JOURNAL OF BIOLOGY, 13(4) 769-783, 1993

STYRACOTHORACIDAE (COPEPODA: ), A NEW FAMILY FROM THE PHILIPPINE DEEP SEA

Rony Huys

AB S T R A C T A new family is proposedto accommodateStyracothorax gladiator, new genus,new species, collected from 2,050-m depth in the Philippine Sea. The Styracothoracidaeis placed in the Cervinioidea on account of the fused rostrum, the setation of the antennaryendopod, the reductionof the maxillularyexopod, and the uniramousfifth legs in at least the female. A suite of synapomorphies,including the subchelatemaxilliped, suggestsa sister-grouprelationship with the cave-dwellingRotundiclipeidae. The primitive featuresof the Styracothoracidaeand the phylogeneticrelationships of the cervinioid families are discussed.

The present work arises from a study of tulocarid that is described in a separate ac- the bathyal and mainly abyssal harpacti- count (Huys et al., 1993). coids collected during the second leg of the MATERIALSAND METHODS French ESTASE Expedition in 1984. Co- pepods were collected on board the RV The holotypefemale was dissectedin lactic acid and Jean Charcot during its cruise off the Phil- the dissected partswere placed in lactophenolmount- west coast from Manila to ing medium. Preparationswere sealed with glyceel ippine Surabaya (Gurr?, BDH ChemicalsLtd., Poole, England). in Indonesia. All drawings have been preparedusing a camera The harpacticoid fauna of Phil- lucidaon a Leitz Diaplaninterference microscope. The ippine deep waters has received relatively descriptive terminology is adopted from Huys and little attention, despite the fact that exten- Boxshall (1991). sive surveys have been carried out in the DESCRIPTIONS Philippine Trench during the Danish Gal- new athea Expedition and the various cruises of Styracothoracidae, family the Russian research vessel Vityaz (Belyaev, Diagnosis.--Body slightly depressed, pro- 1972). Virtually all our knowledge of Phil- some distinctly wider than urosome. First ippine deep-sea harpacticoids is contained pedigerous somite fused to cephalosome. in Ito's excellent papers (1982, 1983) on Cephalothorax distinctly deflexed, with I Cerviniidae, Thalestridae, and Ameiridae pair of anterior and 2 pairs of posterior, from an abyssal locality southeast of Min- backwardly directed hornlike projections. danao. The description by Ito of highly dis- Second to fourth pedigerous somites with tinctive harpacticoid taxa such as Tonpos- pairs of dorsal and lateral processes. Pos- tratiotes tenuipedalis, Abyssameira reducta, terior margin of body somites spinular both and Parameiropsis magnus, gives an indi- dorsally and laterally; cuticle profusely or- cation that this area might reveal other un- nate with tubercles, ridges, denticles, and suspected discoveries. The only other deep- spinules, particularly dorsally and dorsolat- water harpacticoid described from the Phil- erally. Rostrum fused to cephalic shield, ippine Sea is Pontostratiotes horrida (Cer- prominent, anteriorly directed. Female gen- viniidae) from 4,300 meters depth in the ital double-somite without internal chitin- northeastern sector near the Bonin Islands ous rib ventrally; original segmentation (Izu-Bonin Trench) (Brotskaya, 1959), but marked by dorsal and lateral ornamentation this locality is quite remote from the Phil- and by lateral constriction. Anal operculum ippine waters proper. vestigial; anal somite concealed beneath This paper reports on the first deep-water spinous posterior rim of penultimate so- harpacticoid to be described from off the mite. Caudal rami short, with 7 setae. Sex- west coast of the Philippines. The single fe- ual dimorphism unknown. male collected represents the type of a new Antennule slender, with large posterior family and was found to be infested by an spinous processes on segment 2 and smaller as yet unknown developmental stage oftan- ones on segments 1-4; 7-segmented in fe- 769

