into the Indo- endemic they do not group into local complexes. West Pacific is unknown because ofthe low level The species seem to have arisen independently of sampling elsewhere. within widespread genera. Moreover, even within the small area studied, The species from the south-eastern slope have many species have limited distributional range. been recorded from few localities although two, The isopod collections of the Museum of Vic- (V. pm/asius, from 363 to 1000 m and C. leptan- toria are based on over 400 well-sorted samples illa, 22 to 800 m, cover a wide depth range. of benthos from Bass Strait and the south-east- Bathygnathia vollenhovia, reported from 800 ern Australian slope and of samples from sub- m, is the only species recorded from both sides of tidal rocky habitats. Only two species of more the Tasman Sea. The limited number of speci- than 30 could be said to be moderately well dis- mens of this species from the west coast of New tributed: Caecognathia leptanilla with records Zealand are not distinguishable from those from from 40 samples collected between 22 and 800 the Australian eastern slope. More specimens metres in Bass Strait and the eastern shelf and arc needed from both sides of the Tasman Sea to slope; and Caecognathia trachymesopus from 29 clarify the relationship between the Australian sites in Bass Strait between 21 and 293 metres. and New Zealand groups. All other species are recorded from fewer than Only one species, B. opsilhopsis, has been species with the recorded below 2000 m in Australia and gna- I 1 samples. The shallow-water greatest geographical range is G. midieraria thiids are noticeably absent from the limited recorded from Victoria to Western Australia. number of samples taken below this depth parts of the Because so little collecting has been done in (Poorect al., 1994) and rare in other Western Australia the likelihood remains that world. Only Bythognalhia yucatanensis Camp other species have this sort of distribution. from 3700-3800 m in the Caribbean, Caecogna- The south-eastern Australian gnathiid fauna thia caeca Richardson from 2638 m in the west- shows evidence of local radiation into endemic ern North Atlantic, and Bathygnathia segonzaci Atlan- species complexes (see cladogram). The Caecog- (Cals) from abyssal depths in the southern bathyal depths nathia agwillisi-compkx comprises C. pustulosa tic have been reported from (not included on this analysis but clearly related (Camp, 1988). to this complex), C. agwiBsi, and C. paratrechia and western Victoria and C. in South Australia Gnathiidae Leach huberia in Bass Strait and New South Wales. The cladogram suggests that the sister taxa of Gnathidcs Leach, 1X14: 432. this group arc species from Antarctic seas, C. Gnathiidae. — Hargec, 1880: 408. — Monod. C. trachymesopus-com- calva and C polaris. The 1926: 281-285 (synonymy) (and other authors) plex comprises C trachymesopus, C. leptanilla in Bass Diagnosis. Pereopods 1 modified as pylopods and C. diacamma from shelf habitats which lie under buccal cavity. Perconite 7 Strait and south-eastern Australia and C. bran- Pereopods 7 absent. chyponera from the slope in the same region. reduced, as wide as pleon. . 292 BRIAN F. COHEN AND GARY C. B. I'OORE Picon narrower than pcrcon. Sexually dimorp- sally. Female and praniza larva with pereonites hie. Male head fused to first pereonite; mandible 4-6 fused, inflated. Praniza ectoparasitic on in male large and projecting foward, visible dor- fish. Key to genera of Gnathiidae The key applies only to adult males and is written for ease of identification; it docs not reflect the phylogcnetic hypothesis. 1 Pylopod large, distinct; maxilliped 5-articled 2 — Pylopod very thin and elongate (difficult to see even under dissecting micro- scope), pereopod-like; maxilliped absent or greatly reduced 9 2. Pylopod of 5 or 6 articles; article 3 not reduced 3 — Pylopod of 2 or 3 articles; article 3 reduced or absent 7 3. Frontal border with processes, transverse; pronounced paraoccular ornamen- tation present Euneognathia — Frontal border without processes, rounded or produced; lacking paraoccular ornamentation 4 4. Pylopod pereopod-like, not operculate; pereonite 1 greatly produced Bythognathia — Pylopod operculate, not pediform; pereonite I not greatly produced ... 5 5. Pylopod 6-articled, article 2 reduced; mandibular blade dentate; animal small, < 5 mm Paragnathia — Pylopod 5-articled, article 2 greatly enlarged; mandibular blade smooth or absent; animal large, > 5 mm 6 6. Mandibles without blade; buccal cavity wall extension visible at the end of pronounced rostrum Bathygnathia — Mandibular blade smooth; frontal border rounded, without buccal cavity wall protrusion; percopod 4 basis with quadratic lobe Monodgnathia 7. Frontal border without frontal process, often rounded; cephalon lacking paraoccular ornamentation and dorsal sulcus Caeeognathia — Frontal border with frontal processes, often transverse; cephalon may possess paraoccular ornamentation and/or a dorsal sulcus 8 8. Frontal border not deeply excavated, mandibles not elongate Gnathia — Frontal border excavated; mandibles long, lacking a dentate blade Elaphognalhia 9. Pcrcon smooth, oval; pereonite 7 not visible; pleon often folded under pereon and antennae curved under mandibles; mandibles with crenulate blade and incisor Thaumastognathia — Pereon covered in granules and setae, rectangular; large dorsal, anteriorly- directed projection from pereonite 3; pereonite 7 visible, small; mandibles with highly reduced or absent blade, incisor absent Gibbagnathia Bathygnathia Dollfus -^ (type species: Akidognathia oedipus Stcbbing, Bathygnathia Dollfus, 1901:240. — Monod, 1926: 319. Type species. Anceus bathybius Beddard, 1886 Akidognathia Stebbing, L9I3; 12. — Monod, 1926: (original designation). PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 293 Diagnosis. Eyes absent or present. Frontal bor- groups. The first, including its type species, A. der produced as rostrum, often long; without oedipus, belongs in a clade with species of Bathy- processes; buccal cavity wall visible anterodor- gnaihia and is the sister taxon to the second sally. Mandibles straight, without blade. Pereon- clade. Akidognathia is therefore a junior syn- ite 1 reaching lateral margins of pereon. not onym of Bathygnaihia and a new genus, Mon- immersed in cephalon. Pylopod 5-articled; oper- odgnathia, is needed for the second clade. culate, second article enlarged; article 3 with 1 or A. segonzaci Cals is very tenatively placed in spiniform 2 setae; external margin lacking dense Bathygnaihia because of the shape of the man- cover of plumose setae. Pereopod 4 basis with- dible and the lack of a quadratic lobe on pereo- out anterior quadrate lobe, ischium distally pod 4 but the description of this species is very expanded or not; merus of pereopods laterally brief and only the ventral surface was figured. expanded in some species. There are 12 species identified in the litera- ture (Table 4) all confined to the deep sea at Remarks. Bathygnaihia is characterised by a 5- depths between 245 and 2698 m. The five newly articled. operculate pylopod, mandibles without described species of Bathygnaihia obvious blade and the protruding rostrum and are the first records of this genus from Australasian buccal cavity wall. Phylogenetic analysis separ- waters. ated the known species of Akidognathia into two Key to males of Bathygnathia from Australia and New Zealand 1 . Eyes present B. adlerzia — Eyes absent 2 2. Rostrum elongate, two-thirds length of cephalosome and narrow, one third width of cephalosome; pereopod 4 ischium not dilated distally B. vollenhovia — Rostrum rather broad, not elongate; pereopod 4 ischium dilated distallv 3 3. Pereonites 1-4 with ornate margins, raised distally; cephalon covered with numerous granules B. cardiocondyla — Cephalon and pereonites 1-4 relatively smooth 4 4. Mandibles indurate, with pronounced incisor: rostrum and cephalon without diamond-shaped translucent region B. opisthopsis — Mandibles thin and flexible in preserved material, without incisor; diamond- shaped translucent region on anterior cephalon B. tapinoma produced with ventrolateral walls Bathygnathia adlerzia sp. nov. of buccal cav- ity protruding. Holotype very heavily crystal- Figures 4-6 lised, no obvious remnants of setae visible on rostrum, Material examined. Holotype. North-western Coral rostrum badly torn. Eyes well devel- Sea (10°32.I'S, 144°12.1'E). 780-795 m, epibenthic oped, lateral, sessile and pale. External scissura sled. ORV Franklin. 20 August 1988 (AM stn 06/88 smoothly rounded. Cephalosome long, one- site 3), AM P4 1294(1 male). third length of animal; with broad dorsal sulcus Paratype. Type locality, AM P42273 (1 male). and low, posterior median tubercle. Antenna I Western Coral Sea Other material. (17°35'S, peduncle article 2 with a large plumose seta dis- 146°53'E). 458-500 m, epibenthic sled. M. Pichon et tally; flagellum of 5 articles, with 1 aesthetasc. al. on RV Cidaris. 15 Jun 1986 (stn 142.2), QM Antenna 2 peduncle twice as long as peduncle of W 19964 (1 male, anterior half only). antenna 1; flagellum incomplete, only three Description. Total length of holotype: 7.82 articles present. Mandible curved around ros- mm. trum, one-third length of cephalosome, cylindri- Cephalosome pentagonal, 1 .4 times as long as cal, lacking obvious blade, with unarmed carina; wide, lateral margins convex. Rostrum wide and seta one-third way along; slight mandibular inci- 294 BRIAN F. COHEN AND GARY C. B. POORE A2 Figure 4. Bathygnathia adlerzia. Holotype, AM P41294; A2 of paratype, AM P42180. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 295 Figure 5. Bathygnathia adlerzia. Holotype, AM P41294; P2 of paratype, AM P42180. 296 BRIAN F. COHEN AND GARY C. B. POORE Figure 6. Bathygnathia adlerzia. Holotype, AM P41294. sor near base of seta; 1 conical internal lobe thin median groove, twice as long as pereonites 2 ventrally opposite seta. Maxilliped 5-articled; and 3. Pereonite 6 with small lobuii. Pereonite 7 external margins of articles 2 to 4 bearing plu very narrow, overlapping pleon. Pleonites pro- mose setae; endite clearly reaching article 3 gressively longer and narrower, pleonal epimera wide, with 4 coupling hooks. Pylopod 5-articled prominent. Pleotelson subtriangular, longer article 1 elongate, firmly attached to article 2 than wide, with 7-8 pairs of simple setae lat- article 3 with 1 spiniform seta on external ante- erally. Uropodal peduncle without setae; rami rolateral margin and 7 simple setae medianly on subequal, reaching well beyond the apex of pleo- ventral surface; article 5 minute. telson; internal margins of rami bearing numer- Pereon widest anteriorly, slightly wider than ous plumose setae. cephalosome. Pereonite 1 large, laterally Pereopods with many posterior spiniform directed forward; dorsally reaching lateral mar- setae, particularly on carpus and with dense gins and laterally visible as one continuous cover of simple setae; bases of pereopods 2 and 3 band. Pereonites 2 and 3 subequal, as wide as narrower than bases of pereopods 4-6; pereopod pereonite 1. Pereonite 4 narrow, with anterior 4 ischium distally produced. constriction. Pereonite 5 with dorsal sulcus as Pleopods setose. Pleopod 2 endopod with PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 297 appendix masculina one-quarter length of rami. Pereon evenly sided, as wide as cephalosome Penes 2 contiguous papillae. except pereonite 5 which is wider around base of pereopods. Pereonite 1 dorsally raised forming Distribution. Western Coral Sea, 458-795 m depth. saddle-like structure with pereonite 2 laterally; dorsally small, not reaching lateral margins of Remarks. Bathygnathia adlerzia is only the sec- pereon and partially obscured laterally by per- ond species of Bathygnathia described with eonite 2. Pereonites 1-4 with granular ornate functional eyes and as such, it is easily separated borders. Pereonite 4 with raised ornate ridge from all others species except B. magnified near posterior border. Pereonites 2 and 3 much Moreira from Brazil. It differs from B. magnif- shorter than 4-6, pereonite 5 longest. Pereonite ied by having a shorter rostrum, mandibles with 6 lobuii thin and elongate. Pereonite 7 small, marked incisors and pereopod 5 lacking a distal very narrow, overlapping pleon. Pleonites pro- expansion of the ischium. gressively narrower, pleonal epimera promi- nent. Pleotelson subtriangular, tapering, as wide as long; lateral margins sinuous with 3 pairs of Bathygnathia cardiocondyla sp. nov. simple setae laterally. Uropodal peduncle with 2 Figures 7-9 setae; rami subequal. reaching beyond apex of pleotelson, internal margins bearing numerous Material examined. Hololype. Eastern Bass Strait. 47 plumose setae. km S of Cape Conran, Vic. (38°24.5'S, 148 42.1'E), Pereopods with dense cover of simple setae 1200 m. sand-silt-clay, pipe dredge, R.S. Wilson on particularly on basis; pereopod 2 with 1 pos- RV Tangaroa. 1 5 Nov 1981 (stn BSS 632) NMVJ8372 terior spiniform ( I male). seta on carpus; pereopod 4 with Paratvpe. Eastern Bass Strait. 121 km S of Cape numerous tubercles, carpus wide and ischium Conran. (38°55.6'S. 148°46.4'E). 1730 m. silty clay. with anterodistal projection. pipe dredge. R.S. Wilson on RV Tangaroa. 16 Nov Plcopods setose. Pleopod 2 endopod with 1981 (stn BSS 635) NMV J8371 (1 male). appendix masculina subequal to rami. Penes 2 Other material. New South Wales. East of Tcrrigal contiguous papillae. (33°26'S. 152°1 l'E), 868 m. sled-dredge. FV Kapata, 6 Dec 1979. (AM stn K79-20-12), AM P42099 (I Distribution. Southern NSW, eastern Bass male). Strait, 868-1730 m depth. Deseription. Total length of hololype: 6.85 mm. Remarks. Bathygnathia eardioeondyla is easily Cephalosome pentagonal, as long as wide, lat- identified and separated from all other Bathy- eral margins slightly convex. Eyes absent. gnathia. The raised and ornate appearance of Frontal border produced as broad rostrum; the edges of the cephalon and pereonites 1-4 is pointed, with 30 setae submarginally. Anterior unique amongst the Bathygnathia but similar in margin of rostrum raised; buccal cavity wall vis- some ways to Bythognathia yueatanensis ible anteriorly (particularly on paratype). Camp. Supraocular lobe smoothly convex. Cephalo- some covered with numerous granules: broad dorsal sulcus in distal half and small posterior Bathygnathia opisthopsis sp. nov. between dorsal sulcus and tubercle. Region Figures 10-12 frontal margin of rostrum translucent. Antenna Material examined. Holotvpe. New South Wales. E of 1 flagellum of 5 articles, with 2 aesthetascs. Newcastle, (33°03.6'S, 1 52"°48'E). 2632-2698 m, Men- Antenna 2 longer than antenna 1; flagellum of 6 zies trawl, W. Ponder and R.T. Springthorpe, 8 Oct articles (possibly some flagellum articles miss- 1982 (AM stn U216), AM P4218I (1 male). ing). Mandible half length of cephalosome, cyl- Paratype. Type locality, AM P42105 (I male). indrical with narrow apex; a slightly armed carina; pronounced proximal mandibular inci- Description. Total length of holotvpe: 7.67 sor; mandibular seta one-quarter way along; mm. conical internal lobe ventrally opposite incisor. Cephalosome pentagonal, as long as wide, lat- Maxilliped 5-articled; external margins of eral margins slightly convex. Eyes absent. articles 2 to 4 bearing plumose setae; endite Frontal border produced as broad rostrum; clearly reaching article 3, with 5 coupling hooks. pointed and raised, with few submarginal setae. Pylopod 5-articled: article 3 with 2 pectinate Buccal cavity wall clearly visible beyond setae on external anterolateral margin; articles anterior margin of rostrum. Supraocular lobe 2-4 with 13 setae medianly; article 5 minute. smoothly convex. Cephalosome smooth; with 298 BRIAN F. COHEN AND GARY C. B. POORE Figure 1. Bathygnathia cardiocondyla. Holotype, NMV J8372. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 299 Figure 8. Bathygnathia cardiocondyla. Holotype, NMV J8372. 300 BRIAN F. COHEN AND GARY C. B. POORE Figure 9. Bathygnathia cardiocondyla. Holotvpe, NMV J8372; Dorsal view of cephalon paratype, AM P42099. broad but shallow dorsal sulcus extending pos- lateral margin; articles 2-3 with few short setae teriorly to base of posterior median tubercle. on ventral surface; article 5 minute. Antenna 1 flagellum of 5 articles, with no aes- Pereon evenly sided, as wide as cephalosome thetasc. Antenna 2 twice as long as antenna 1; except pereonite 5 which is slightly wider around flagellum of 8 articles. Mandible half length of base of pereopods. Pereonite 1 narrow, clearly cephalosome, cylindrical with tapered apex; reaching lateral margins of pereon dorsally and armed carina extending to distal apex of man- visible laterally. Pereonites 2 and 3 much shorter dible; pronounced mandibular incisor and coni- than each of pereonites 4-6, pereonite 5 longest. cal internal lobe ventrally, opposite incisor. Pereonite 6 lobuii thin and elongate. Pereonite 7 Maxilliped 5-articled; external margins of small, overlapping narrow pleon. Pleonites pro- articles 2 to 4 bearing plumose setae; endite gressively narrower, pleonal epimera not promi- clearly reaching article 3. with 3 coupling hooks. nent. Pleotelson damaged; subtriangular, with Pylopod 5-articled: article 2 with 1 large aerola; rounded apex; wider than long; lateral margins article 3 with 2 strong setae on external antero- sinuous with up to 4 pairs of simple, short setae PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 301 Figure 10. Halhynnathia opisthopsis. Holotypc, AM P42I8I. 302 BRIAN F. COHEN AND GARY C. B. POORE Figure 11. Balhygnalhia opisthopsis. Holotype, AM P42181; P5 and P6 of paratype, AM P42105 PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 303 Figure 12. Bathygnathia opisthopsis. Holotype, AM P42181. laterally. Uropodal peduncle without setae; rami Bathygnathia tapinoma sp. nov. subequal, long and narrow, reaching well beyond apex of pleotelson, external margins Figures 13-15 bearing numerous setae. Material examined. Holotype. New Zealand. Off W Pereopods with dense cover of simple setae coast of South Island (42°15.9'S, 170"1.8'E), 924 m, particularly distally; pereopods 2 and 3 less stout letter-box dredge, P.K. Probert, 17 Feb 1982 (NZOI than pereopods 4-6; ischium of pereopod 4 with stn Q689A), NZOI H-618 (1 male). very pronounced anterodistal projection, dis- Paratype. Type locality, NMV J4753 (2 males). Other material. Type locality, NMV J4755 (1 tally flattened with numerous small tubercles. female). Pleopods setose. Pleopod 2 endopod with appendix masculina three-quarters or almost as Description. Total length of holotype: 5.39 long as rami. Penes 2 contiguous papillae. mm. Cephalosome pentagonal, 1 .4 times as long as Distribution. Southern NSW, 2632-2698 m. wide, lateral margins convex. Entire frontal bor- Remarks. Bathygnathia opisthopsis possesses der produced as very wide rostrum with many similar body proportions and similar mandibles setae on anterior margin; ventrolateral walls of to those of B. cardiocondyla but lacks the raised buccal cavity protruding considerably beyond and ornate margins of the anterior pereonites. rostrum. Cephalosome with large, diamond- Both species are characterised by the weakly shaped translucent region on rostrum. Eyes armed mandibular carina. B. opisthopsis was absent. External scissura smoothly rounded. collected almost 1000 m deeper than any other Antenna 1 flagellum of 5 articles, with 3 aesthe- specimen of Bathygnathia. tascs; antenna 2 longer than antenna 1 ; flagellum M)4 I BRIAN . COHEN AND GARY C. B. POORE Figure 13. Bathygnathia tapinoma. Holotype, n/oi H-618. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 305 Holotype, NZOI H-618. Figure 14. Bathygnathia iapmoma. 306 BRIAN F. COHEN AND GARY C. B. POORE Figure 15. Bathygnatkia tapinoma. Holotypc, NZOl H-618. of 8 articles. Mandible soft and flexible in pre- partially obscured laterally by pereonite 2. Per- served specimens; one-third length of cephalo- eonite 3 narrowest, pereonites 4-6 progressively some; distally raised in lateral view; apex curved wider. Pereonite 4 with anterior constriction inwards; cylindrical, with no recognisable blade; and thin median groove. Pereonite 5 with dorsal a unarmed carina; seta one-third way along; sulcus as thin median groove. Pereonite 6 with inferior conical internal lobe distal to seta. very small lobuii. Pereonite 7 very narrow, over- Maxillipcd 5-articlcd; external margins of lapping pleon. Pleonites progressively longer articles 2 to 4 bearing plumose setae; endite and narrower, pleonal epimera not prominent. clearly reaching article 3, with 4 coupling hooks. Pleotelson subtriangular, longer than wide; lat- Pylopod 5-articled; internal margin with few eral margins straight; with 7-8 pairs of simple well-spaced long plumose setae proximally and setae laterally and pair of seta on distal apex. short plumose setae distally; anteromedianly Uropodal peduncle with 1 seta; endopod longer with numerous simple setae; article 1 elongate, than exopod, reaching beyond apex of pleotel- firmly attached to article 2; articles 1 and 2 with son; internal margins of rami bearing numerous areolae; article 3 with 2 pectinate setae on exter- plumose setae. nal anterolateral margin; fifth article minute. Pereopods with many posterior setae and Pereon widest at pereonite 2, slightly wider dense cover of simple setae; pereopods 2 and 3 than cephalosome; pereonites progressively less robust than 4 to 6; pereopod 4 basis without longer. Pereonite 1 dorsally reaching lateral quadrate lobe, ischium distally expanded as con- margins, divided into 3 regions by ccphalon and cave circular cusp with 10 or more tubercles. PHYLQGENY AND BIOQEOGRAPHY OFGNATHHDAE 307 Pleopods setose. Pleopod 2 endopod with .^-articled, with many setae medianly on ventral appendix maseulina three-quarters length of surface; margin ol article 2 with several plumose rami. Penes 2 Contiguous papillae. setae; article 3 with 1 pectinate seta on external anterolateral margin; fifth article minute. Distribution. Wcsl coast ofSouth Islam! of New Pereon evenly sided, as wide as cephalosome. Zealand, l)24 m. Pereonite I large, laterally directed forward; Remarks. Bathygfiathfa tapinoma is most simi- reaching lateral margins dorsally anil visible as lar to H. oedipus (Stebbing) and both are charac- continuous band laterally. Pereonite 2 and 3 terised by the presence of a pronounced distal suhcqual. shorter than pereoniles4 -6, I'ereonile extension on the ischium of pereopod 4; weak 5 with dorsal sulcus as thin median groove. Per mandibles located closer to the lateral margin on eonite 7 very narrow, overlapping pleon. Pleon- the frontal border than in most other species; ile I wider than other pleonites, pleonal epimera and similar pereon and pleotelson dimensions. prominent, Plcotelson subtriangular, as wide as H, tapinoma differs from />. oedipus in pos- long, lateral margins sinuous with 17-18 pairs oi' sessing a wider yet shorter rostrum and a large simple setae laterally and 3 setae medianly. I fro- diamond-shaped translueent region at the base podal peduncle with 4 setae; endopod longer of the rostrum. than exopod, reaching beyond apex of pleotel- son; rami bearing numerous plumose setae dis- Bathynnathia vollenhoviu sp. no v. tally. Pereopods with dense cover of simple setae figures 16-18 and with many strong posterior setae, particu- Material examined. Holotypc. Tasmania, ofFFreyct- larly on carpUS! pereopods 4-6 more stout than 2 nel Peninsula (42°2.20'S, 148'38.70'E), 800 m, coarse and 3, with laterally enlarged merus. shelly sand, whoi epibenthic sled, Ml ( romon el al. Pleopods setose. Pleopod 2 endopod with onORV Franklin, 27 Jul 1986(stnSl OPE 45), nmv appendix maseulina half length of rami. Penes 2 J i 9 1 20 (I male). contiguous papillae. Other material. New Zealand, oifw coast of South l Island. (42'l.\')'S, I7()"I.8'H), >24m, letter-box Distribution. Tasman Sea, oil' west coast of dredge, P.K. Probert, 1 7 Feb 1 982 (ephalosome pentagonal. 1 .4 times as long as dard) and />'. monodi Cais, All possess a long wide, lateral margins Rostrum narrow convex. narrow rostrum of similar proportions. These greatly half length of eephalon; at and produced; three species, and H cmnrostris Richardson, />' base approximately one-third width of cephalo- affinis Uirslcin and />' BOTCH Kensley, form a short setae on anterior margin. some: with many complex of species characterised by a most pro- Ventrolateral walls Of buccal eavity protruding nounced rostrum and expand merus of some or anteriorly; eephalon with translueent elliptical all of pereopods 2 (>. a. vollcnhovia differs from region rostrum (faded in some material). on B, hitthyhiiis in possessing a more complex man- smoothly Eyes absent. External seissura dible characterised by incisors and an opposing low, acute. rounded. Supraocular lobe very straight distal region; and from H numoi/i in a dorsal sulcus, ( ephalosome with broad, shallow more complex and rounded mandible, shorter low, very small two-thirds length of eephalon; translucent elliptical region confined entirely to Antenna llagellum of posterior median tubercle. the rostrum and eephalon with a posterior 4 aeslhetascs; antenna 1 of 5 articles, with tubercle and dorsal sulcus. antenna 2 longer than antenna I; llagellum of 6 articles. Mandible subequal to length of ccpha- Bythognathia ( amp losome (excluding rostrum); proximal two- thirds slightly curved, distal third with internal Bythagnathia Camp, 1988: 668. forming vice-like structure; margins parallel, Type species, livtho^nathia vitcataiicivos ( 'amp, carina; slight mandibular incisor with unarmed i°88 (original designation). almost half-way along; lacking seta. Maxilliped 5-artieled; external margins of articles 2 to 4 Diagnosis, byes absent, frontal border pro- bearing plumose setae; endite clearly reaching duced into rostrum, without processes. Mandi- article 3, wide, with 5 coupling hooks. Pylopod bles Straight, lacking obvious blade. Pereonite I 308 BRIAN F. COHEN AND GARY C. B. POORE Figure 16. Bathygnathia vollenhovia. Holotype, NMV J 19 120. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 309 J 19120. Figure 17. Bathygnathia vollenhovia. Holotype, NMV 310 BRIAN F. COHEN AND GARY C. B. POORE Figure 18. Bathygnathia vollenhovia. Holotype, NMV J 19120; Dorsal view of cephalon of NMV J4754. produced, partially obscuring pereonite 2; The phylogenetic analysis supports the retention clearly reaching lateral margins of pereon. Pylo- of the generic name. The genus does not occur in pod 6-articled (sixth article fused), not opercu- Australia. late, subchelate and pediform. Caecognathia Dollfus Remarks. Bythognathia is a monotypic genus from very deep water in the Caribbean Sea Caecognathia Dollfus, 1901: 240. — Tattersall, It is characterised the very (Camp, 1988). by 1906: 61. pereonite 1. is large and produced Bythognathia Gnathia (Perignathia) Monod, 1922: 645 (type the only gnathiid with a 6-articled, non-opercu- species: Anceus abyssorum Sars, 1872 or Gnathia fal- late pylopod which is pediform and subchelate. lax Monod, 1926. See Remarks under Gnathia). . 3 I PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 1 Heterognathia Amar and Roman, 1974: 569 (type (Wagele, 1987) herein transferred to Caecogna- species: Heterognathia adeliensis Amar and Roman, thia. This genus is therefore a junior synonym of 1 974). Caecognathia. The nomenclatural status of Per- ot* Gnathia (Perignathia). — Monod. 1926: 554- as igm thia is uncertain but of little consequence 55 -v long as it remains a junior synonym; see Tvpe species. Anceus stvgius Sars, 1877 (original Remarks under Gnathia. designation). Gnathia and Caecognathia are closely related synonymised. They share many ^ , r genera formerly Diagnosis. Eyes present. Frontal margin of similaritieSi particularly the structure of the cephalon produced, without frontal processes. pylopod but Caecognathia is distinguished by a Mandibles usually with smooth mandibular frontal pro- produced fronta i border lacking any blade. Cephalon without paraocular ornamen- cesses The genus includes most species of tation or dorsal sulcus. Pereonite 1 immersed in - Monod s (i 926) Sectio Productae of Gnathia. cephalon. Pylopod 2- or 3-articled, operculate, j i described Australian The on , y prev ous y enlarged, article small or absent. article 1 3 species assigned to this genus are C. agwillisi Victoria (Fig. Remarks. The type species of Heterognathia, H. (Seed, 1979) from rocky shores in pustulosa (Hale, 1 924) from sponges adelaidensis, is a juvenile male of the common 2 A) and C. Table 5). Antarctic species, Gnathia calva Vanhoffen in South Australia (Fig. 2B and Key to males of Australian species of Caecognathia C. agwillisi 1. Pleotelson trapeziform, apex broadly truncated - — Pleotelson subtriangular increasing posteriorly to per- 2. Cephalosome elliptical; pereon width evenly (see figs 19, 22, 34, 40) eonite 5; pereonite 6 with marked globular lobuii — Cephalosome roughly quadrilateral; pereon width not steadily increasing simple, rounded lobui 1 posteriorly; pereonite 6 without lobuii or at most with only C ^'Planilla 3. Rostrum produced — Rostrum not produced margin Pereonite 6 with pronounced suture midway along lateral 4 C diacamma — Pereonite 6 without suture lateral margins of body; frontal border smoothly 5 Pereonite 1 barely reaching hrachyponera rounded with rounded external scissura C lateral margins of body, divided into 3 regions by — Pereonite 1 clearly reaching with a slight median indentation nosterior margin of cephalon; frontal border C trachymesopus and very shallow external scissura pylopod 2- 2 mesiolateral and I medially; 6. Cephalon with 3 furrows, articled — Cephalon without furrows; pylopod 3-articled 9 quadrate lobe; pereonite 4 with posterior bUobed 7. Mandibles with internal projection with anterior spine 8 _ Mandibles lacking internal lobe; pereonite 4 without mandibular setae, blade a smooth arc; 8 Body not setose; mandibles pronounced .... tubercle, spine on peronite 4 . i,cpiicephalon without low 1. C. pustulosa .. 312 BRIAN F. COHEN AND GARY C. B. POORE — Body setose, especially anteriorly; mandibles with mandibular setae, blade slightly asssymetrical. produced; posterior cephalon with small tubercle . C. huberia 9. Mandibles with armed carina; small opaque spines on cephalon, visible in lateral view; frontal border produced as a rostrum; pereopod 4 basis not pro- duced distally , . . C. dolichoderus — Mandibles cylindrical, without armed carina; no spines on cephalon; frontal border not produced as a rostrum; pereopod 4 basis expanded distally . . C. gnamptogerys Caecognathia branchyponera sp. nov. obscured laterally by pereonite 2. Pereonites 5 and 6 each twice as long as pereonites 2-4; pos- Figures 19-21 terior border of pereonite 6 markedly concave Material examined. Holotvpe. New South Wales, 44 with distinct gobular lobuii. Pereonite 7 very km E or Nowra (34°55.79'S. 151°08.06'E), 429 m, narrow, overlapping pleon. Pleon with pleonites muddy coarse shell, WHOI epibenthic sled, G.C.B. subequal, epimera prominent. Pleotelson sub- Poore et al. on RV Franklin, 22 Oct 1988 (stn SLOPE triangular, longer than wide; lateral margins 56). NMV .127575 (1 male). slightly sinuous; with 3 pairs of plumose setae Paratypes. Tvpe locality, NMV J 19 1 26 (6 males). laterally and pair of setae on distal apex. Uropo- Other material. Tvpe locality, NMV J29889 (4 females). Vic. S of Point Hicks (38°I7.70'S, dal peduncle with 1 plumose seta on internodis- 49° 1 1 1.30'E). 400 m, coarse sand, gravel, mud, many tal margin; rami subequal, not reaching apex of sponges. WHOI epibenthic sled, M.F. Gomon ct al. on pleotelson; internal margins of rami bearing RV Franklin. 24 Jul 1986 (stn SLOPE 40), NMV numerous plumose setae. .119125 (80 specimens). Pereopods with moderate cover of plumose Description. Total length: 3.09 mm. setae, particularly on basis and few, pronounced Cephalosome elliptical. 1.2 times as long as lateral projections on anterior face of ischium to wide, lateral margins convex. Eyes well devel- carpus. oped, lateral and sessile. Frontal border slightly Pleopods setose. Pleopod 2 endopod lacking produced, rounded; with 5 submarginal setae appendix masculina. Penes 2 small contiguous each side of mid-dorsal line. External scissura papillae. smoothly rounded. Supraocular lobe smoothly Distribution. Eastern Bass Strait, eastern NSW, convex. Antennae stout, subequal; flagellum of 400-429 m. antenna 1 of 5 articles, without aesthetascs; fla- gellum of antenna 2 of 3 articles. Mandible Remarks. Caecognathia branchyponera belongs strongly curved, one-third length of cephalo- to a complex of species characterised by a some; with unarmed carina; smooth double- roughly elliptical cephalosome; simple mandi- scalloped blade on distal two-thirds, distal bles; pear-shaped pereon; presence of globular scallop twice as long as proximal scallop; basal lobuii; and distinct pylopods (article 2 is not cir- neck ventrally smoothly arced, dorsally covered cular). The three species C. leptanilla, C. trachy- by pronounced erisma. Erisma with dense mesopus and C. diacamma also belong to this covering of fine setae on external margin. Maxil- complex. liped 5-articled; palp thin and elongate; external C. branchyponera most closely resembles C. margins of articles 2-4 bearing plumose setae; trachymesopus though is distinguishable by the endite clearly reaching article 3. wide. Pylopod smaller pereonite 1 which is not divided into 3-articled: internal margin of plumose setae; three regions; a flatter frontal border with evenly spread article 1 with 4 plumose setae on ventral surface; small setae, a deeper external scissura article 2 conical, proximal margin completely and no median indentation. joined to article i. with 3 setae on ventral sur- face: article 3 minute. Caecognathia diacamma sp. nov. Percon width increasing posteriorly; widest at pereonite 5, 1 .75 times as wide as cephalosome: Figures 22-24 margins with numerous setae. Pereonite 1 barely Material examined. Holotvpe. Victoria, western Bass reaching lateral margins dorsally and partially Strait. 26 km SW of Cape Otway (39°01.0'S, PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 313 Figure 19. Caecognathia branchyponera. Holotype, NMV J27575. 314 BRIAN F. COHEN AND GARY C. B. POORE P3 P2 >*>*^ %j hJi J" X P5 Figure 20. Caecognathia branchyponera. Holotype. NMV J27575. 1 l'HYLOGENY AND BIOGEOGRAPHY OF GNATHUDAE 315 .127575. Figure 21. Caecognathta branehyponem. Holotypc, NMV colour. Cephalosome elliptical; posterior 143°22.1'E). 84 m. medium sand, WHOI epibenthic Pale 3 Jan 1 98 only slightly curved, broad; cephalo- sled, M.F. Gomon ct al. on RV llai Kung, 1 margin lateral margins (stn BSS 120). NMV J27569 (1 male). some 1.3 times as long as wide, Paratypcs. Tasmania, western Bass Strait, 59 km convex. Eyes well developed, lateral and sessile. (39°28'S. 143°17'E), WNWofCape Farewell, King 1. Frontal border slightly produced, rounded with Smith-Mclntyre grab, G.C.B. 103 m, coarse sand, slight median projection; lOsubmaginal setae of Kimbla. 