This content downloaded from 193.191.134.1 on Wed, 26 Nov 2014 09:28:32 AM All use subject to JSTOR Terms and Conditions 770 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 13, NO. 4, 1993 male, with aesthetascs on segments 4 and ber-8 December 1984) to the Philippine 7; setae bare (except segment 1). Antenna deep waters on board the RV Jean Charcot with discrete basis and bisetose, uniseg- (organized by the CNRS; coordinators L. mented exopod; endopod with 1 seta on D. Labeyrie and B. Metivier); station CP02 proximal segment and 3 lateral plus 7 apical (14?05.40'N, 120?02.46'E), taken on 14 No- setae on distal segment. Labrum undivided, vember 1984 at a depth of 2,050 m north- with fine spinules. Mandible with biramous west of Manila; collected with dredge-net palp; basis unarmed; endopod 1-segmented and sorted in CENTOB, Brest (coordinator with 2 +7 setae; exopod 2-segmented with M. Segonzac). Dissected on 13 slides and setal formula [4-2]. Paragnaths well devel- deposited in The Natural History Museum, oped, ornamented lobes with broad teeth London, under reg. no. 1992.1066. Maxillule with both rami defined distally. Description of Female (Figs. 1A, 2A-D, 3A- at with 2 with base; exopod setae; endopod F, 4A-E, 5A-C, 6A, B, 7A-D).-Total body 6 basal endites no setae; discrete; epipodite. length 610 ,m from tip of rostrum to pos- with 3 Maxillary syncoxa endites, praecoxal terior margin of caudal rami (measured endite bilobate; endopod indistinctly seg- around dorsal curvature in lateral aspect; with setae. mented, geniculate Maxilliped Fig. 1A). Prosome distinctly wider than uro- with 2 basis syncoxa bearing setae; asetose; some (Fig. 2A). Entire body covered with with 3 small endopod unisegmented spines minute denticles dorsally and laterally (Figs. and 1 claw. long 1A, 2A). Cephalothorax large, measuring P1 with well-developed 3-segmented pro- one-third of total body length; distinctly de- basis with inner topod; extremely long seta; flexed relative to main body axis; with 2 rami not 2-segmented; endopod prehensile. pairs of lateral, backwardly directed, horn- P2-P4 with rami. 3-segmented like processes (Fig. 1A); hind margin with Female fifth of not fused medi- pair legs another pair of similar but longer processes ally but with distinct intercoxal sclerite; uni- dorsolaterally and 2 small protuberances with 5 setae ramous; extremely elongated; middorsally (Fig. 2A); Pi-bearing somite each. incorporated. Epimeral areas of cephalo- Female fused to form trans- gonopores thorax not particularly produced ventrally, slit covered on both sides verse genital by all appendages clearly exposed in lateral as- P6 3 median vestigial bearing setae; copu- pect (Fig. 1A). Rostrum prominent (Figs. seminal bi- latory pore minute; receptacle 1A, 7A), anteriorly directed; fused with dor- lobate. sal cephalic shield; lateral margins spinu- Male unknown. lose; with 2 pairs of sensilla and 1 pair of Marine, free-living. raised pores. First 3 thoracic somites each Type Genus. -Styracothorax, new genus. with 1 pair of dorsolateral and 1 pair of ventrolateral hornlike processes; dorsolat- Styracothorax, new genus eral ones decreasing in length in anteropos- terior with dorsal Diagnosis. -As for family. direction; tergites swelling between dorsolateral processes (Fig. 1A). - new Type Species. Styracothorax gladiator, Posterior and lateral margins of cephalo- species. thorax and prosomites with conspicuous Etymology.-The generic name is derived tricuspidate processes (Figs. 1A, 2A). These from the Greek styrax, genitive styrakos, margins with longer spinous processes in all meaning the spike at the lower end of the urosomites except anal somite (Fig. 7B). P5- shaft of a spear, and thorax, meaning breast- bearing somite with middorsal tuft of long plate or chest, and alludes to the posteriorly setules (Figs. 2A, 7B). Last thoracic and first directed, hornlike projections on the ceph- abdominal somites completely fused and alothorax and free thoracic somites. forming bilaterally constricted genital dou- Gender. -Masculine. ble-somite (Figs. 4A, 7B); original segmen- tation also marked by dorsal and lateral or- Styracothorax gladiator, namentation consisting of spinous processes, new species sensilla, and raised pores. Ventral surface Material Examined. -One female collected of genital double-somite and following so- during ESTASE II expedition (14 Novem- mites largely without surface ornamenta-

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Fig. 1. Styracothorax gladiator, new genus, new species. Habitus, female, lateral view showing attached sexual female stage of Itoitantulus misophricola Huys, Ohtsuka, and Boxshall (Tantulocarida).