10 Oct 1980 (stn BSS 81), Poore on HMAS differing sizes on each side of median projec- NMV J8316 (3 males). absent. Supraocular lobe Western tion. External scissura Victoria. Various collectors, 1980-1981. antenna 1 (38°38.2'S. smoothly convex. Antennae subequal; Bass Strait, 30 km SSW of Warrnambool BSS down-turned in lateral view, flagellum of 5 142°35.0'E), 59 m, WHOI epibenthic sled (stn of Cape long, only marginally shorter than ped- 188)" NMV J8321 (2 males). 51 km SSW articles, sand, flagellum of antenna Otway (39°16'S, 143°17'E), 90 m, medium uncle, without aesthetascs; Smith-Mclntyre grab (stn BSS 73), NMV J8320 <1 2 of 6 articles. Mandible strongly curved, one- (39°06'S, 14321 E), male). 35 km SSW of Cape Otway third length of cephalosome; with unarmed car- grab (stn BSS 57), 59 m coarse sand, Smith-Mclntyre ina; smooth blade on distal two-thirds; basal SW of Cape Otway NMV .18317 (2 males). 26 km neck smoothly arced; erisma pronounced. 84 m, medium sand, WHOI (39°01 0'S 143°22.1'E), Maxilliped 5-articled, palp thin and elongate; NMV J8313 (7 males). epibenthic sled (stn BSS 120), 2-4 bearing plumose 143'28 E 92 m external margins of articles 25 km S of Cape Otway (39°06.7'S, 7 , reaching article 3, wide. (stn BSS 119).NMV setae; endite clearly fine sand, WHOI epibenthic sled Otway (38 58 S Pylopod 3-articled, with dense internal margin J83P(4malcs). 11 km SSW of Cape Smith-Mclntyre grab setae; article 1 with 75-80 plumose 143°-| 9'E) 67 m, medium sand, of plumose 1 km S of Cape article 2 conical, pos- ( 1 male). 5 ventral surface; (stn BSS 5 1), NMV J8319 setae on sand medium 1 with Otwav (39WS. 143°32'E). 79 m, terior margin completely joined to article , male). 25 km So Cape (stn BSS 50, NMV J8318. (1 7 simple setae on ventral surface; article 3 min- 43'35.8'E), 95 m, fine sand WHOI Otway (39'06.0'S, 1 ute. NMV .18315 (4 males), epibenthic sled (stn BSS 118), Pereon width increasing posteriorly; widest at (2 males). NMV J8314 peronitc 5, 1.5 times as wide as cephalosome, short setae. Per- holotype: 5.29 margins with numerous fine, Description. Total length of eonite 1 dorsally reaching lateral margins and mm. 316 BRIAN F. COHEN AND GARY C. B. POORE Figure 22. Caecognathia diacamma. Holotypc, NMV .127569. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 317 Figure 23. Caecognathia diacamma. Holotype, NMV J27569. 318 BRIAN F. COHEN AND GARY C. B. POORE Figure 24. Caecognathia diacamma. Holotype, NMV J27569. partially obscured laterally by pereonite 2. Per- Caecognathia dolichodems sp. nov. eonite 6 with pronounced globular lobuii and Figures suture midway on lateral margins. Pereonite 7 25-27 very narrow, overlapping pleon. Pleon broad Material examined. Holotype. Tasmania, eastern Bass with irregular lateral Strait, borders; pleonites 1 and 5 63 km E of North Point. Flinders I. (39°44.8'S, narrower than others; epimera prominent. Pleo- 148°40.6'E), 124 m, muddy sand, Smith-Mclntyre telson subtriangular, as wide as long, with grab, R.S. Wilson on RV Tangaroa, 14 Nov 1981 (stn BSS numerous tubercules and 12-17 pairs of plu- 167), NMV J27561 (1 male). Paratypes. Most mose setae laterally and 2 medianly. Uropod collected using WHOl epibenthic sled by R.S. Wilson on RV Tangaroa. Nov 1981. peduncle without setae; rami subequal, not Tas. Eastern Bass Strait, 100 km NE of North Point, Flin- reaching apex of pleotelson; exopod bearing ders I. (38°52.6'S, I48°25.2'E), 130 m, fine sand (stn numerous plumose setae. BSS 1 70), NMV J8333 (3 males). 85 km NE of North Pereopods with dense cover of plumose setae; Point, Flinders I. (39°02.4'S, 148°30.6'E), 120 m, with few lateral projections on anterior faces of muddy sand (stn BSS 169), NMV J8335 (4 males). to carpus; 60 ischium pereopod 4 smaller than km E of North Point, Flinders I. (39°41.7'S, others. 148°39.5'E), 115 m, muddy sand, naturalists' dredge, G.C.B. Pleopods setose. Pleopod 2 endopod lacking Poore on HMAS Kimbla, 27 Mar 1979 (stn BSS appendix masculina. Penes 2 small contiguous 32), NMV J8336 (2). 63 km E of North Point Flinders papillae. I. (39°44.8'S, I48°40.6'E), 124 m, muddy sand, Smith-Mclntyre grab (stn BSS 1 67), NMVJ8334 Distribution. Western Bass Strait, 59-103 m. (1 male). Remarks. Caecognathia diacamma is character- Description. Total length of holotype: 3.15 ised by the distinct suture on the lateral margins mm. of pereonite 6. Cephalosome rectangular with pronounced PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 319 J27561 Figure 25. Caecognathia dolkhodems. Holotype, NMV 320 BRIAN F. COHEN AND GARY C. B. POORE Figure 26. Caecogwtkia dotichodems. Holotype, NMV .12756 1. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 321 Figure 27. Caecognathia doliehoderus. Holotypc. NMV J27561. rostrum, 1.15 times as wide as long, lateral mar- gressively longer and wider, epimera prominent. gins convex and irregular. Eyes well developed, Pleotelson subtriangular, longer than wide; lat- lateral and sessile. Frontal border produced as eral margins straight; with 2 pairs of simple setae rostrum, smoothly rounded with 1 4 setae spread and pair of setae on distal apex. Uropodal ped- submarginally. External scissura rounded. uncle with 1 seta; endopod longer than exopod, Supraocular lobe not pronounced. Cephalosome reaching apex of pleotelson margins; rami bear- with many small spines anteriorly, visible in lat- ing long simple setae. eral view. Antennae stout, subequal; flagellum of Pereopods with moderate cover of large plu- antenna 1 of 5 articles, with 3 aesthetascs; fla- mose setae, particularly on basis and ischium; gellum of antenna 2 of 6 articles. Mandible one- elsewhere few, short simple setae. Pereopods 2 third length of cephalosome with sparse cover- and 3 with few acute projections on lateral faces ing of small fine setae; armed carina; pro- of merus-carpus. nounced mandibular incisor; mandible tightly Pleopods setose. Pleopod 2 endopod lacking closing around rostrum. Maxilliped 5-articled; appendix masculina. Penes 2 small contiguous external margins of articles 2-4 bearing plumose papillae. setae; endite clearly reaching article 3, wide, Distribution. Eastern Bass Strait, 115-130 m. with 1 coupling hook. Pylopod 3-articled, internal margin lacking long setae; article 1 with Remarks. Caecognathia doliehoderus does not 2 setae on ventral surface distally and 5 plumose closely resemble any previously described setae at basis; article 2 with 1 seta on ventral species. It is characterised by flat mandibles with surface; article 3 minute. a large incisor and very well armed carina, which Percon dorsoventrally flattened; widest anter- fit snugly around the rostrum. iorly, as wide as cephalosome; covered with Caecognathia gnamptogenys sp. nov. numerous long simple setae. Pereonite 1 dor- Figures 28-30 sally fused with cephalosome and not visible laterally. Pereonites 2 and 3 subequal, pereon- Material examined. Holotype. Victoria, S of Point ites 4-6 narrower and longer than 2 and 3; per- Hicks (38°21.90'S, 149°20.00'E). 1000 m, WHOI cpi- eonite 6 with small, rounded lobuii. Pereonite 7 benthic sled, G.C.B. Poore et al. on RV Franklin. 23 very narrow, overlapping pleon. Pleonites pro- Jul 1986 (stn SLOPE 32), NMV .119116(1 male). 322 BRIAN F. COHEN AND GARY C. B. POORE i igure 28, Caecognatkta gnamptogenys. Holotype, nmv .119116. PHYLOGENY AND BIOGEOGRAPHY OF GNATH11DAE 323 Figure 29. Caecognathia gnamptogenys. Holotype, NMV J 191 16. 324 BRIAN F. COHEN AND GARY C, B. POORE Figure 30. Caecognathia gnamptogenys. Holotype, NMV J 191 16. Description. Total length of holotype: 7.4 mm. surface medianly; article 2 with 7 setae on ven- Cephalosome quasipentagonal, lateral mar- tral surface distally; article 3 minute. gins posterior to eyes rounded, frontal margin Pereon widest anteriorly, wider than cephalo- rounded. Eyes ventrolateral. Frontal border pro- some, covered with numerous simple setae. Per- duced, conical, with 1 2 setae submarginally each eonite 1 dorsally fused with cephalosome, vis- side in 2 rows of 6: 1 row on rounded ventral ible as 2 small regions laterally on cephalosome. buccal wall extension; other row on frontal bor- Pereonite 3 with ventrolateral extensions, per- der. Lamina dentata visible. External scissura eonites 5 and 6 together as long as 2 to 4 together. very shallow. Supraocular lobe very low, acute. Pereonite 7 very narrow, overlapping pleon. Cephalosome with low, posterior median Pleonites subequal, pleonal epimera prominent. tubercle with 6-7 long setae. Antenna 2 longer Pleotelson elongate, 1.5 times as long as wide, than antenna 1; flagellum of 1 antenna of 5 with 2 pairs of simple setae. Uropodal peduncle articles, with 3 aesthetascs; flagellum of antenna with 1 seta; rami subequal, reaching apex of 2 of 7 articles (right antenna 1 flagellum of only 3 pleotelson; internal margins of rami bearing articles and 1 aesthetasc, terminal article as long numerous plumose setae. as 3 and 4 articles of left flagellum). Mandible Pereopods with dense cover of simple setae. straight, raised in lateral view, one-third length Pereopod 3 smaller than others; basis of pereo- of cephalosome; cylindrical, lacking obvious pod 4 with distal conical projection. blade; with unarmed carina. Maxilliped 5- Pleopods setose. Pleopod 2 endopod with articled; external margins of articles 2-4 bearing appendix masculina half length of rami. Penes 2 plumose setae; endite barely reaching article 3. small contiguous papillae. Pylopod 3-articled, with internal margin of plu- Distribution. Eastern slope of mose setae; article 1 with 3 areolae, second Bass Strait, 1000 m. areola very elongate, with 27 setae on ventral PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 325 Remarks. Caecognathia gnamptogenys is with long irregular basal neck proximally giving characterised the by distal expansion of the basis blade produced and irregular appearance. of pereopod 4; eyes situated more ventrolater- Maxilliped 5-articled; external margins of ally than in other species; and short and simple articles 2-4 bearing plumose setae; endite barely mandibles. C. serrata (Richardson) from the reaching article 3, with 2 coupling hooks. Pylo- Atlantic Ocean shares similar features but pos- pod 2-articled. article 2 small; internal margin of sesses a greatly produced frontal border. fine short setae; article 1 operculate, with 4 setae distally on ventral surface; article 2 with 6 setae on ventral surface, Caecognathia huberia sp. nov. Pereon evenly sided, as wide as cephalosome. Pereonite 1 barely reaching lateral margins Figures 31-33 dor- sally and partially obscured laterally by pereon- Material examined. Holotype. Victoria, western Bass ite 2. Pereonites progressively longer. Pereonite Strait. 50 km SSW of Warrnambool (38°49.5'S. 4 with slight anterior constriction; small, anter- 142°35.4'E). 89 m. coarse sand, R.S. Wilson on RV iorly directed median spine and smoothly Tangaroa. 21 Nov 1981 (stn BSS 190). NMV J27565 rounded median extension of posterior margin. ( 1 male). Pereonite 5 with dorsal sulcus and areae lat- Paratypes. Tasmania, western Bass Strait, 59 km W erales. Pereonite 6 with lobi laterales and of Stokes Point. King I. (40°07'S. 143°14'E). 185 m. sandy mud, Smith-Mclntyre grab. G.C.B. Poore on rounded lobuii. Pereonite 7 very narrow, over- HMAS Kimbla, 11 Oct 1980 (stn BSS 104), NMV lapping pleon. Pleon progressively narrower, .18364(1 male). with numerous large setae: pleonal epimera Victoria, western Bass Strait. 50 km SSW of Warr- prominent. Pleotelson subtriangular, wider than nambool (38°49.5'S, 142°35.4'E). 89 m. coarse sand. long, with pair of simple setae medianly and pair R.S. Wilson on RV Tangaroa. 21 Nov 1981 (stn BSS of setae on distal apex. Uropodal peduncle with 1 90). NMV J8363 (3 males). 5 km S of Point Reginald 1 seta; endopod longer than exopod. reaching (38°48.0'S, 1 43"14.5'E), 47 m, hard rocky bottom. R.S. beyond the apex of pleotelson; rami margins Wilson on RV Tangaroa, 20 Nov 1981 "(stn BSS 185). with a few long simple setae. NMV J8362 (2 males). Eastern Bass Strait. 1 1 .7 km W of Pt Ricardo (37°49.89'S. I48°30.13'E). 27 m. coarse Pereopods subequal. with few simple setae; sand. Smith-Mclntvre grab, N. Coleman on RV Sarda few lateral projections, mainly on carpus and (stn MSL-EG 105), NMV J24635 (3 males): (stn MSL- merus: tubercles on basis of pereopod 3 and EG 78) NMV J24634 (1 male). 7.3 km SSW of Cape basis-merus of pereopod 6. Conran (37°52.65'S, 148°42.15'E). 49 m. coarse sand, Pleopods without setae. Pleopod 2 endopod Smith-Mclntyre grab, N. Coleman on RV Sarda. Feb lacking appendix masculina. Penes 2 small con- 1991 (stn MSL-EG 116). NMV J24636 (1 male). tiguous papillae. Description. Total length of holotype: 2.99 Distribution. Bass Strait. 27-185 m. mm. Remarks. Caecognathia huberia belongs to a Eyes well developed, lateral and sessile. complex of south-eastern Australian species Frontal border produced medianly. truncated, most easily recognised by the mesial and oblique with 2 slight lateral depressions near internal posterior grooves on the cephalon. The other margin of mandible: 6 short setae medianly and species in this complex are C. pustulosa (Hale), 4 longer setae laterally. External scissura deep, C. agwillisi (Seed) and C. paratrechia. C. huberia smoothly rounded. Supraocular lobe not pro- is very similar to C. pustulosa (Hale) but differs nounced. Cephalosome and pereon with numer- by being hirsute, particularly anteriorly: pos- ous granules and long simple setae: with sessing a smaller anterior spine on pereonite 4: anterior, furrow and shallower, oblique mesial possessing a distinct posterior extension on posterior mesolateral furrows and low. posterior peronite 4; smoothly rounded external scissura; stout, down-turned; median tubercle. Antennae and mandibles with a more complex blade and antenna 1 longer than antenna 2, flagellum of 4 pronounced incisors. articles, with 3 aesthetascs; flagellum of antenna than article 4 of peduncle. 2 of 4 articles, shorter Caecognathia leptanilla sp. nov. Mandible curved inward, one-third length of cephalosome, slightly asymmetrical; with Figures 34-36 unarmed carina; pronounced mandibular inci- Material examined. Holotype. Tasmania, central Bass short sor one-third to halfway along: setae near Strait, 25 km SW of Cape Frankland, Flinders I.. incisor; smooth arc-shaped blade on distal half (40°09.4'S, 147°32. 6'E). 51 m. shelly sand. WHOI epi- 326 ('. BRIAN I . ( OllhN AND (,AKY li. I'OORh Figure 31. Caecognathia huberia. Holotype, NMV .127565. IMIYI (K;i:nY AND M(X;i;()(;RAPHY ()l (iNA'IIIIIDAi: 327 Figure 32. Caecognathia huberia. Holotype, NMV .127565. 328 BRIAN F. COHEN AND GARY C. B. POORE Figure 33. Caecognaihia huberia. Holotype, NMV J27565. benthic sled, R.S. Wilson on RV Tangaroa, 14 Nov Cape Paterson (38°56.4'S, 145M6.6'E), 70 m, line sand 1981 (sin BSS 162), NMV .127562 (I male). (sin BSS 155), NMVJ8341 (4 males), J35492 (1 male). Paratypes. Most collected by R.S. Wilson on RV Eastern Bass Strait, 8 km S of Wilsons Promontory lanaaroa using WIIOI epibenthie sled, Nov 1981. (39"12.9'S, I46°27.3'E), 65 m, medium sand (stn BSS Tasmania, western Bass Strait, 70 km W of (ape Fare- 180). NMV .18345 (1 male). 43 km SE of Port Albert well, King I., (39°38.2'S, 143°07.2'E), 127 m, mainly (38°53.7'S, I47°()6.5'E), 58 m, coarse shell (stn BSS sand (sin BSS 195) NMV .18340(1 male). Central Bass I 77), NMV .18342 (2 males). 50 km SE of Port Albert Strait,44kmNEofCapeWickham,KingI.(39°22.0'S, (38°54.3'S, 147°13.4'E), 58 m, coarse shell, Smith- 144°18.3'E), 60 m. coarse sand (stn BSS 203), NMV Mclntyre grab (stn BSS 176), NMV .18346 (1 male). .18348 (I male). 3.3 km S of Deal I. (39°48.3'S, Other material. 27 lots from 27-800 m depth in east- I47"19.2'E). 60 in, muddy sand, Smith-Melntyre grab ern Bass Strait and Tasmania, NMV collections. (sin BSS 161) NMV .18347 ( I male). 25 km SW ofCape Description. Total length of holotype: 5.08 1. 147°32.6'E). 51 I rankland. Flinders (4009.4'S, m, mm. shelly sand (stn BSS 1 62), NMV .18339 (4 males). East- Cephalosome roughly elliptical, 1.3 times as ern Bass Strait, 20 km SSW of Babel I. (40°06.8'S, 148'24.3'E), 22 m. coarse shell, Smith-Mclntyre grab long as wide, lateral margins slightly convex. (sin BSS 166), NMV .18.344 (3 males). 37 km NNE of Eyes well developed, lateral and sessile. Frontal Eddystone Point (40"4().7'S, I48"36.9'E), 67 m, border produced dorsally into rostrum; muddy sand (stn BSS 164), NMV .18338 (1 male). smoothly rounded, with 10 submarginal setae of Victoria. Western Bass Strait, 80 km WSW of Cape uniform size each side of mid-dorsal line. Exter- 94 m, coarse sand, Otway <39°59'S, 142'37'E), G.C.B. nal scissura absent. Supraocular lobe smoothly Poore on IIMAS Kimbla, 9 Oct 1980 (stn BSS 62), convex. Antennae subequal, downturned in lat- NMV .18343 (I male). 57 km SSW of (ape Otway eral view; flagellum of antenna 1 of 5 articles, (39"I7'S. I43°I4'E), 90 m. coarse carbonate sand. with 3 acsthctascs; flagellum G.C.B. I'ooreon HMASKimbla, lOOet I980(stn BSS of antenna 2 of 6 72)NMV.I8349(I male). Central Bass Slrail, 6km Sof articles. Mandible strongly curved, one-third Cape Schanck (38'33.4'S, I44°54.9'E), 55 m, medium length of cephalosome; with unarmed carina; sand (stn BSS I 54), NMV ,I8560( I male). 38 km SW of smooth blade. Maxilliped 5-articled, palp thin PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 329 Figure 34. Caecognathia leptanilla. Holotype, NMV J27562. 130 I1KIAN I ( Olll N AND GARY ( . I! POOR] Figure 15 Caecognathla leptanilla Holotype, NMV J27562 PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 331 Figure 36. Caeeognathia leptanilla. Holotype, NMV J27562; Dorsal view of cephalon of paratype, NMV J35492. and elongate; external margins of articles 2-4 setae laterally and pair of setae on distal apex. bearing plumose setae; endite clearly reaching Uropodal peduncle with 2 setae; rami subequal, article 3, wide. Pylopod 3-articled, internal mar- reaching apex of pleotelson, bearing numerous gin of plumose setae; article 1 with about 35 plumose setae. plumose setae on ventral surface; article 2 coni- Pereopods with dense cover of simple setae, cal, proximal margin completely joined to particularly on basis; with few lateral projections article 1 , with 6 setae on ventral surface; article 3 on anterior faces of ischium to carpus. Pereo- minute. pods 2 and 3 with broad basis. Pereon width increasing posteriorly; widest at Pleopods setose. Pleopod 2 endopod lacking pereonite 5, twice as wide as cephalosome; appendix masculina. Penes 2 small contiguous covered with fine, short setae. Pereonite 1 dor- papillae. sally reaching lateral margins, divided into 3 Distribution. Bass Strait and eastern Tasmania. of cephalosome and regions by posterior margin 27-800 m. partially obscured laterally by pereonite 2. Per- eonites progressively longer, except pereonite 2 Remarks. C. leptanilla is characterised by its and 3 subequal. Pereonite 6 posterior border produced rostrum. markedly indented; lobuii pronounced, globu- lar. Pereonite 7 very narrow, overlapping pleon. Caecognathia paratrechia sp. nov. Pleonites progressively longer; pleon tapered, Figures 37-39 pleonites 1 and 5 narrower than others; pleonal epimera prominent on pleonites 4 and 5. Pleo- Material examined. Holotype. South Australia, Pear- telson subtriangular, as wide as long, lateral mar- son I., Eside in bay (33°57.30'S, 134°l 5.70'E), 20 m, gins slightly sinuous; with 15 pairs of plumose bryozoans. sponges etc. on shaded surface, SCUBA, 332 BRIAN F. COHEN AND GARY C. B. POORE Figure 37. Caecognathia paratrechia. Holotype, NMV J27578. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 333 Figure 38. Caecognathia paratrechia. Holotype, NMV J27578. J34 BRIAN I COHEN AND GARY C. B. POORE Figure 39, Caecognathia paratrechia. Holotype, NMV .127578. l face article 2 conical, with 9-10 setae G.C.B. Poore, 17 Apr l )8.5(sln SA 55), NMV .127578 medianly; (I male), on ventral surface. Pereon widest posteriorly at pereonites 5 and Description, Total length of holotype: 3.67 6, 1.2 times as wide as cephalosome; covered mm. with numerous simple setae. Pereonite 1 dor- ( cphalosomc rectangular, 1.5 times as wide as sally reaching lateral margins and partially long, lateral margins slightly convex. Eyes well obscured laterally by pereonite 2. Pereonites 2 developed, lateral and sessile. Frontal border and 3 subcqual, as wide as eephalon. Pereonite 4 produced medianly, rounded with irregular bor- narrow; with anterior constriction; thin median der and median indentation; 3 long submarginal groove and posteriorly directed, bilobed exten- setae each side of median indentation. External sion of posterior border of pereonite 4. Pereon- scissura rounded. Supraocular lobe smoothly ite 5 and 6 rounded, similar to praniza but not convex, (ephalosome with many long simple fused. Pereonite 5 with areae latcrales. Pereonite setae and numerous granules; with mesial fur- 6 with lobi latcrales and rounded lobuii. Pereon- row and shallower, oblique posterior mesiola- ite 7 not visible. Pleotelson subtriangular, as leral furrows. Antennae subec|ual; llagellum of wide as long; lateral margins sinuous; with 5 antenna I of 5 articles, with 4 aesthelascs, article pairs of simple setae laterally. Uropodal ped- 3 of peduncle longer than llagellum or peduncle uncle without setae; rami rounded, subcqual, articles I and 2 together; llagellum of antenna 2 reaching just beyond apex of pleotelson, bearing of 5 articles, llagellum short, shorter than distal numerous plumose setae distally. article of peduncle. Mandible scoop-shaped, Pereopods with few simple setae; with many strongly curved, one-third length of cephalo- tubercles on ischium, merusand carpus, particu- some; with unarmed carina; armed mandibular larly on pereopod 4; pereopod 4 smaller than incisor one-third way along; slightly crenulate other pereopods. blade; setae at base of incisor and prominent Pleopods setose. Pleopod 2 endopod lacking quadrate internal lobe at base of mandible. appendix masculina. Penes 2 small contiguous Maxilliped 5-articled; external margins of papillae. articles 2-4 bearing plumose setae; endite Distribution. SA, rocky habitats, 20 m. clearly reaching article 3, narrow. Pylopod 2- arliclcd, internal margin of line short setae with Remarks. ( ' paratrechia is characterised by the 6-7 plumose setae on anteromesial margin; quadrate mandibular lobe and bilobed posterior article I operculate with 2.1 setae on ventral sur- projection on pereonite 4. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE J35 except Caecognathia trachymesopus sp. no v. blade on distal half; basal neck smooth projection for 1 rounded, posteriorly directed Figures 40-42 giving an uneven double-scalloped effect; Material examined, Holoiype. Tasmania, central Bass erisma pronounced, covering base of mandible. Strait, 20 km NNF of North Point (40"32.0'S, Maxillipcd 5-articled, palp thin and elongate; 145"23'E). 44 m. mnddy shell grit, Sniith-Mclntyre external margins of articles 2-4 bearing plumose grab, M.F. Ciomon and G.C.B. Poore on FV Sards, 4 setae; endite clearly reaching article 3, wide. (stn BSS 1 16). .127571 (I male). Nov 1980 NMV Pylopod 3-articled, internal margin of plumose Paratypes. Collected by M.F. Ciomon and (i.C.B. surface; setae; article 1 with 24 setae on ventral Poore on FV Santa. I 980, unless otherwise noted. Tas- article 2 conical, posterior margin completely mania, western Bass Strait, 55 km W of Stokes Point, joined to article 1, with 5 setae on ventral sur- King I. (40°06'S. 143°I6'E), 187 m. tine sand, Smith- face; article 3 minute. Melntvre grab. (i.C.B. Poore on IIMAS Kinihla, I 1 posteriorly; widest at Oct !980(stnBSS 101), NMV .18310(1 male). Central Pefeon width increasing mar- Bass Strait, 23 km F. of (ape Roehon, Three Hum- pereonite 5, twice as wide as cephalosomc; mock I. (40"22.2'S, 145°I7'E), 40 m, mainly sand. gins with numerous plumose selae. Pereonite I .17799 WHOI epibenthie sled (stn BSS I 12), NMV (2), dorsally reaching lateral margins, divided into 3 North NMV J7798 (2). 20 km NNH of Point regions by posterior margin of cephalosomc and <40"32.0'S, I45°23'E), 44 m, muddy shell grit, Smith- partially obscured laterally by pereonite 2. Pcr- Melnlyre grab (stn BSS 116), NMV .177% (8). eonites progressively longer; pereonite 6 pos- (40'23.8'S. I45°32'E), 66 m. muddy sand, Smith- terior border markedly indented; lobuii pro- Melnlvre grab (stn BSS 113), NMV J7797 (2). 33 km S nounced, globular. Pereonite 7 very narrow, of Deal F, (39°48.3'S, 147°19.3'E), 60 m, muddy sand, pleon. Pleon with pleonitcs sube- WHOI epibenthie sled, R.S. Wilson on RV TangarOO, overlapping others. Pleo- 14 Nov 1981 (stn BSS 161), NMV .18304 (1). qual, pleonite 5 slightly longer than Victoria. Western Bass Strait, 25 km WSW of Cape telson subtriangular, as wide as long; lateral Otway (38°55'S. 143°25'E), 67 m, medium sand, natu- margins sinuous; with 8 pairs of plumose setae Oct ralists' dredge. (i.C.B. Poore on HMAS Kimhla, 8 laterally and pair of setae on distal apex. Uropo- .18309 Central Bass 1980 (stn BSS 53), NMV (1). dal peduncle with 2 setae; endopod longer than 60 SW of Cape Schanek. (39°00.2'S, Strait. km exopod, not reaching apex of pleotelson; 144'33.9'E), 74 m. sandv shell, R.S. Wilson on RV internal margins of rami bearing numerous plu- Jangaroa, 23 Nov 1981 (sin BSS 202), NMV .18307 Entrance, mose setae. (2). Eastern Bass Strait, 40 km SSW of Fakes Basis to carpus of pereopods with dense cover Victoria (38°I8.0'S, 147°37.0'E), 55 m, muddy fine setae, particularly on basis; with few shell, M.F. (iomon and R.S. Wilson on FV Silver Gull, of plumose of ischium to 31 Jul 1983 (stn BSS 209), NMV .18301 (4). Eastern lateral projections on anterior face 21-45 Bass Strait, between LakcTyersand I'l Rieardo, carpus. m sandv sediments, Sep 1990, MSF-FXi stns, 10 lots: Pleopods setose. Plcopod 2 endopod lacking .124638 ( 1 ), 124637 ( ), NMV J24693 (3), NMV contiguous NMV I appendix masculina. Penes 2 small 126358(1), NMV.126359 (2). NMV 124695(3). NMV. papillae. ( ), NMV ,124640 ( 1 ), ( ). V .124694 I NMV ,126360 I NM NMV .124691 (3). Distribution. Bass Strait, 27-293 m. Bass Strait, 27-293 m Other material. 1 I lots from Remarks. Caecognathia trachymesopus is simi- depth, NMV collections. lar to C. diacamma but is differentiated by the of holotype: 3.23 Description. Total length less produced frontal border, narrower and mm. longer cephalosomc, more complex mandible 1.3 times as Brown. Cephalosomc elliptical, and the lack of lateral sutures on pereonite 6, convex. long as wide, lateral margins slightly and sessile. Frontal Eyes well developed, lateral Elaphognalhia Monod small border slightly produced, rounded with median indentation; with 9 submargmal setae- Gnathia (Elaphognuthia) Monod, 1926: 558-560. decreas- - - Bacescu, 1960: each side of indentation, setae generally — Gurjanova. 1936: 256-257. very shal- 107-112. — Cals, 1973: 295, 305. -- lloldiehand ing in size laterally. External scissura Anten- Harrison, 1980: 218. low. Supraocular lobe smoothly convex. 1 slightly longer than nae down-turned; antenna Type species. Anceusferox Haswcll, 1 885 (herein 1 ol 5 articles, antenna 2; flagellum of antenna designated). ol 4 with 3 aesthetascs; flagellum of antenna 2 hall length ol Diagnosis. Eyes present. Frontal margin of articles. Mandible strongly curved, smooth cephalon transverse, deeply excavated; with cephalosomc; with unarmed carina; BRIAN I COHEN AND GARY C B POORE v ( / . / ) l \ V i/i r /// . /fl! f ''(/''/• r}'^ J({Sf 7 1\ ' t \ k "^ I .' /*< igure 40 I '«<*i ORnalhta Itat hytwxopus I i<i\ pc, nm\ i / 1 PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 337 Figure 41. Caecognathia trachymcsopus. Holotype, NMV J27571. . h 3 338 BRIAN F. COHEN AND GARY C. B. POORE Figure 42. Caecognathia trachymesopus. Holotype, NMV J2757F frontal processes which may be emarginate. Australian species is designated here and the Mandibles long, cylindrical; often lacking man- name elevated to generic rank, dibular blade though may pocess numerous Species of Elaphognat ware most easily rec- specialised structures. Pereonitc I immersed in ognised by the excavate frontal border and the cephalon. Pylopod 2- or 3-articled; opcrculatc, elongate mandibles lacking any dentate blade, article I enlarged, generally with dense external The genus was described as Indopacific by margin of plumose setae; article 3 small or Gurjanova (1936) and Bacescu (1960) and absent. in Tethyan origin by Cals ( 1 973). There are 1 species distributed through the Indo-West Remarks. The subgenus Elaphognathia was Pacific and Mediterranean. Of the five species erected by Monod (1926) for four species but known from Australia, one is newly described, none was selected as type species, then or since. The other four are briefly illustrated (see figs As the first described Elaphognathia, Haswell's 2N-Q). Key to males of Australian species of Elaphognathia 1 Supraocular lobe extended dorsally as crest, pereonites 5-6 fused as in pran- zia sta c S E. rimifrons Supraocular lobe — not extended dorsally as crest, pereonites 5-6 not fused 2 2. Mandibles almost twice as long as cephalon, pcrconite 1 obvious, pylopods without aerolae 3 Mandibles as long as cephalon, pereonite 1 not visible, pylopods with aero- lae 4 3. Mandibles with conical internal lobe at base, without small internal notch behind tip; mcdiofrontal process with 3 setae either side of median notch and not produced beyond base of mandibles £. froygattella Mandibles with large quadrate internal lobe at base and small internal notch behind tip; mediotrontal process produced beyond base of mandibles with 2 acute lateral projections, no setae £ bifunilla PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 339 4. Mandibles cylindrical, with 2-3 apical cusps; cephalon without low median tubercle; pylopod 3-articled, with 2 plumose setae on anterior margin of article 1 (NB: specimens can lack the slight median projection found at the base of the rounded excavation of the frontal border, a characteristic used in previous keys) E. ferox — Mandibles with small blade, lacking apical cusps; cephalon with low median tubercle; pylopod 2-articled, article 1 with many plumose setae on margin E. forceps Elaphognathia froygattella sp. nov. long, lateral margins sinuous; with 3-5 pairs of simple setae. Uropodal peduncle with 3 setae; Figures 43-45 rami subequal, reaching beyond the apex of Material examined. Holotvpe. Victoria, western Bass pleotelson, bearing numerous plumose setae dis- Strait. 35 km SSW of Cape Otway (39°07.0'S, tally. 143°14.6'E). 84 m. coarse sand, WHOI epibenthic Pereopods progressively longer, with dense sled, R.S. Wilson on RV Tangaroa. 20 Nov 1981 (stn cover of simple setae. Pereopod 6 with one BSS 183). NMV J27568 (1 male). anterior spiniform seta on merus, Paratypes. Type locality. NMV .18374 (2 males). Pleopods setose. Pleopod 2 endopod lacking Description. Total length of holotype: 5.09 appendix masculina. Penes 2 small contiguous mm. papillae. Cephalosome rectangular, twice as wide as Distribution. Western Bass Strait, 84 m. long, lateral margins convex. Eyes well devel- oped, lateral and sessile. Frontal border deeply Remarks. Elaphognathia froygattella is most excavated mid-dorsally: mediofrontal process similar to E. bifurcilla Holdich and Harrison inferior, ventral to excavation, conical with from North Queensland, particularly in overall large median notch, with 6 setae spread across body proportions; the great length of the mandi- base of notch; superior frontolateral process bles and their more lateral attachment. E. froy- acute, directed antcrolaterally, located at base of gattella differs from E. bifurcilla in the smaller mandible, with 4 evenly spread setae on both emarginate mediofrontal process, absence of an margins. Inferior frontolateral process acute. internal notch near the tip of the mandible and External scissura very shallow. Supraocular lobe the different internal mandibular lobe. very low, acute. Antenna 1 directed ventrally in lateral view; flagellum of 5 articles, with 4 aes- thetascs. Antenna 2 twice as long as antenna 1; Euneognathia Stebbing flagellum of 7 articles. Mandible straight, twice Euneognathia Stebbing, 1893: 338. — Monod. cylindrical, with no as long as cephalosome; 1926: 312-313 (and other authors). obvious blade; with unarmed carina and 2 coni- species. Anceus gigas Beddard, 1886 cal internal lobes; distal lobe, one-third way Type along, directed anteriorly; proximal lobe, at base (monotypy). Maxilliped 5- of mandible, directed posteriorly. Diagnosis. Eyes present. Frontal margin of palp articled, endite clearly reaching article 3; cephalon not produced; transverse, with frontal external broad with articles 2-5 wider than long, processes. Mandibles with blade and pseudo- Pylopod 3- margins bearing plumose setae. blade. Cephalon with paraocular ornamen- 1 with 4 setae on ventral surface articled; article tation. Pereonite 1 immersed in cephalon. Pos- bearing plu- medianly, distal internal margin terior margin of pereonite 6 deeply excavated with 3 setae on mose setae; article 2 circular for pleon. Pylopod 5-articled; not operculate, ventral surface distally; article 3 minute. with dense external margin of plumose setae. Pereon evenly sided, as wide as cephalosome, Remarks. Euneognathia is a monotypic genus margins with numerous setae. Pereonite 1 barely found around Antarctica (Schultz, 1978). It is reaching lateral margins dorsally, partially the only genus of Gnathiidae with the combi- obscured laterally by pereonite 2; pereonites 2 nation of frontal processes and a 5-articled, non- and 3 subequal, 4 wider than 5 and 6. Pereonite 7 operculate pylopod. Euneognathia gigas is a not visible. Picon broad, epimera prominent. very large species, males being greater than 10 Pleonites 2-4 subequal, pleonite 5 shorter than mm long. The species' status as member of a others. Pleotelson subtriangular, wider than B. POORE 340 BRIAN F. COHEN AND GARY C. Figure 43. Elaphognathia froygattella. Holotypc, NMV J27568. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 341 Figure 44. Elaphognathia froygattella. Holotype, NMV J27568. B. POORE F. COHEN AND GARY C. 342 BRIAN Figure 45. Elaphognathia froygattella. Holotype, NMV J27568. europalothrix. It is most easily distinguished monotypic genus is supported by the phylogen- from other Gnathiidae by the large anteriorly etic analysis. directed projection orginating dorsally from per- Gibbagnathia gen. nov. eonite 3. Gibbagnathia and Thaumastognathia both have reduced maxillipeds and small, pedi- europalothrix sp. Type species. Gibbagnathia form pylopods but differ largely in the shape of nov. the pereon and mandibles. Diagnosis. Eyes present. Frontal border slightly Gibbagnathia europalothrix sp. nov. produced. Mandibles simple, lacking distinct peduncle. Mouth- blade. Antenna 1 with stout Figures 46, 47 parts small; pylopod pediform and maxilliped of Material examined. Holotype. Tasmania, eastern Bass 2 articles. Pereon rectangular, with numerous Strait, 30 km N of North Point. Flinders I., (39°26.3'S, setae and small granules; pereonite 3 with large 147°48.7'E), 49 m, medium sand, WHOI epibenthic anteriorly directed projection; pereonite 7 vis- sled, R.S. Wilson on RV Tangaroa, 17 Nov 1981 (stn with prominent epimera. ible. Pleon wide, BSS 173). NMV J8366 (1 male). Paratvpes. Tasmania, western Bass Strait, 48 km Etymology. From gibba (Latin), meaning a NNW of Cape Farewell, King I. (39°22'S, 143°28'E), hump, referring to the dorsal prominence on 104 m, medium sand, carbonate, G.C.B. Poore on pereonite 3 and Gnathia. HMASA'/wWa, lOOct 1980(stn BSS 78), NMV J8369 King I. (39°20'S, Remarks. Gibbagnathia is a monotypic genus (2). 