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20 u B-D

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Fig. 2. Styracothorax gladiator, new genus, new species. A, habitus, female, dorsal view; B, antenna; C, mandibular gnathobase; D, mandibular palp (pinnate ornamentation of all exopodal and endopodal setae omit- ted).

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Fig. 3.view. Styracothorax gladiator, new genus, new species. A, antennule; B, labrum, anterior view; C, labrum, posterior view; D, right paragnath, anterior view; E, right paragnath, lateral view; F, right paragnath, posterior view.

This content downloaded from 193.191.134.1 on Wed, 26 Nov 2014 09:28:32 AM All use subject to JSTOR Terms and Conditions 774 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 13, NO. 4, 1993 tion except for posterior margin (Fig. 4A). tube seta at distal margin and 2 geniculate Dorsal spinous processesof penultimateso- tube setae arising from anterior surface. mite distinctly bent and covering most of Coxa with 5 setae and 1 geniculate spine; anal somite (Fig. 7B, D). Anal somite small, epipodite absent. Basis (Fig.4E) with 2 en- with spinules around ventral rear margin; dites: proximal endite with 1 geniculateand dorsaloperculum absent. Caudal rami short, 3 simple setae, distal endite with 3 setae. 1.4 times longerthan wide; with 3 largepores Exopod small bisetose segment. Endopod and 7 bare setae (Fig. 7B, D): seta I well defined at base, 1-segmentedwith 6 setae. developed, VII arising from dorsal process Maxilla (Fig. 4B, C) with 3 long endites and tri-articulatedat base. on syncoxa: proximal endite bilobate, de- Antennule 7-segmented(Fig. 3A), with 6 rived from fusion of praecoxalendites, each large spinous processes along the posterior lobe bearing 3 setae; coxal endites with 3 margin of segment 2 and smaller ones on setae each. Basis (Fig. 4B) fused to at least dorsal surface of segments 1-4. Segment 1 proximal segments of incompletely subdi- with long setules along anteriormargin; seg- vided endopod to form allobasis; basal ar- ment 2 longest. All setae bare except for mature consisting of fused claw and 3 dis- segment 1; setal formula:[1, 9, 8, 4+ae, 2, crete setae, endopodal armatureof 6 simple 4, 1+ae]. and 5 geniculate setae. Antenna (Fig. 2B) with coxa not orna- Maxilliped (Fig. 5A) subchelate, slender mented. Basis without setae but with fine and elongate. Syncoxa long, with setular spinules along anterior margin. Exopod rows and 2 pinnate setae. Basis without ar- small, 1-segmented,with 1 short lateraland mature but with spinules along inner and 1 long apical seta. Endopod 2-segmented; outer margins.Endopod 1-segmented,rect- proximal endopod segment with 1 lateral angular;ornamented with very long, curved seta; distal compound segment with 3 setae claw and 3 small spines;claw with proximal laterally and 7 setae (3 geniculate) around half of inner margin serrate. distal margin. PI (Fig. 5B) with well-developed Labrum(Fig. 3B, C) well-developedmus- 3-segmented protopod; precoxa and coxa cular lobe; ventralmargin ornamented with with long spinules; basis with long setules long median setules and short lateral spi- and extremelylong seta at inner margin,and nules; anterior face with 3 pores (Fig. 3B); short seta at outer margin. Exopod posterior face with symmetrical pattern of 2-segmented, outer spines extremely long tiny spinular rows, 2 pairs of tube pores and seta-like;proximal segmentwithout in- laterally, and 1 simple pore medially (Fig. ner seta;distal segmentwith 6 setae in total. 3C). Endopod not prehensile, 2-segmented, Mandible with long gnathobase(Fig. 2C) shorterthan exopod;proximal segment with bearing long teeth along distal margin and 1 inner seta; distal segment with 3 setae. multipinnate seta at dorsal corer. Palp bi- P2-P4 (Figs. 5C, 6A, B) with unorna- ramous(Fig. 2D), with relativelyshort rami; mented intercoxalsclerites. Coxae with set- basis without armature; endopod 1-seg- ules and curved spinous processes at outer mented, setal formula [2 + 7]; exopod 2-seg- margin. Bases transverselyelongated; with mented, compound proximal segment with seta at outer cornerand long setules at inner long setules and 4 lateral setae, distal seg- margin. Proximal segment of exopods with ment with 2 apical setae. All setae of both curvedspinous processes; outer spine ofexp- rami pinnate(ornamentation omitted in Fig. 1 P2 and inner seta of exp-2 P4 strongly 2D). reduced in size. Endopods shorterthan ex- Paragnaths (Fig. 3D-F) well-developed opods; outer distal comer of proximal and chitinized lobes; distal margin with series middle segments with toothlike process. of flattened,overlapping teeth; anterior face Spine and seta formula as follows: concave, with 3 rows of anteriorlydirected spinules; posterior face with tiny spinular area between with exopod segment endopod segment rows; paragnaths long coxa basis 1 2 3 1 2 3 setules posteriorlyand minute denticles an- P1 0-0 1-1 1-0; 2,3,1 0-1; 1,1,1 teriorly. P2 0-0 1-0 I-1; I-1; III,I,3 0-1; 0-2; 1,2,2 Maxillule (Fig. 4D, E) with well-devel- P3 0-0 1-0 I-1; I-1; 111,1,4 0-1; 0-1; 0,2,2 oped praecoxalarthrite with 9 spines and 1 P4 0-0 1-0 1-0; I-1; 111,1,4 0-1; 0-1; 0,2,2