47 km NW of Cape Farewell, 143°34'E), 95 m, coarse sand, carbonate, G.C.B. Poore confined to Bass Strait, the only species being G I'HYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 343 S Kimbl l0 ct ^ ° '980 (stn BSS 77) NMV lateral ?o«„ margins sinuous with 1 J8368 ( male). pair of simple 1 Central Bass Strait, 44 km NE of Cane setae Wickham, King laterally and pair of setae on distal apex. I. (39°22.0'S. 144°18 3'E) 60 m coarse sand. Uropodal peduncle without R.S. Wilson on RV Tangarao, 23 Nov setae; endopod 1981 (stn BSS twice as long as exopod, reach 203), NMV J8365 (1 male). Eastern ing beyond apex of 3 km N of North Point pleotelson; rami bearing numerous plumose ° - binders I (39ESSlS^26.3 S. 147'48.7'E), 49 m, medium sand, Smith- setae distally. Mel ntyre grab. R.S. Wilson on RV Pereopods Tangaroa, 1 7 Nov with moderate cover of plumose 1981 (stn BSS 173), J8367 NMV (1 male) and simple setae, plumose setae confined mainly Victoria. Western Bass Strait. 30 km SSW of Warr- to basis and ischium; pereopods 2 and 6, larger nambool, (38°38.2'S. 142°35.0'E). 59 m, WHOI epi- than pereopods 3-5, with setae benthic sled. R.S. Wilson on scales on RV tangaroa 20 Nov ischium. 1981 (stn BSS 188), NMV J8370 (1 male). Eastern Bass Strait, Pleopods setose. Pleopod 2 endopod lacking 19.1 km W of Pt Ricardo (37°50.57'S appendix masculina. Penes 148°25.02'E), 36 m. sand-shell. Smith-Mclntyregrab fused as 1 small Marine papilla. Science Laboratories on FV Sarda ~>6 Sep 1990 (stn MSL-EG 43), NMV J24633 (1 male). Distribution. Bass Strait, 36-104 m depth. Remarks. G. europalothrix has similar Description. Total length of holotvpe: 2.03 mouth- mm. parts to species of Thaumatognathia but differs by possessing a rectangular pereon with a deeply Cephalosome rectangular, 2.4 times as wide as concave posterior border, long, lateral margins straight. Cephalosome and straight pleon with pronounced epimera and straight mandibles anterior pereon covered with numerous setae. without a distinct blade. G. europalothrix Eyes well developed, lateral and sessile, not eas- is most easily identified by the very large anter- ily visible dorsally. Frontal border slightly pro- iorly directed projection on pereonite 3. duced medianly, with 6 setae submarginalfy, in 2 clumps of 3. Lamina dentata visible, external Gnathia Leach scissura very shallow. Supraocular lobe not pro- Gnathia Leach. nounced dorsally, raised in lateral view as dis- 1814:386.402. — Monod. 1926: 326-329 (part) and numerous tinct projection. Antennae stout, antenna 2 other authors. Anceus longer than Risso. 1816: 8 (type species: Anceus forfwu- antenna 1; flagellum of antenna 1 of laiius Risso. 1816). 4 articles, with 3 aesthetascs, peduncle articles Praniza Latreille. 1817: 54 (type species: Oniscus slightly rounded; flagellum of antenna 2 of 5 marinys Slabber, 1778). articles. Mandible located on median projec- Zuptwa Risso, 1826: 1 04 (type species: Zttphea spar- tion; close set, straight; half length of cephalo- icola Risso, I 826). some: dorsoventrally flattened; thin and flexible Gnathia (Gnathia) s.s. — Monod. 1926: 329 in preserved specimens without obvious blade (part). Gnathia or features, raised in lateral view. Maxilliped (Perignathia). — Monod. 1926:554-555 (not Perignathia Monod, 1922). very reduced, of 2 articles with 4 setae distally. Pylopod thin, elongate, 4-articled, all with seta, Type species. Gnathia termitoides Leach, 1814 terminal article minute. (= Cancer maxillaris Montagu, 1 804) (mono- Pereon evenly sided, as wide as cephalosome, typy) covered with numerous simple setae except for Diagnosis. Eyes usually present. Frontal margin pereonite 5. Pereonite 1 dorsally small, not of cephalon generally reaching lateral margins and partially obscured transverse, with frontal processes. Mandibles usually with laterally by pereonite 2. Pereonite 2 slightly pro- dentate man- dibular blade and mandibular incisor. duced anterolaterally. Pereonite 3 with large, Cephalon may possess paraocular distinct anteriorly directed, bilobed projection ornamentation and/or a dorsal sulcus. Pereonite 1 immersed in cepha- partially overhanging pereonites 1 and 2. Per- lon. Pylopod 2- or 3-articled; eonite 4 with narrow anterior constriction. Per- operculate, article 1 enlarged, generally with eonite 6 posterior border deeply concave, with dense external margin of plumose setae; article 3 small large extensions lateral to pleon. Pereonite 7 or absent. very narrow, overlapping pleon. Pleon wide Remarks. The genera Anceus. Praniza, and except pleonite 1 which is constrained by per- Zuphea. are all based on European gnathiid lar- eonite 6; pleonite 2 three-quarters width of per- val stages whose specific identities are imposs- eon; plconites 3-5 decreasing in width poster- ible to confirm (Monod, 1926). They have iorly. Pleotelson subtriangular. wider than long. therefore traditionally been treated as junior M4 BRIAN F. COHEN AND GARY ('. 1?. POORE Figure 46. Gibbagnathia europahthrix. Holotype, NMV J8366. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 345 * >r^o- Figure 47. Gibbagnathia europalothrix. Ilolotypc, NMV .18366. C. B. POO RE 346 BRIAN F. COHEN AND GARY member of Gnathia s.s. The type species is there- synonyms of Gnathia and, in the case of Praniza, gna- fore subject to dispute and can only be decided as the name for the larval stage of all by reference to the ICZN. As long as the name is thiids. viewed as a junior synonym its type species is of Our concept of Gnathia is narrower than that further com- treated as little consequence. Monod (1926) of Monod ( 1 926). A fifth generic name plicated the issue by excluding both potential a junior synonym by him, Caecognathia Dollfus, type species from Perignathia and using it as a 1901, is herein revived for a monophylctic group name for another, Gnathia triospa- of species once placed in Gnathia but now con- subgenera thiona Boone, 1918. If this species were to war- sidered the sister taxon of Gnathia + Elaphogna- rant generic or subgeneric status it would require thia. Wagele (1987) proposed that llcterogna- a new generic name but our analysis suggests thia Amur and Roman, 1974 is a junior synonym is not so. of Gnathia but with the restriction of the generic that this Gnathia is the largest genus in the family concept it becomes a junior synonym of Caecog- whose species are recognised by the possession nathia instead. 2- 3-articled pylopod, presence of Elapkognathia Monod, 1926, hitherto a sub- of a broad or frontal processes, a straight frontal border, and genus, is elevated to generic rank. non-elongate mandibles with dentate blade. We Perignathia Monod, 1922 is problematical arc unable to find a unifying synapomorphy of name. It was erected as a genus for Anceus aby.s- but treat it as a paraphyletic taxon sorutn Sars, a species we believe to be a member Gnathia exclusion of species of the mon- of Caecognathia Dollfus and could therefore be formed by the ophylctic Elaphognaihia from a larger clade. its junior synonym. Later, Monod (1926) Australia have already been admitted that the material on which he based his Eleven species from are briefly figured generic diagnosis was not Sars' species and he described (see Table 5) and (see fig. 2). reidentified it as Gnathia fallax Monod, 1926, a Key to males of species of Gnathia from Australia 1. Ccphalon with a very large tubercle in anterior midline and 2 smaller tubercles near base of the mandibles. Paraocular ornamentation a single tubercle anterior to oblique ridge Of 3 small tubercles G. mulieraria — Ccphalon not so 2 2. Penes fused and produced 3 — Penes not fused and produced 4 3. Penes very large, directed posteriorly; mediofrontal process sharply conical; pylopod 2-articled with 3 areolae on article 1 G. falcipenis — Penes small, directed anteriorly; mediofrontal process rounded with 2 setae each side; pylopod 3-articled, with 2 areolae G'. epopostriuna 4. Dorsum dived by shallow grooves marked by lines of chromatophorcs; parao- cular ornamentation as a mediolateral ridge, eyes overhanging in lateral view G. cornuta — Ccphalon not so 5 5. Pleopods unequal, anterior pair naked, 2-3 times the size of the 3 setose posterior pairs G. variobranchia — Pleopods subequal 6 6. Paraocular ornamentation present 7 — Paraocular ornamentation absent 13 7. Pylopod lacking internal margin of plumose setae, length greater than twice width 8 — Pylopod with internal margin of plumose setae, length about twice the width 9 IMIYI (Kil-NY AND BIOGEOGRAPHY OFGNATHHDAE 347 8. Superior frontolatcral process large and circular, lacking setae; mandibular blade slightly crenulate Q. prolasius Superior — frontolatcral processes small and conical, with many setae; man- dibular blade smooth (,- stigmacros 9. Inferior frontal border relatively straight, crenulate G. mclicola — Frontal border with mediofrontal process 10 10. Paraocular ornamentation extremely pronounced, particularly in lateral view; frontal border produced; maxillipedal endile narrow . G. notostigma — Paraocular ornamentation not extremely produced; frontal border at most only slightly produced; maxillipedal endite broad II 11. Mandibles slightly asymmetrical, lacking incisor, less than half length of cephalon; mediofrontal process superior; percon without anterior constric- tion on peronite 4 (;. calamitosa — Mandibles symmetrical, with incisors, greater than half length of cephalon; mediofrontal process inferior; pereon with anterior constriction on peronite 4 12 12. Cephalon and anterior percon with granules; mandibles with pscudobladc; pylopod with areolae; mediofrontal process conical with many notches on lateral margins (/. campontus — Cephalon and pereon without granules; mandibles lacking pscudobladc; pylopod with areolae; mediofrontal process truncate; dorsal sulcus on peron- ite 5 (/. hiorhis 1 3. Mandibles without incisors 14 — Mandibles with incisors 17 1 4. Frontal border produced 15 — Frontal border not produced 16 15. Mandibles with dorsal lobe; frontal border lacking setae . (i. rhylidoponcra — Mandibles without dorsal lobe; frontal border with 8-9 setae in row, each side of mediofrontal process G. halci 90°; 16. Peronite 1 not visible; mandibles inflected upwards at mediofrontal pro- cess bifid; sparsely setose G. mystrium trifid; — Peronite I visible; mandibles not inflected; mediofrontal process heavily setose G. iriclomyrmcx 1 7. Mediofrontal border smooth G. asperifrons — Mediofrontal border of cephalosomc, between mandibles, markedly toothed or notched '8 18. Mediofrontal process trifid, half length of superior frontolatcral process G. calmani — Mediofrontal process a single projection, as long as superior frontolatcral processes 19 19. Mandible with mandibular seta, lacking pseudobladc; pleopods without setae; dorsally setose; pereon without granules; cephalon rectangular G. odontomachus Mandible lacking mandibular seta, with pscudobladc; pleopods setose; not dorsally setose; cephalon and anterior pereon with granules; cephalon qua- latidem drate G- B. POORE 348 BRIAN F. COHEN AND GARY C. of plumose setae; article 1 with 3 (i nut hia camponotus sp. no v. internal margin areolae along internal margin, with 13 setae dis- Figures 48-50 tally on ventral surface and along external mar- setae distally on ventral Material examined. Holotype. Tasmania, eastern Bass gin; article 2 with 4 Strait, 100 km NE of North Point, Flinders I. surface; article 3 minute. (38*52.6'S, I48"25.2'E), 130 m, line sand, WHO] cpi- Pcreon evenly sided, as wide as ccphalosome. sled, R.S. Wilson on RV TangCtroa, 15 Nov margins, benthie Pcreonite 1 dorsally reaching lateral 1981 (stn BSS 170), NMV .127566 (I male). divided into 3 regions by posterior margin of Type locality, J8322 (20 males). 37 Paratypes. NMV ccphalosome and partially obscured laterally by km NNE orEddystone Point (40°40.7'S, I48°36.9'E), pereonitc 2 and cephalon. Pereonites 2 and 3 67 m, muddy sand, WHO] epibenthic sled, R.S. Wil- subequal; 4 with anterior constriction; 5 and 6 son on RV Tnngaroa, 14 Nov 1981 (stn BSS 164), than others together. Pereonite 7 NMV J8327 (3 males). 70 km ENE of North Point, together longer pleon. Pleonites pro- Flinders 1. (39°28.4'S, 148°4I.8'E), 110 m, coarse very narrow, overlapping sand, naturalists' dredge. G.C.B. Poore on HMAS gressively narrower after plconite 2, pleonal epi- KlmMa, 28 Mar 1979 (stn BSS 35), NMV .18331 (I). mcra prominent on pleonites 4 and 5. Pleotclson Victoria, eastern Bass Strait, 43 km SE of Port subtriangular, as wide as long, with 2 pairs of 147°06.5'E). 58 m, coarse shell. Albert (38°53.7'S. simple setae and pair of setae on distal apex. Smith-Mclntyre grab, R.S. Wilson on RV Tangaroa. Uropodal peduncle with 3 setae; rami subequal, 1 8 Nov 1 98 1 (stn BSS 1 77), NMV .18323 (3). 50 km SE reaching apex of pleotclson; rami bearing Of Port Albert (38°54.3'S. I47°13.4'E). 58 m, coarse numerous plumose setae distally. shell, WHO) epibenthic sled. R.S. Wilson on RV Icin- of typical gnathiid form with few Uiiroa. 18 Nov 1981 (sin BSS 1 76), NMV .18330(3). 40 Percopods km SSW of Lakes Entrance(38°18.0'S, I47°37.0'E), 55 simple setae. m, muddy line shell. WHOl epibenthic sled, M.E. Plcopods setose. Pleopod 2 endopod with Cionion and R.S. Wilson on FV Silver Gull, 3 I Jul 1983 appendix masculina half length of rami. Penes 2 (sin BSS 209), NMV .18328 (3). small contiguous papillae. Other material. Bass Strait. 44- 1 I 5 m. NMV .18325 ( ). .18332(4). .18329(2); Distribution. Strait, 55-130 depth. I NMV.18324 (7); NMV NMV Bass m NMV .18326(2), Remarks. This species most closely resembles G. Description. Total length of holotype: 3.36 latidens (Beddard) from north-eastern Aus- mm. tralia. These two species are characterised by an Ccphalosome quadrate, lateral margins con- inferior conical mediofrontal process which is vex. Numerous very fine granules on ccphalo- wider than long and a smaller superior frontola- some and anterior pcreon. Eyes well developed, teral processes. lateral and sessile. Frontal border transverse; G. camponotus differs from G. latidens in pos- mediofrontal process inferior, conical with sessing a regularly notched mediofrontal pro- marked notches and 2 long setae laterally; cess, a small tubercle on the posterior cephalon superior frontolateral process smoothly conical, and paraocular ornamentation. half length of mediofrontal process. Lamina denlata visible. External scissura very shallow. Gnathic, epopostruma sp. nov. Supraocular lobe not pronounced, ventral Figures 51-53 accessory supraocular less rounded. Ccphalo- some with broad dorsal sulcus; paraocular Material examined. Holotvpe. Victoria, western Bass tubercles and setae; with small posterior median Strait, 44 km SW of Cape Otway <39°06.3'S. tubercle at base of sulcus; with translucent ellip- I42"55.6'E), 81 m. medium sand, R.S. Wilson et al. on tical region anteromedianly, above buccal cav- RV Tangaroa, 21 Nov 1981 (stn BSS 192). NMV .18373(1 male). ity. Antenna 2 longer than antenna 1; flagellum of antenna 1 of 5 articles, with 2 aesthetascs; fla- Description. Total length of holotype: 3.83 gellum of antenna 2 of 7 articles. Mandible mm. straight, two-thirds length of ccphalosome: with Specimen damaged, missing left mandible unarmed carina; slight mandibular incisor half- and slightly deformed. Cephalosome quadrate, way along; ventral dentate blade on distally half, lateral margins straight. Eyes well developed, with smooth pseudoblade dorsally; internal lobe lateral and sessile. Frontal border produced; on proximal half a long crcnulate lamina; basal mediofrontal process superior, rounded with 2 neck short. Maxilliped 5-articled: external mar- setae laterally; superior frontolateral process gins of art iclcs 2-4 bearing plumose setae; endite conical, with 4-5 setae on external margin. barely reaching article 3. Pylopod 3-articlcd. External scissura very shallow. Supraocular lobe PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 349 Figure 48. Gnathia camponotus. Holotype, NMV J27566. 350 BRIAN F, COHEN AND GARY C. B. POORE P3 l Figure 4 >. Gnathia camponotus, Holotype, NMV J27566. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 351 Figure 50. Gnathia camponolus. Holotype, NMV J27566. not pronounced. Cephalosome with short, broad Pleotelson subtriangular, as wide as long, lateral dorsal sulcus; crenulate paraocular ridge par- margins sinuous; with 3 pairs of simple setae and tially obscuring eyes. Antennae normal; antenna pair of setae on distal apex. Uropodal peduncle 2 twice as long as antenna 1; flagellum of with 4 setae; rami subequal, reaching beyond of antenna 1 of 5 articles, with 1 aesthetasc; flagel- apex of pleotelson; internal margins rami lum of antenna 2 of 7 articles. Mandible raised bearing numerous plumose setae. distally, subequal to length of cephalosome; with Percopods subequal, with moderate cover of long, acute apex, one-third length of mandible; simple setae; pereopod 2 with 1 posterior pecti- unarmed carina and lacking incisor; seta at mid- nate seta on carpus; posterior margin of merus of point; with crenulate blade in middle third; pereopods 5 and 6 with row of short, fine proximally with internal lobe a crenulate lam- setae. ina; basal neck obvious. Maxilliped 5-articled; Pleopods setose. Pleopod 2 endopod lacking external margins of articles 2-4 bearing plumose appendix masculina. Penes prominent, present setae; maxilliped endite clearly reaching article as 2 large papillae. 3, narrow. Pylopod 3-articled, internal margin of Distribution. Western Bass Strait, 8 1 m depth. plumose setae; article 1 with 2 small areolae and is similar 8 setae on ventral surface, 6 distally; article 2 Remarks. Gnathia epopostruma most Harrison. with 8 setae on ventral surface; article 3 min- to G. fa/eipenis Holdich and Both species possess a trifid, produced frontal border; ute. Pereon widest anteriorly, as wide as cephalo- raised paraocular ornamentation and similarly some; covered with numerous simple setae. proportioned cephalon and pereon. G. epopos- lateral truma differs in having a rounded, not sharply Pereonite 1 dorsally small, not reaching mediofrontal process; a more hirsute margins and partially obscured laterally by per- conical habitus; paraocular ornamentation which over- eonite 2. Pereonite 2 and 3 subequal; pereonite 4 hangs the eyes; and smaller, though still with anterior constriction; pereonite 6 longest. anteriorly directed penes. The penes of Pereonite 7 very narrow, overlapping pleon. enlarged, Jalcipensis are posteriorly directed. Pleonites subequal, pleonal epimera prominent. G. 352 BRIAN F. COHEN AND GARY C. B. POORE Figure 51. Gnathia epopostruma. Holotype, NMV J8373. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 353 Figure 52. Gnathia epopostruma. Holotype, NMV J8373. B. POORE 354 BRIAN F. COHEN AND GARY C, Figure 53. Gnathia epopostmma. Holotype, NMV J8373. Gnathia iridomyrmex sp. nov. unarmed carina; without incisura; seta at mid- point, irregularly crenulate blade on proximal Figures 54-56 two-thirds with short basal neck. Maxilliped 5- Material examined. Holotype. Victoria, Saxon Reef, articled; external margins of articles 2-4 bearing Portland (38°18.5'S, 141°38.5'E), 11 m, red coralline plumose setae; endite barely reaching article 3. airlift, Wilson, 5 1992 (stn alga turf. SCUBA R.S. Mar Pylopod 3-articled, internal margin of plumose CRUST 178), NMV .127572 (1 male). setae; article 1 with 3 areolae and 3 setae on ven- Description. Total length of holotype: 2.52 tral surface distally; article 2 with 4 setae on mm. ventral surface; article 3 minute. Preserved specimen dark brown. Cephalo- Pereon widest anteriorly, as wide as cephalo- some rectangular, 1.15 times as wide as long, some; covered with numerous plumose setae. lateral margins slightly convex. Eyes well devel- Pereonite 1 dorsally small, not reaching lateral oped, lateral and sessile. Frontal border trans- margins and partially obscured laterally by per- verse. Mediofrontal process inferior, broad, tri- eonite 2. Pereonite 2 and 3 subequal; pereonite 4 fid. Superior frontolateral process acute, narrower than others, with anterior constriction; directed anterolaterally, twice length of medio- pereonite 5 and 6 longest. Pereonite 7 very nar- frontal process with 4 setae evenly spaced on row, overlapping pleon. Pleonite 5 shorter than internal margin. External scissura rounded. others, pleonal epimera prominent. Pleotelson Supraocular lobe not pronounced. Cephalosome subtriangular, as wide as long; lateral margins with small dorsal sulcus; translucent elliptical sinuous; with 3 pairs of simple setae and pair of region antcromedial above buccal cavity. setae on distal apex. Uropodal peduncle with 2 Antenna 2 longer than antenna 1; flagellum of setae; rami subequal, reaching beyond apex of antenna 1 of 5 articles, with 3 aesthetascs, distal pleotelson; internal margins of rami bearing peduncle article longer than 2 proximal articles; numerous plumose setae. flagellum of antenna 2 of 7 articles. Mandible Pereopods subequal, with moderate cover of straight, two-thirds length of cephalosome: with simple setae and crenulate anterior margin of PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 355 Figure 54. Unalhia iriclomyrmex. Hololype, NMV ill 512. 356 BRIAN F. COHEN AND GARY C. B. POORE Figure 55. Gnalhia iridomyrmcx. Holotype, NMV J27572. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 357 Figure 56. Gnathia iridomyrmex. Holotype. NMV J27572. basis; pereopod 6 with 2 anterior pectinate setae son on RV Tangaroa. 22 Nov 1981 (stn BSS 198), NMV J27564 (1 male). on merus: pereopods 2 and 6 with 1 posterior Paratypes. All collected by R.S. Wilson on RV Tan- seta on carpus. garoa, Nov 1981. Western Bass Strait, type locality, Pleopods setose. Pleopod 2 endopod with NMVJ8352(1). 20 km SSW of Stokes Point, King I. appendix masculina half length of rami. Penes 2 (40°I9.5'S, 143°48.8'E), 71 m, sandy shell (stn BSS small contiguous papillae. 199). NMV J8351 (1). Eastern Bass Strait, 25 km NE of Deal I., Tasmania Distribution. Western Victoria, rocky substrate, (39°14.8'S, 147"31.5'E), 57 m, medium sand (stn BSS 1 1 m depth. 174), NMV J8353 (1). 100 km NE of North Point, Remarks. Gnathia iridomyrmex most closely Flinders I. (38°52.6'S. 148°25.2'E), 130 m, fine sand (stn BSS 1 J8354 ( ). 37 km NNE of Eddys- resembles G. calmani Monod in the shape of the 70), NMV 1 tone Point (40°40.7'S, 148°36.9'E), 67 m, muddy sand mediofrontal process, though in G. iridomyrmex (stn BSS 164). NMV J8350 ( 1 ). the mediofrontal process is broader (half the width of the cephalon versus one-third the Description. Total length of holotype: 3.07 G. iridomyrmex also differs in being hir- width). mm. sute; lacking mandibular incisors, the posterior Cephalosome quadrate, large, one-third tubercle on the cephalon and anterolateral lobes length of animal, lateral margins convex. Eyes on pereonite 4. G. iridomyrmex is also similar to well developed, lateral and sessile. Frontal bor- G. odontomachus but differs in possessing a tri- der slightly produced; mediofrontal process fid mediofrontal process, more pronounced inferior, broad with bifid projection; superior superior frontolateral processes and a simpler frontolateral process conical, with 3 setae on mandibular blade. internal margin. Inferior frontolateral process conical, ventral to superior frontolateral pro- Gnathia mystrium sp. nov. cess. External scissura very shallow. Supraocular Figures 57-59 lobe very low, acute. Cephalosome with broad dorsal sulcus; paraocular tubercles and setae; Material examined. Holotype. Tasmania, western translucent elliptical region anteromedially, Bass Strait, 36 km SSW of Stokes Point, King I. R.S. Wil- above buccal cavity. Antenna 2 longer than (40°26.7'S. 1 43°4I .4'E), 85 m, medium sand, 358 BRIAN F. COHEN AND GARY C. B. POORE Figure 57. Gnathia mystrium. Holotypc, NMV .127564. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 359 Figure 58. Gnathia mystrium. Holotypc, NMV J27564. C. 15 POORE !(>(> liKIAN I . COHEN AND GARY Figure 59, Gnathla mystrium. Holotype, NMV J27564. not visible dorsally. I'leotelson subtriangu- antenna I; flagellum of antenna I of 5 articles, mera lar, lateral straight; with ' aesthetascs; flagellum of antenna 2 of 7 longer than wide; margins articles. Mandible long, two-thirds length of with 2 pairs of simple setae laterally and pair of cephalosome; apex inflexed, distally raised in setae on distal apex. Uropodal peduncle with I lateral view at l >0"; with unarmed carina; slight seta; rami SUbequal, reaching apex of pleotelson; mandibular incisor hair way along; crenulate rami bearing numerous plumose setae distally. blade distally as far as cylindrical apex; sela at Pereopods with few simple setae; pereopod 6 midpoint; erisma pronounced. Maxilliped 5- with 2 anterior spines on merus and crenulate articled; external margins of articles 2-4 bearing anterior margin of basis; pereopod 2 and pereo- plumose setae; eiulite barely reaching article 3, pod 6 with posterior spiniform seta on carpus. narrow. Pylopod 3-articled, internal margin of I'lcopods setose. I'leopod 2 endopod with (> half plumose setae; article 1 with 3 areolae and appendix masculina length of rami. I'enes 2 setae on ventral surface, 4 distally', article 2 with small contiguous papillae. J setae on ventral surface; article 3 minute. I'creon widest anteriorly, as wide as cephalo- Distribution. Bass Strait. 57-130 m depth. some, margins with numerous setae. I'ereonite I dorsally fused with cephalosome, not visible Remarks, Gnathia mystrium is characterised by I'cieomtes 2 and 3 suhequal. I'ereonite 4 with a bifid mediotrontal process and the presence of anterior constriction and 2 anterior lobes, i'er- both superior and inferior lateral processes. The eonite 6 long, at least twice as long as other cephalosome is very large, one-third the length pleomtes. I'ereonite 7 very narrow, overlapping of the whole animal. The mandibles are long and pleon. 1'leon with only 4 segments visible dor- dorsally inflected and pereonite I is indis- sally, other pleonite obscured by pereon; epi- tinguishable. PHYLOGENY AND BIOGEOGRAPHY OF GNATHilDAE 361 Gnathia notostigma sp. now seta; rami subequal, reaching apex of pleotelson, bearing numerous plumose setae distally. Figures 60-62 Pereopods with a moderate cover of simple Material examined. Holotype. Victoria, S of Point setae; pereopod 6 with 2 anterior spiniform setae Hicks (38°14.80'S, 149°9.30'E), 200 m, coarse sand, on mcrus; pereopod 2 with 1 posterior spiniform gravel, WHOI epibenthic sled, M.F. Gomon et al. on seta on carpus; pereopods 2, 5 and 6 with crenu- ORV Franklin, 24 Jul 1986 (stn SLOPE 41), NMV iate anterior margin of basis. J27574 (1 male). Pleopods setose. Pleopod 2 endopod with Paratypc. Type locality, NMV J 19121 (1 male). appendix masculina half length of rami. Penes 2 small contiguous papillae. Description. Total length of holotype: 4.75 mm. Distribution. Eastern Bass Strait, 200 m depth. Cephalosome rectangular, 1.25 times as wide Remarks. Gnathia notostigma is differentiated as long, lateral margins convex. Eyes well devel- from other Australian species by the very pro- oped, lateral and sessile. Frontal border pro- nounced paraocular ornamentation and ridge duced; mediofrontal process broad with bifid most clearly seen in lateral view. G. lignophila projection, 3-4 with setae laterally in inden- Miiller from Malaysia also has similar paraocu- tation between processes; frontolatcral superior lar ornamentation and both species possess a process conical, with 4 setae spread evenly along narrow maxilliped endite. G. notostigma differs external margin. Mediofrontal process paler from G. lignophila in possessing shorter and rest frontal than of border in some specimens, more robust mandibles with a pseudoblade; a ventral appearing to be located to superior fron- conical mediofrontal process with notched lat- tolatcral process but no sutures were found eral margins and only a slight median depression between processes. External scissura rounded. while the mediofrontal process of G. lignophila Supraocular lobe very low, acute. Cephalosome is bifid (large median depression) with smooth with short dorsal sulcus; very pronounced lateral margins; and G. lignophiia unlike G. slight mesolateral paraocular tubercles forming notostigma, is densely covered in granules anter- particularly in ridge, ornamentation noticeable iorly. G. notostigma is also similar to G. cam- lateral view. Antenna 2 longer than antenna 1; ponotus but differs in possessing a more pro- flagellum of antenna 1 of 5 articles, without aes- nounced and anterior paraocular ornamen- thetascs; flagellum of antenna 2 of 7 articles. tation and a mediofrontal process with a slight Mandible straight, two-thirds length of cephalo- median notch. some; with unarmed carina; slight mandibular incisor half-way along; ventral dentate blade on Gnathia odontomachus sp. nov. distal half, with smooth pscudoblade dorsally; internal lobe on proximal half a long crenuiate Figures 63-65 lamina; seta at midpoint; crisma pronounced. Material examined. Holotype. Victoria. Western Port, 5-articled; external margins of Maxilliped on" Crib Point (38°20.94'S, I45°13.33'E), 8 m, fine articles 2-4 bearing plumose setae: endite short, sand mud, Smith-Mclntyrc grab, A.J. Gilmour, Mar- narrow. Pylopod 3-articled, internal margin of ine Studies Group on FV Melita, 29 Mar 1965 (stn simple setae; article 1 with 3 areolae along CPBS-N 21), NMV J4374 (I male). Paratypes. Western Port, Point (38°20.8 1 'S, internal margin, with 1 2 setae distally on ventral offCrib 5° 1 1 1 gravel sand, Smith-Mel (if) re surface and along internal margin, article 2 with 4 3.85'E), 3 m. grab, A.J. Gilmour, Marine Studies Group on FV Melita, 30 6 setae on ventral surface; article 3 minute. Mar 1965 (stn CPBS-N 41 ), NMV J4370 (1 male); 10 Pereon evenly sided, as wide as cephalosome. m, 10 Mar 1965 (stn CPBS-N 23), NMV J4372 (1 1 dorsally small, not reaching lateral Pereonite male). margins and partially obscured laterally by per- length eonite 2. Pereonites 2 and 3 subequal. Pereonite Description. Total of holotype: 2.95 4 with anterior constriction. Pereonites 5 and 6 mm. together longer than rest combined. Pereonite 7 Cephalosome rectangular, 1.33 times as wide very narrow, overlapping pleon. Pleonites 1-4 as long, lateral margins slightly convex. Eyes subequal, 5 narrower; pleonal cpimera promi- well developed, lateral and sessile. Frontal bor- nent. Pleotelson subtriangular, longer than wide; der transverse; mediofrontal process inferior, lateral margins sinuous, slightly notched dis- small, conical; superior frontolatcral process with 3 large setae clumped internal tally; with 2 pairs of simple setae and pair of rounded, on margin and 3 smaller setae setae on distal apex. Uropodal peduncle with 1 evenly spaced on 362 BRIAN F. COHEN AND GARY C. B. POORE Figure 60. Gnathia notostigma. Holotype, NMV .127574. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 363 NMV .127574. Figure 61. Gnathia notostigma. Holotypc, 364 BRIAN F. COHEN AND GARY C. B. POORE Figure 62. Gnatkia notostigma. Holotypc NMV .127574. external margin. External scissura very shallow. on ventral surface and along median margin; Supraocular lobe not pronounced. Cephalosome article 2 with 7 setae on ventral surface; article 3 with small dorsal sulcus and translucent, ellipti- minute. cal region anteromedially, within sulcus and Percon evenly sided, as wide as cephalosome, above buccal cavity. Antenna 2 twice as long as covered with numerous simple setae. Pereonite 1 lateral margins, partially antenna 1; flagcllum of antenna 1 of 5 articles, dorsally reaching with 2 aesthetascs, peduncle length subequal to obscured laterally by pereonite 2; pereonite 4 flagellum; flagcllum of antenna 2 of 7 articles. with a slight anterior constriction and wide Mandible straight, two-thirds length of cephalo- median groove; pereonite 5 with areac laterales. some; proximal third a pronounced basal neck; Pereonite 7 very narrow, overlapping pleon. middle third progressively narrower, ventral Picon ites progressively narrower, pleonal epi- dentate blade; distal third a long, cylindrical mera prominent. Pleotelson subtriangular, as apex; with unarmed carina; mandibular incisor wide as long, with few tuberculcs; lateral mar- half-way along; seta at midpoint near incisor; gins slightly sinuous; with 3 pairs of simple setae erisma pronounced. Maxilliped 5-articled; and pair of setae on distal apex. Uropodal ped- external margins of articles 2-4 bearing plumose uncle with 1 seta; endopod longer than exopod, endite barely reaching article 3, narrow. Pylo- reaching apex of pleotelson; rami bearing pod 3-articled, internal margin of plumose setae; numerous plumose setae distally. article I with ring of short, stouter setae poster- Percopods subequal, with moderate cover of iorly, with 3 areolae distally and 1 2 setae distally simple setae; pcreopod 2 with 1 posterior pecti- PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 365 J4374. Figure 63. Gnathia odontomachus. Holotype, NMV 366 BRIAN F. COHEN AND GARY C. B. POORE Figure 64. Gnathia odontomachus. Holotype, NMV J4374. PHYLOGENY AND BIOGEOGRAPHY OFGNATHHDAE 367 Figure 65. Gnathia odonlomachus. Holotypc, NMV .14374. natc seta on carpus; pcrcopod 6 with 2 anterior Material examined. Holotypc. Victoia, S of Point pectinate setae on merus and crcnulatc anterior Hicks (38°2 1.90'S, 149°20.00'E), 1 000 m, WHO! epi- benthic sled, G.C.B. Poore el al. on ()KV margin of basis. Franklin, 23 Jul 19X6 (stn SLOPE 32), NMV .127577 (I male). Plcopods setose. Pleopod 2 endopod with Paratypes. All collected with WHO! epibenthic sled appendix masculina half length of rami. Penes 2 by G.C.B. Poore et al. on ORV Franklin, Jul 19X6. papillae. small contiguous Tasmania, off Freycinet Peninsula (42"0.20'S, I4X"37.70'E), 720 m, coarse shelly sand Distribution Off Crib Point, Western Port, Vic- (stn SLOPE 46), NMV .1191 I I (I male). 42°2.20'S, I48"38.70'E, toria, 8-1 3 m depth. X00 m, coarse shelly sand, (stn SLOPE 45), NMV Remarks. G. odonlomachus is one of many .119113(1 male). species from around the world which possess a Victoria, S of Point Hicks (38*2 1.90'S, I49°20.00'E), 1000 m (stn SLOPE 32), NMV .127573 inferior, conical medifrontal process and conical (20 males). 38"16.40'S, 149"27.60'E, X00 m, coarse superior processes. Of the Australian fauna it shell (stn SLOPE 34), NMV .1191 12 (2 males). most closely resembles G. latidens (Bcddard) Other material. New South Wales, off Eden disinguished by its hirsute though is easily (37"0.60'S, 150*20. 