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Fig. 4. Styracothorax gladiator, new genus, new species. A, urosome (excluding PS-bearing somite), ventral view; B, maxilla, endopod and proximal portion of allobasis; C, maxilla (endopod omitted), posterior view; D, maxillule (basis and rami omitted); E, maxillule, basis and rami.

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Fig. 5. Styracothorax gladiator, new genus, new species. A, maxilliped; B, P1, anterior view; C, P2, anterior view.

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A

B

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Fig. 6. Styracothorax gladiator, new genus, new species. A, P3, posterior view; B, P4, anterior view.

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Fig. 7. Styracothorax gladiator, new genus, new species. A, rostrum, dorsal view; B, urosome, lateral view; C, P5-bearing somite and fifth pair of legs, ventral view; D, caudal rami, anal somite, and posterior half of penultimate somite, dorsal view.

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P5 (Fig. 7B, C) uniramous, 1-segmented; setae on the exopod. The setation formula very elongated, about 8 times as long as [4, 2] indicates that the 2-segmented con- wide, slightly bent inward; outer margin dition of this ramus arose as a result of fu- furnishedwith numerouslong setules, 5 bare sion of the three proximal segments. The setae, and 2 raised pores;inner marginwith maxillule shows some modifications in the conical process (bearingpore) at about one- setation plan of the endopod and exopod, third distance from base. Fifth pair of legs but the protopodhas undergonefewer mod- connected by flattened intercoxal sclerite. ifications,as illustratedby the possession of Female gonopores fused to form trans- two discrete endites on the basis, the reten- verse genital slit covered on both sides by tion of the maximum of six setae on the vestigialP6 bearing3 slendersetae (Fig. 4A); coxal endite, and a high numberof armature copulatory pore minute, located in shallow elements on the praecoxalarthrite. Finally, midventral depression;seminal receptacles the spine and seta formula on the distal ex- fused to bilobate reservoirpositioned at lev- opod segment ofthoracopods 2-4 (111,1,3in el of genital slit. leg 2, 111,1,4in legs 3 and 4) is the most Male. -Unknown. primitive recorded among harpacticoids. Speculationsabout the possible relation- -The name is derived Etymology. species ships of S. gladiator are hampered by the from the Latingladiator, meaning "one who lack of information on the male, but the the and alludes to the elab- handles sword," general facies of the body, the mouthparts, of the and orate ornamentation body ap- and the uniramous fifth legs suggest a cer- pendages. tain affinitywith the families of the Cervi- nioidea. Accordingto Huys (1988a) this su- DISCUSSION perfamily currently accommodates the The most conspicuous featureof S. glad- Cerviniidae, , and Rotundicli- iator is perhaps the elaborate ornamenta- peidae. Each of these families has success- tion of the body, in particularthe presence fully exploited its own habitat. The Cervi- of long backwardlydirected, hornlike pro- niidae is an essentially deep-water taxon cesses on the dorsal and lateral sides of the known from bathyaland abyssal sediments, cephalothorax and the thoracic somites. though a few genera are recorded from the Similarstructures are typically found in var- continental shelf (Sars, 1903; Montagna, ious deep-water harpacticoids, such as the 1979). The Rotundiclipeidaeare cavernic- Ancorabolidae (e.g., AncorabolusNorman, olous and thus far known only from a single EchinopsyllusSars, CeratonotusSars, Dor- anchialine cave-dwelling genus in the Ca- siceratusDrzycimski). However, the paired nary Islands (Huys, 1988a) and another as arrangementof these thoracic processes is yet undescribedgenus from Roadside Cave particularly reminiscent of most Cervini- in Bermuda (Huys and Iliffe, in prepara- idae (e.g., Por, 1969; Dinet, 1978). tion). The Aegisthidaeare found exclusively Comparisonof setation patternswith the in the mesopelagic and upper bathypelagic hypothetical ancestralharpacticoid defined zones of the world oceans (Boxshall, 1979). by Huys and Boxshall (1991) shows that S. Huys (1988a) did not formally present a gladiatorretains a suite of primitive features diagnosis of the Cervinioidea, but defined on the mouthpartsand the thoracopods.For the taxon on the basis of four synapomor- example, the ancestralendopodal and basal phies: (i) antennule 8-segmented in the fe- setation of the maxilla (Huys and Boxshall, male, 10-segmentedand with 4 aesthetascs 1991: table 6, fig. 3.10.1) conforming to a in the male, (ii) rostrum fused to cephalo- formula [4, 3, 2, 2, 4] essentially remained thorax,(iii) reducedmaxillulary exopod, and unchangedin S. gladiator.Since the pattern (iv) loss of the P5 endopod. Except for (i), is obscured by incomplete segmental this combination of characterscan be re- boundaries, it is impossible to allocate all gardedas diagnosticfor S. gladiatoras well, armature elements to their respective seg- and to this suite might be added, (v) the ments. However, the full complement of 14 reduction in setation (3 setae) on the lateral setae plus claw is retained. Another plesio- margin of the second antennary endopod morphic characteris exhibited by the man- segment. dible, retainingthe maximum number of 6 For two reasons the antennularycharac-