70'E), 363 m, coarse shell (stn nature; more rounded mediofrontal process; SLOPE 22), NMV .119114(34). and the lack of a pseudoblade. Victoria, S of Point Hicks (3X"2 1.90'S, I49"20.00'E), 1000 in (sin SLOPE 32), NMV .1191 15 Gnathia prolasius sp. nov. (500). Figures 66-68 368 BRIAN F, COHEN AND GARY C. 15. POORE Figure 66. Gnathia prolasius, Holotype, nmv .127577. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 369 Figure 67. Gnathia prolasius. Holotype, NMV J27577. 370 BRIAN F. COHEN AND GARY C. B. POORE Figure 68. Gnalhia prolasius. Holotype, NMV J27577. Description. Total length of holotype: 3.49 basal neck smoothly arced; erisma pronounced, mm. external lateral margin flattened. Maxilliped 5- Cephalosome rectangular, 1 .2 times as wide as articled, palp thin and elongate; external mar- long, lateral margins convex. Eyes well devel- gins of articles 2-4 bearing plumose setae; oped, lateral and sessile. Frontal border pro- internal margin with long setae joined together duced; mediofrontal process quadrate, with 4 into 5 strands; endite short, narrow. Pylopod 3- setae laterally; superior frontolateral process articled, elongate and narrow, internal margin of large, rounded, with anteromedial notch, twice fine short setae; with ring of short, stouter setae length of mediofrontal process, with 2 small posteriorly; article 1 with 6 setae on ventral sur- setae laterally. External scissura smoothly face; article 2 elongate, with 7 setae distally on rounded. Supraocular lobe very low, acute. ventral surface; article 3 minute. Cephalosome with broad dorsal sulcus; paraocu- Pereon evenly sided, as wide as cephalosome. lar granules posterior to eye. Antenna 2 longer Pereonite 1 barely reaching lateral margins dor- ; 1 than antenna 1 flagellum of antenna of 5 sally and partially obscured laterally by pereon- articles, with 1 aesthetasc; flagellum of antenna ite 2. Pereonites 2 and 3 subequal; pereonite 4 2 of 7 articles. Mandible straight, raised distally; rectangular, longer than 2 and 3, with anterior two-thirds length of cephalosome; with unarmed constriction. Pereonite 5 and 6 rounded, as long carina; blade complex, crenulate distally while as others together. Pleonites progressively nar- smooth and linear proximally; seta at midpoint; rower, pleonal epimera prominent. Pleotelson PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 371 subtriangular, longer than wide; lateral margins tral surface, 4 distally; article 2 with 4 setae slightly concave; with pair of simple setae and distally on ventral surface; article 3 minute. pair of setae on distal apex. Uropodal peduncle Pereon widest anteriorly, as wide as cephalo- with 5 small setae: endopod longer than exopod, some. Pereonite 1 weakly fused with cephalo- reaching beyond apex of pleotelson. some, barely reaching lateral margins dorsally Pereopods narrow, with few simple setae; and partially obscured laterally by pereonite 2. ischium to carpus with small lateral projec- Pereonites 2 and 3 subequal; pereonite 4 nar- tions. rower than others, with anterior constriction; Pleopods without setae. Pleopod 2 endopod pereonites 5 and 6 together longer than others lacking appendix masculina. Penes 2 small con- together. Pereonite 6 with small lobuii. Pereon- tiguous papillae. ite 7 very narrow, overlapping pleon. Pleon widest in middle; pleonites 3-5 Distribution. Eastern Bass Strait and south-east- with prominent ern slope, 363-1000 m depth. epimera. Pleotelson subtriangular, longer than wide; lateral margins sinuous; with 1 pair of Remarks. Gnathia prolasius is similar to G stig- simple setae medianly and pair of setae on distal macros in overall body proportions, particularly apex. Uropodal peduncle with 2 setae; rami the pereopods and mouthparts. G. prolasius is subequal. reaching apex of pleotelson; internal easily recognised by the large, semicircular fron- margins of rami bearing numerous plumose tolateral processes. setae. Pereopods subequal, with few long simple setae. Pereopod 6 with 2 anterior pectinate setae Gnathia rhytidoponera sp. nov. on merus; pereopods 2 and 6 with posterior spin- iform seta on carpus. Figures 69-71 Pleopods setose. Pleopod 2 endopod with Material examined. Holotypc. Western Coral Sea. NE appendix masculina subequal length to rami. orTovvnsvillc, Queensland (I7°57'S, 147°02'E). 287- Penes 2 small contiguous papillae. 300 m. epibenthic sledge, M. Piehon et al. on RV Distribution. Western Coral Sea, Cidaris. 16 Jun 1986 (stn 146.2). QM W 1 9962 (1 NE of Towns- male). ville, Queensland, 287-303 m depth. Paratype. Western Coral Sea. NE of Townsvillc. Remarks. Gnathia rhytidoponera is very similar Queensland ( 1 7°22'S, i 46°48'E). 303-296 m. epibent- to G. halei Cals from southern 6'. hic sledge. M. Pichonet al.on RV Cidaris. 1 5 Jun 1986 Queensland. rhytidoponera (sin 143.2). QM W 1 9963 (1 male) differs in possessing a dorsally directed quadrate lobe on the posterior mandi- Description. Total length of holotypc: 3.86 bles and lacking a row mm. of setae each side of the base of the mediofrontal process. Cephalosome subquadrate with a pronounced ventral rostrum, lateral margins convex. Ros- trum narrow, conical with small lateral indenta- Gnathia stigmacros sp. nov. tions. External scissura smoothly rounded. Figures 72-74 Cephalosome with a narrow dorsal sulcus Material examined. Holotypc. Victoria. S of Point extending medianly. all the way to frontal bor- Hicks (38°I4.80'S. 149°9.30'E), 200 m, coarse sand, der. Antenna 2 two times longer than antenna 1; gravel, WHOI epibenthic sled. M.F. Gomon et al. on flagellum of antenna 1 of 5 articles with 3 aes- ORV Franklin. 24 Jul 1986 (stn SLOPE 41), NMV 2 7 articles, thetascs; flagellum of antenna of .127576 (I male). small peduncle articles 3 and 4 with numerous Paratypes. Type locality. NMV .119122 (22 setae. Mandible straight, two-thirds length of males). cephalosome; with unarmed carina; seta at mid- Other material. Tasmania, eastern Bass Strait. 82 point; smooth ventral blade on proximal two- km ENE of North Point. Flinders I. (39°27.7'S. 148°41.4'E). 293 m. coarse thirds, visible in lateral view, with a dentate sand, naturalists' dredge. G.C.B. Poorc on HMAS Kimhla. 28 Mar 1979 pseudoblade dorsally; a quadrate internal lobe (stn BSS 36). NMV J 7793 (8); 70 km ENE of North Point. on proximal dorsal surface of mandible, clearly I. Flinders (39°28.4'S. I48"41.8'E). 1 10 m. coarse sand visible in lateral view. Maxillipcd 5-articled; (stn BSS 35). NMV .17794 (2); 50 km NE of Babel I. articles 2-4 bearing plumose external margins of (39°40.3'S, 148°46.5'E), 293 m. rock, coarse sand (stn setae; endite barely reaching article 3. Pylopod BSS 33). NMV J7795 (11). 3-articIed, internal margin of plumose setae; Victoria, eastern Bass Strait, near Pt Ricardo ven- (37°53'S. 148°30'E), 27-45 m, sand. article 1 with 3 large areolae and 7 setae on medium Smith- 372 BRIAN F. COHEN AND GARY C. B. POORE Figure 69, Gnathia rhytidoponera. Holotypc, QM W 19962 PHYLOGENYANDBKKilXKJRAPHYOFCiNATI IIIDAI 373 Figure 70. (inathia rhytidoponera. Holotypc, QM W 1 9962 374 BRIAN F. COHEN AND GARY C. B. POORE Figure 71. Gnathia rhytidoponera. Holotypc QM w 19962 Mclntyre grab, N. Coleman on FV Sarda, Feb 1991 shaped blade on distal two-thirds, produced (stn MSL-ECi 107). NMV .124631 (2); (stn MSL-EG proximally; seta at midpoint; long, smooth 106). NMV .124630 (1); (sin MSL-EG 103). NMV straight basal neck; erisma pronounced. Maxil- J24628 (2); (sin MSL-EG 104), NMV .124629 (I). liped 5-articled; external margins of articles 2-4 Description. Total length of holotypc: 3.10 bearing plumose setae; palp thin and elongate; mm. endite barely reaching article 3, narrow, with 1 Ccphalosomc rectangular, 1.1 times as wide as coupling hook. Pylopod 3-articled, elongate and long, lateral margins slightly convex. Eyes well narrow, internal margin of fine short setae; with developed, lateral and sessile. Frontal border ring of short, stouter setae posteriorly; article 1 produced, transverse between mandible; medio- with 9 setae on ventral surface, predominantly t'rontal process translucent, with median notch along median axis; article 2 elongate, with 12 and 3-4 long setae laterally; superior frontola- setae on ventral surface; article 3 minute. tcral process conical, with 5-6 short setae on Pereon evenly sided, as wide as cephalosome; lateral margin and 4 larger setae near mandible margins with numerous setae. Pereonitc I barely base. External scissura rounded. Supraocular reaching lateral margins dorsally and partially lobe very low, acute. Cephalosome with broad obscured laterally by pereonitc 2. Pereonites 2 dorsal sulcus; pronounced paraocular tubercles and 3 subequal, pereonitc 4 rectangular, longer and setae. Antenna 2 longer than antenna 1; fla- than 2 and 3; with anterior constriction. Pereon- gellum of antenna 1 of 5 articles, without aesthc- ites 5 and 6 rounded, together as long as others tascs; llagcllum of antenna 2 of 7 articles. Man- combined. Pereonitc 7 not visible. Pleonites 2-4 dible elongate, curved; two-thirds length of subequal; posterior border of plconite 5 pro- ccphalosomc; with unarmed carina; smooth arc- duced; plconal epimera prominent. Pleotelson PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 375 Figure 72. Gnathia stigmacros. Holotype, NMV J27576. 376 BRIAN l\ COIIl'N AND GARY ('. B. POORE Figure 73, Gnathia stigmacros. Holotype, NMV .127576. PHYLOGENY AND BIOGEOGRAPHY OF GNATHUDAE 377 Figure 74. Gnathia xtigmatros. Holotypc, NMV .127576. subtriangular. longer than wide; lateral margins shorter superior frontolateral processes and rela- slightly sinuous; with 2 pairs of simple setae and tively straight frontal border. pair of setae on distal apex. Uropod peduncle without setae; endopod longer than exopod, Monodgnathia gen. nov. reaching beyond apex of pleotelson; rami mar- Type species. Monodgnathia ponera sp. nov. gins with numerous long simple setae. Pereopods narrow, with few simple setae; Diagnosis. Eyes absent. Frontal border pro- ischium to carpus with small lateral projections, duced as distinct delineated region (chalky white particularly on pereopods 5 and 6. in Australian species); without processes. Man- Pleopods setose. Pleopod 2 endopod lacking dible with occluding, smooth mandibular blade. 5- appendix masculina. Penes 2 small contiguous Perconite 1 immersed in cephalon. Pylopod papillae. articled; operculatc, article 2 enlarged; article 3 with spines; lacking plumose setae on external Distribution. Victoria, eastern Bass Strait, 27- margin. Pereopod 4 basis with anterior quadrate depth. 293 m lobe and ischium distally expanded into circular Remarks. Gnathia stigmacros differs from G. cusp. completely smooth prolasius in possessing a Etymology. For Theodore Monod whose monu- setae on the frontal border and blade, many mental 1926 work on Gnathiidac has become a pronounced paraocular tubercles. G, stig- more classic study of a family of Isopoda. macros resembles G. malaysicnsis Miiller in the shape of the mediofrontal process and the man- Remarks. Monodgnathia and Bathygnathia arc- dible but is easily distinguished by its much closely related genera (sec cladogram) with 378 BRIAN F. ( OHFN AND GARY C. B. I'OORF. almost identical pylopods. Both genera possess a junior synonym. Akidognathia poteriophora 5-articled. operculate pylopod with greatly Monod, 1926 is tenatively placed in the new enlarged second article and a minute fifth genus on the basis of the mandible and rostrum article. Monodgnathia is characterised by the although the pylopod is not operculate and the presence of a curved mandible with a smooth basis of pereopod 4 lacks the anterior quadrate mandibular blade, a distinct frontal border lobe. The pylopod, maxilliped and fusion of pcr- which is not produced into a rostrum and the eonites 5 and 6 suggest that A. poteriophora is a absence of a protruding buccal cavity wall. Four subadult specimen with some features not fully species are recognised, two newly described and developed but it must be stressed that this con- two transferred from Akidognathia. Remaining clusion has been reached based on the litera- species of Akidognathia are now members of ture. Bathygnathia of which Akidognathia is now a Key to males of Monodgnathia from Australia 1. Frontal border produced medianly, lacking setae; cephalon lacking projec- tions covering base of mandibles M. ponera — Entire frontal border produced, with setae: cephalon with quadrate projec- tions covering base of mandibles M. colohostntina Monodgnathia colohostruma sp. nov. margins of pereon and partially obscured lat- Figures 75-77 erally by pereonite 2. Pereonite 4 with slight anterior constriction and median groove. Per- Materia! examined. Ilolotype. Victoria, S of Point eonite 5 with dorsal sulcus and areae latcrales. Hicks (38"2I.9'S, I49"20.0'E), 1000 m. WHOI cpi- Pereonite 6 with lobi latcrales and small lobuii. benthic sled, G,C.B. Poore et al. on ORV Franklin, 23 Pereonite 7 small, a thin band; overlapping Jul 1986 (sin SLOPE 32). NMV .1191 15 (I mule). pleon. Pleonites similar, pleonite 5 slightly Description. Total length of holotype: 6.97 longer than others; plconal epimera prominent. mm. Pleotelson subtriangular, as wide as long; lateral Cephalosome rectangular, 1.25 times as long margins slightly sinuous with 5-6 pairs of simple as wide, lateral margins convex. Eyes absent. setae laterally and I medianly. Uropodal ped- Entire frontal border produced, truncated, with uncle with 2 setae; rami of subequal length, 6 large setae medianly and 4-5 smaller setae reaching apex of pleotelson; internal margins of spreading submarginally; distinct chalky white rami bearing few plumose setae. region between mandibles at end of short dorsal Pereopods 2 and 3 less robust than others, sulcus, (cphalosome with low posterior median with dense cover of simple setae; others with tubercle and distinct quadrate cover over base of moderate cover of simple setae; pereopod 4 mandible. Antenna 2 I longer than antenna ; fla- basis with pronounced anterior quadrate lobe, gellum of I of articles, antenna 5 with 3 aesthe- ischium distally expanded as flat, circular pro- lascs; flagellum of antenna 2 of 7 articles. Man- jection with 4 large tubercles; carpus to unguis dible half length of cephalosome; apex curved extending at right angle to basal pereopod, form- inwards; with unarmed carina; smooth occlud- ing a surface with circular cusp of ischium. ing blade proximally and flat dorsal lobe, proxi- Pleopods with short marginal setae. Pleopod 2 mally. Maxilliped 5-articled; external margins of endopod with appendix masculina subequal to articles 2-4 bearing plumose setae; endite length of rami. Penes 2 contiguous papillae. clearly reaching article 3, with 6 coupling hooks. Distribution. Eastern Bass Pylopod 5-articled, with many simple setae Strait slope, 1000 m depth. medianly, mainly on articles 3 and 4; articles 2 and with large 3 areolae; article 3 with 2 pecti- Remarks. Monodgnathia colohostruma and M. nate spiniform setae external on anterolateral ponera are the first records of this genus from margin; article 5 minute. Australian waters. M. COlobstruma and the other Pereon evenly sided, slightly wider than members of this genus differ from the only cephalosome; perconiles progressively longer. known specimen of M. poteriophora (which we Pereonite 1 dorsally small, not reaching lateral believe to be a subadult specimen - see Monodg- PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 379 Figure 75. Monodgnathia colobostruma. Holotype. NMV J 191 15. 380 BRIAN F. COHEN AND GARY C. B. POORE P5 Figure 76. Monodgnathia colobostruma. Holotypc, NMV J 191 15. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 381 Figure 77. Monodgnathia colobostruma. Holotype, NMV J 1 91 15. nathia remarks) in possessing a operculate pylo- Description. Total length of holotype: 1 1 .98 pod and lacking fused pereonites 5 and 6. mm. M. colobostruma possesses a more robust Cephalosome rectangular, 1 .4 times as wide as habitus than other species of Monodgnathia and long, lateral margins convex. Eyes absent. is characterised by a square frontal border pro- Frontal border produced, smoothly rounded as a duced across its entire length, not only between distinct chalky white region, devoid of setae. the base of the mandibles; raised protrusions on External scissura rounded. Supraocular lobe the cephalon at the base of the mandibles and smoothly convex. Cephalon with 2 small slight dorsal lobes on the mandibles. depressions medianly; anterior one larger at base of short sulcus; smaller posterior one near anterior border of peronite I. Antenna 2 longer Monodgtiathia ponera sp. nov. than antenna 1; flagellum of antenna I of 5 Figures 78-80 articles, with 3 aesthetascs; flagellum of antenna 2 of 8 articles. Mandible subequal to length of Material examined. Holotype. Lord Howe Rise, south- cephalosome; apex curved inwards; with western Pacific Ocean (29°13.3'S, 160°35.4'E), 1550 unarmed carina; slight mandibular incisor one- m, epibenthic sled, Australian Musuem party on OR V third way along; small basal neck obscured dor- Franklin, 4 May 1 989 (stn 05/89 site 20), AM P41 294 (I male). sally by rostrum; blades smooth proximally. 182 liKiAN I COHEN AND GARY C. u. POORE I igure 'S \fonodgnathia ponera. Holotype, \M P41294, PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 383 Figure 79. Monodgnathia ponera. Holotype, AM P41294. .1X4 I BRIAN . COHEN AND GARY C. B. POORE iguir 80, Monodgnathia ponera, Holotype, am P41294, PHYLOGENY AND BIOGF.OGRAPHY OF GNATHIIDAE 385 occluding. Maxilliped 5-articled; external mar- Type species. Anceus halidaii Bate and West- gins of 2-4 articles bearing plumose setae, article wood, 1868 (original designation), junior sub- short; endite 2 clearly reaching article 3, narrow, jective synonym of Anceus formica Hesse, with 6 coupling hooks. Pylopod 5-articled, with 1864. many simple setae medianly, from distally on article 2 to base of article 5; article 3 with at least Diagnosis. Eyes present. Frontal margin of 1 pectinate spiniform seta on internal anterola- cephalon produced, without processes. Mandi- teral margin (second seta damaged distally); bles with simple crenulate blade. Pereonite 1 article 5 minute. immersed in cephalon. Pereonite 4 with anterior Pereon widest posteriorly at peronites 5 and 6, constriction. Pylopod 6-articled; operculatc 1.25 times as wide as cephalosome; pereonites (articles I, 3 and 4 enlarged, article 2 reduced); length and width increasing progressively. Pcr- without margin of plumose setae. Pleonites eonite 1 produced slightly, barely reaching lat- without setae. eral margins dorsally and partially obscured Remarks. Paragnathia is a monotypic Afro- laterally by pereonite 2. Pereonite 4 with European genus, the only species being P. for- anterior constriction, median groove as bilobcd mica (Hesse, 1864). The species has a complex sulcus. Pereonite 5 with dorsal sulcus and arcae synonymy (Monod, 1926). It is the only species laterales. Pereonite 6 with small lobi latcrales of Cinathiidae with an operculatc, 6-articled and pronounced lobuii; pereonites 5 and 6 pylopod with a reduced second article and man- longer than other pereonites combined. Pereon- dibles with a crenulate blade. ite 7 very narrow, overlapping pleon. Pleon pro- gressively narrower, epimera prominent. Pleo- tclson subtriangular, longer than wide; lateral Thaitmastogttathia Monod margins slightly sinuous; with 8 pairs of simple Tkaumastognatkia Monod, 1926: 304. setae laterally and pair of small setae on distal apex. Uropodal peduncle I with seta; rami sube- Type species. Thaumastognatliia dieeros qual, reaching beyond apex of pleotelson. bear- Monod, 1926 (monotypy). ing long simple setae. Pereopods with dense cover of simple setae Diagnosis. Eyes present. Frontal border vari- particularly on ischium to dactylus; pereopod 4 able. Mandibles strongly curved with a crenulate dis- basis with anterior quadrate lobe, ischium blade. Antenna 1 with stout peduncle, antenna I tally expanded as Hat. large circular cusp-shaped longer than antenna 2. Pereonite I immersed in projection with 4-5 large tubercles; carpus to cephalon. Mouthparts small, no articles unguis extending at right angle to basis, forming enlarged. Pylopod 4- or 5-articlcd, pediform, not surface with circular cusp of ischium. operculatc Maxilliped highly reduced orabscnt. Pleopods without setae. Pleopod 2 endopod Pereon smooth, cephalosome quasipentagonal, with appendix masculina three-quarters length pereonite 7 not visible dorsally. Pleon often of rami. Penes 2 contiguous papillae. folded under peron. Distribution. South-western Pacific Ocean, 1 550 Remarks. 'Thaumastognatliia is characterised by depth. m the very small size of the pylopod which can be Remarks. M. ponera most resembles M. erista- clearly seen only under a compound micoscope, tipes (Stebbing). Both species possess a smoothly- and the reduction or absence of the maxilliped; rounded frontal border that protrudes between pereon smooth, cephalosome quasipentagonal, the mandibles; relatively simple mandibles; and antennae curved under the mandibles, antennae pronounced lobuii. M. ponera differs from M. I longer than antenna 2, absence of pereonite 7, eristatipes principally in the proportions of the and the pleon folded under the pereon. ccphalon. M. eristatipes possesses a rounded These are the first records of Thaumastogna- cephalon while the cephalon of M. ponera is tliia since Monod (1926) described the type more rectangular. species, T. dieeros, from New Zealand. The three new species bring the total number of species to Paragnathia Omer-Cooper and Omer-Cooper four, all found in Australasia. A specimen belonging to another species of I'haumastogna- Omcr-Coopcr and Omer-Cooper, Paragnathia thia was collected from north Queensland but 1916: 26. — Omer-Cooper 1916: 124. — Monod, was not described because of its poor condition. 1926: 308. All species of Thaumastognatliia are small, Metagnathia Monod. 1922: 645 (type species: less 2.5 long. Anceits formica Hesse, 1864). than mm J86 BRIAN F. COHEN AND GARY C. B. POORE Key to males of species of Thaumastognathia Mandibles wilh pronounced mandibular incisura; plcotelson tapering, mar- gins deeply concave /'. wasmannia Mandibles without mandibular incisura; pleotelson subtriangular, margins straight or slightly sinuous 2 Frontal border slightly excavated, maxillipcds absent T. metaphone Frontal border produced, maxillipcds present 3 Ventral margin of cephalon with pair of strong projections lateral to mandi- bles; carpi of pcreopods with row of even spines T. diceros Ventral margin of cephalon without strong projections; carpi of percopods wilh uneven spination 7*. orectognathus Thaumastognathia metaphone sp. nov. folded under pcreon, pleonitc 5 almost as wide but longer than other pleonites, all without setae. Figures 81, 82 Pleotelson subtriangular, wider than long with Material examined. Holotypc. South Australia. Pear- pair of simple setae laterally and pair of setae on son I„ E side in bay (33'57.30'S, 134*15. ?0'E), 20 m, distal apex. Uropodal peduncle without setae, hryozoans, sponges etc. on shaded surface, SCUBA, endopod twice as long as exopod, not reaching G.C.B. Poore. 17 Apr 1985 (sin SA 55), NMV .127570 apex of pleotelson. with 4 setae distally and I (1 male). seta laterally; exopod with 3 distal setae. Paralype. Type locality, NMV .127560 ( I male). Pereopods with posterior and lateral faces of Description. Total length of holotypc: 2.51 ischi urn-Carpus with irregular acute projections, mm. elsewhere few simple setae. Ccphalosomc quasipcntagonal. 2.3 times as Pleopods without setae. Pleopod 2 endopod wide as long, lateral margins slightly concave. lacking appendix masculina. Penes 2 small con- Eyes well developed, lateral and sessile. Frontal tiguous papillae. border roughly transverse, excavated medianly; mediofrontal process small, rounded, located at Distribution. South Australia, rocky substrate. base of excavation; superior frontolatcral pro- 20 m depth. cess smoothly rounded, forming lateral border for median excavation, with 5-6 setae submar- Remarks, thaumastognathia is characterised by an oval ginally spreading laterally, along slight exca- pereon, cephalosome with concave vationat baseof mandible. Inferior frontolatcral posterolateral margins and a pleon curving process conical, mostly transparent, directly under the pcreon. T. diceros Monod from New ventral to superior frontolatcral process. Zealand is easily distinguishable from T. meta- Supraocular lobe not pronounced. Antennae phone and the other newly described species by the frontal, horn-like protrusions. /'. stout, curved under mandible, antenna 1 longer metaphone is characterised by the slight median than 2; llagellum of antenna 1 of 3 articles, with indentation of the frontal border. 2 aesthetascs; flagcllum of antenna 2 of 3 articles, shorter than last article of peduncle. Mandible strongly curved, depressed in lateral view, half length of ccphalosomc; with unarmed Thaumastognathia orectognathus sp. nov. carina; slight incisura; dentate blade slightly pro- Figures 83, 84 duced on proximal half; seta at midpoint. Maxil- liped absent. Pylopod thin, elongate, 5-articled, Material examined. Holotypc. Victoria, central Bass first and third with seta, fifth minute. Strait,66kmSof'RodondoI.,(39°48.6'S, I46°18.8'E). Hereon oval, wider than ccphalosomc. Per- 82 m, sand-silt-mud, WHOI epibenthic sled, R.S. Wil- son on RV Taitgaroa, 13 Nov 1981 (stn BSS 158). eonite I dorsally small, not reaching lateral mar- NMV .127567 (I male). gins and partially obscured laterally by pereonite Paratypes. Most collected using WHOI epibenthic 2. Peronites 2, 3 and 4 progressively longer. Pcr- sled by R.S. Wilson on RV Tangaroa, Nov 1981. Tas- eonites 5 and 6 fused, longer than others mania. Central Bass Strait, 9 km SSW of Cape Adan- together. Pereonite 7 not visible dorsally. Pleon san. Three Hummock I. (40°30.9'S, I44°56'E), 27 m. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 387 Figure 81. Thaumastognathia metaphone. Holotype, NMV J27570. 388 BRIAN F. COHEN AND GARY C. B. POORE Figure 82. Thaumastognathia metaphone. Holotype, NMV J27570. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 389 Figure 83. Thaumastognathia orectognathus. Holotype, NMV J27567. 390 I5RIAN F. (X)HEN AND GARY C. B. POORE Figure 84. Thaumastognathia orectognathus. Holotype, NMV .127567. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 391 very coarse sand. 2 Nov 1980 (sin BSS 109), NMV with irregular acute projections, propodus .18356 (I). Eastern Bass Strait. 100 km NE of North palms with 2 short spiniform setae. Point, Flinders T„ (38'52.6'S, 148°25.2'E), 1 30 m. fine Plcopods without setae. Pleopod 2 endopod sand, (stn BSS 170). NMV J8361 (I). 85 km NE of lacking appendix masculina. Penes 2 small con- North Point, Flinders 1. (39°02.4'S. I48°30.6'E), 120 tiguous papillae. m. muddy sand (stn BSS 169), NMV J8355 (1). Victoria. Central Bass Strait. 66 km Sof Rodondo I. Distribution. Central and eastern Bass Strait, (39°48.6'S. I46°18.8'E). 82 m, sand-silt-mud (stn BSS 27-200 m depth. 158). NMV .18360(3). Eastern Bass Strait. 43 km SE of Port Albert (38°53.7'S. I47°06.5'E). 58 m. coarse shell Remarks. J'tiamnastognaihia orectognatlnts is (stn BSS 177). NMV J8358(l). NMV J8357(2). 14.3 most easily recognised by its produced frontal km WSW of Pt Ricardo(37°50.74'S. 148°28.40'E). 32 border. m. rock-sand-mud. Smith-Mclntyrcgrab, Marine Sci- ence Laboratories on RV Sarda. 26 Sep 1990 (stn Thautnastognathia wasmannia sp. nov. MSL-EG 46). NMV .124632 (4). Figures 85, 86 Other material. Bass Strait. 15 km S of Gape Wel- lington. (39°03.2'S. 146°39.5'E), 55 m. muddv fine Material examined. Holotype. Tasman Sea, 20 km E sand (sin I 79). BSS NMV .18359 (2): S of Point Hicks of Falmouth, Tasmania (41 °32.9'S, 148°35.0'E), 122 (38'14.80'S. I49°9.30'E). 200 m, coarse sand (stn m. WHOl epibenthic sled, R.S. Wilson on RV Soela, SLOPE 4 1), .119124(2). NMV 10 Oct 1984 (stn S05/84 5), NMV J27579 (1 male). Paratype. Type locality, NMV J27559 (1 male). Description. Total length of holotypc: 1.50 mm. Description. Total length of holotypc: 1.73 Cephalosome quasipentagonal, 1.8 times as mm. wide as long, lateral margins slightly concave. Preserved specimen opaque. Cephalosome Eyes well developed, lateral and sessile. Frontal quasipentagonal, 2.5 times as wide as long, lat- border produced dorsally with slightly excavate eral margins slightly concave. Eyes well devel- truncate midanlerior margin, with 6 setae sub- oped, lateral and sessile. Frontal border trans- marginally each side. Supraocular lobe not pro- verse, produced very slightly at base of mandible nounced. Antennae stout, subequal. curved with shallow excavate midanterior margin, 5 under mandible; flagellum of antenna I of 3 setae submarginally each side forming slight arc. articles, with 4 aesthetascs; flagellum of antenna External scissura very shallow. Supraocular lobe 2 of 4 articles, shorter than last article of ped- not pronounced. Antennae stout, subequal, uncle. Mandible strongly curved, half length of curved under mandible; flagellum of antenna 1 cephalosome; with unarmed carina; without of 2 articles, with 2 aesthetascs; flagellum of incisura; crenulate blade produced on proximal antenna 2 of 4 articles, shorter than last article of half; seta at midpoint. Maxilliped very reduced, peduncle. Mandible strongly curved, two-thirds of 2 articles; first with crenulate mesial margin, length of cephalosome; with unarmed carina; second much shorter, with 4 apical setae. Pylo- pronounced mandibular incisorabout 0.2 length pod thin, elongate, of 4 articles, first with 3 setae, of mandible, thin and very translucent; crenu- third with I seta. late blade weakly produced on proximal two- Pereon oval-rectangular, as wide as cephalo- thirds; setae one-third way along. Maxilliped reaching thin, elongate, of 4 articles, first some. Pereonitc 1 dorsally small, not absent. Pylopod lateral margins and not visible laterally. Pereon- with 2 or 3 setae. Per- ites 2, 3 and 4 progressively longer. Perconites 5 Pereon oval, wider than cephalosome. lateral and 6 fused, longer than others together. Pcreon- eonite 1 dorsally small, not reaching mar- laterally pereonite ite 7 not visible dorsally. Picon folded under gins and partially obscured by pereon, pleonites similar, progressively nar- 2. Pereonite 4 longer than 2 and 3. Peronites 5 longer than others together. rower, all without setae. Pleotelson subtriangu- and 6 weakly fused, setae 7 visible dorsally. Picon folded lar, wider than long, with pair of simple Pereonite not 4 5 as laterally and pair of setae on apex. Uropodal under pereon. pleonites and wide and peduncle without setae, endopod twice as long as longer than anterior ones, all without setae. exopod, reaching beyond apex of pleotelson, Pleotelson elongate, sharply tapering, as wide as dorsolateral^ with 3 setae, distally with 4 setae, long, lateral margins deeply concave with 2 pairs medianly and pair of setae on exopod with 3 distal setae. of simple setae Pereopods 2-6 bases with plumose setae on distal apex. Uropodal peduncle with I seta, rami reaching just beyond apex of pleotel- anterior margins, elsewhere few simple setae, subequal, dorsolateral^' with 3 setae, distally posterior and lateral faces of ischium-carpus son; endopod B. POORE 392 BRIAN F. COHEN AND GARY C. Figure 85. Thaumastognathia wasmannia. Holotypc. NMV J27579. PHYLOGENY AND BIOGEOGRAPHY OF GNATHIIDAE 393 Figure 86. Thaumastognathia wasmannia. Holotype, NMV J27579. with 2 setae; exopod with 3 lateral and 3 distal faces of merus-carpus with irregular acute pro- setae. jections, most pronounced on pereopod 6. Pereopods 4-6 larger than 2 and 3; their bases Pleopods without setae. Pleopod 2 endopod with few plumose setae on anterior margins, lacking appendix masculina. Penes 2 small con- elsewhere few simple setae; posterior and lateral tiguous papillae. 394 BRIAN F. COHEN AND GARY C. B. POORE Distribution. Eastern Tasmania, 122 m depth. Beddard. F.E.. 1886. Preliminary notice of the Iso- poda collected during the voyage of H.M.S. 7. Remarks. wasmannia ischaraeterised by pro- "Challenger." - Part III. Proceedings of the nounced mandibular incisors, relatively straight Zoological Society of London 1886: 97-122. frontal border and deeply concave lateral mar- Birstein. Y.A.. 1963. Deep water isopods (Crustacea. gins on the pleotclson. Isopoda) of the north-western part of the Paclic Ocean. Izadatel'slvo Akademii Nauk SSSR, Mos- Acknowledgments cow [1973 translation Smithsonian Institution and National Science Foundation: Washington. This project is part of a wide-ranging explo- 3l6p. ration of the continental shelf and slope of Boone, PL., 1918. Descriptions often new isopods. south-eastern Australia has been supported and Proceedings of the United Slates National by grants from the Australian Research Grants Museum 54: 591-603. scheme and by the Victorian Institute of Marine Bruce. N.L., 1981. The Cirolanidae (Crustacea: Iso- Sciences. We arc grateful to the ORV Franklin poda) of Australia: new species and a new genus Steering Committee and toCSIRO Marine Lab- from southeastern Australia. Records of the Aus- oratories, Hobart, for the provision of ship-time tralian Museum 33: 644-672. Bruce, N.l.., 1986. Cirolanidae (Crustacea: Isopoda) and to the master and crew of the vessel for help of Australia. Records of the Australian Museum. aboard during the collection of the deep-water Supplement 6: 1-239. material. We are especially grateful to Jean Just Brusca. R.C. and Iverson. E.W., 1985. A guide to the for sorting the material. of the shallow- Much marine isopod Crustacea of Pacific Costa Rica. water material in the collections of the Museum Rcvisia de Biologia Tropical (I'niversidad de of Victoria was obtained with assistance from Costa Rica) 33: 1-77. the Australian Biological Resources Study Brusca, R.C. and Wilson. G.D.F., 1991. A phylogen- which we thank. etic analysis of the Isopoda with some classificat- We thank the following for the loan of ory recommendations. Memoirs of the Queens- 43-204. material: J.K. Lowry, Australian Museum, Syd- land Museum 31:1 Cals, P.. 1972. Gnathiides de l'Atlantique Nord [,- ney, N.L. Bruce, Queensland Museum, Bris- Problcmes lies - l'anatomie et au dimorphisme bane, P. Anderson, National Museum of New sexuel des Gnathiides (Crustacea Isopoda). Zealand, Wellington (for material from the New Description d'unc forme bathyale du Golfe de Zealand Oceanographic Institute) and J.-W. Gascogne: Gnalhia teissen. n. sp. Valuers de Biol- Universitat Wagele, Bielefeld, Germany for the ogic Marine 1 3: 5 I I -540. loan of Antarctic specimens. Cals, P., 1973. Sur une espece nouvelle de Gnalhia d'Australie: Gnalhia halei (Crustaces. Isopodes). References Bulletin Mensuel dc la Societe l.inneenne de Lyon (3) 89: 295-305. A mar, R. and Roman. M.-L. 1 ')74. Invertebres marins - des Xlleme ct XVeme Expeditions Antarctiqucs Cals, P., 1974. Gnathiides de l'Atlantique Nord II. Description de Bathygnaihia monodi sp.. Francises en Torre Adelic. 1 4. Tanaidaees et Iso- a. gna- tluide (Crustacea Isopoda) bathyal Golfe podes. Tethys 5: 56 1 -600. du dc Gascogne. Etude de I'hcterogeneitc metamerique Bacescu, M., I 960. 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