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780 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 13, NO. 4, 1993

I -V VIII-XIV XV-XVI XVIII- XX XXIXXII XXIVXXV XXVI XXVNI : : : : : : : : : : : :~~~~~~:: : : : : , ANCESTRAL Z: 6 O O - .:: ::...... , ..... , ,1 ]5 I E ' H 7 8 Pontostratiotes ni - L.''''''''''''...... 11 i

Cervinia 1i I I H :I. - ::::::::: ...... Aegisthus aculeatus :-:-: LI I%t;:%','?','?'??.'.'.'.'.'...... ?. .'o'o'-?.'-'-','.'.?.?.?.?.?.?.?.?.?.?%'.'-'-',','?'-'.'?','.'-'-'ii!i!Mii!iiii!:- iii!iiiiiiii!ii-iiiii!iii:-:-:-:-: 'o'o'.' i:-:-:i:-:-:-:-:-:-:: i:-:-:-:-:-:-:-:-:-:-:-:-:---'- DI H

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Fig. 8. Schematic comparison of segmental homologies in the female antennules of representatives of Cervi- nioidea, showing the positions of the aesthetascs derived from ancestral segments XI, XVI and XXVIII (asterisks), and of the posterior seta derived from segment XXIV (diamond). Roman numerals refer to ancestral segments, Arabic numerals denote actual segments. ter defined in (i) can no longer be regarded ed at by Lang (1948) and subsequently cor- as supporting evidence for the monophyly roborated in a cladogram by Huys (1988a). of the Cervinioidea. First, reexamination of Fusion of segments 7 and 8 in the Rotun- the 8-segmented antennules in Cerviniidae diclipeidae is shared with the Styracotho- and Rotundiclipeidae revealed that the re- racidae (Fig. 8). spective segmental fusion patterns are not A second problem relates to the shared homologous. The large aesthetasc derived possession of 4 aesthetascs on the male an- from ancestral segment XVI and found on tennule in Cerviniidae, Rotundiclipeidae, segment 4 in the majority of the harpacti- and Aegisthidae. This distribution pattern coid families, is located on segment 3 in all of sensory elements is unique among the Cerviniidae. This is interpreted as evidence Harpacticoida and was therefore considered that the third segment is a compound seg- apomorphic by Huys (1988a) on the as- ment derived by fusion of the homologues sumption that the supernumerary aesthet- of segments 3 and 4 in the Rotundiclipeidae. ascs were novel structures. Using Calanus Similarly, using the posterior seta of ances- finmarchicus (Gunnerus) as the reference for tral segment XXIV (Huys and Boxshall, comparison, Huys and Boxshall (1991) 1991) as a reference point, shows the sev- charted the distribution of antennulary enth segment in Rotundiclipeidae to be ho- aesthetascs in the different copepod orders mologous to segments 7 and 8 combined, and concluded that despite an overall trend of the Cerviniidae. Maintaining the Rotun- of reduction certain "key segments" are very diclipeidae in the Cervinioidea on the basis conservative throughout the Podoplea. of the other synapomorphies (ii)-(v) means Comparative analysis shows that the cer- that the ancestral condition of the antennule viniid aesthetascs are derived from such an- was 9-segmented and that the 8-segmented cestral key segments, notably VII, XI, XVI antennule has evolved twice through two and XXVIII, and hence their presence is of nonhomologous fusion events. Fusion of limited significance in assessing phyloge- segments 3 and 4 is found in Cerviniidae netic relationships in the Harpacticoida. and Aegisthidae (Fig. 8), further reinforcing The hypothetical phylogenetic relation- their sister-group relationship already hint- ships of the cervinioid families are depicted

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CERVINIOIOEA

Aegisthidae Styracothoracidae Rotundiclipeidae

Cerviniidae

110-15 128-331

15-8 16- 23

Ek Fig. 9. Cladogramdepicting relationshipsbetween the four families of the Cervinioidea.Numerals refer to apomorphiccharacter states given in Table 1. in Fig. 9, using the apomorphic character pacticoida, since it represents the most states compiled in Table 1. Styracothorax common type outside the Cervinioidea. An- gladiator is considered to be the sister group other unusual character is the 2-segmented of the stygobiont Rotundiclipeidae on ac- nonprehensile condition of both rami on leg count of a suite of fusion and reduction pro- 1. This segmentation pattern was thus far cesses in the antennules to the first leg (Table found only in the planktonic Euterpina acu- 1). However, comparison of their respective tifrons (Dana). Comparison with the earliest autapomorphies reveals that Styracothorax copepodid stages known in the Cerviniidae should be placed in a distinct family. The (see Ito, 1983) suggests that this condition establishment of a new family on the base evolved through a heterochronic event, and of a single female might appear premature, that the same mechanism might be applied but is regarded here as the best alternative to explain the segmentation of the mandib- to letting it float around in incertae sedis ular exopod. land. There is no convincing morphological The position of the Cerviniidae is the evidence to satisfactorily assign S. gladiator weakest link in the phylogenetic scheme, to any of the existent families without dra- since it is supported by one autapomorphy matically expanding their respective diag- only. This large disproportion in number of nostic boundaries. evolutionary novelties is a well-known A character of particular interest shared problem in any cladistic analysis where a by the Rotundiclipeidae and Styracothora- primitive taxon shares a sister-group rela- cidae is the subchelate maxilliped. The tionship with an extremely specialized tax- maxilliped of their direct outgroup, the Cer- on such as the Aegisthidae. Failure to detect viniidae, in many respects conforms to the a sufficient number of apomorphies for a ancestral harpacticoid design, though hav- particular clade is often also indicative of ing fewer armature elements than in the Po- its potential paraphyletic status. This raises lyarthra. This might be regarded as evidence the possibility of the Aegisthidae constitut- that the "prehensile" or raptorial type of ing a highly advanced lineage within the maxilliped arose convergently in the Har- Cerviniidae. However, the condition of the

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Table 1. Synapomorphiccharacter states applied to Table 1. Continued. generatecladogram in Fig. 9; plesiomorphicalterna- tives listed in parentheses. 26. Antennule7-segmented in 9, compoundsegments XXIV-XXV and XXVI-XXVIII fused (free). 1. Rostrum fused to dorsal cephalic shield (free). 27. Antennaryexopod 1-segmented(4-segmented). 2. Antennawith 3 setae on lateralmargin of second 28. Antennawith allobasis(basis and firstendopodal endopod segment (5). segment free). 3. Maxillularyexopod reducedto small trisetoselobe 29. Mandible with styletlike gnathobase and unira- (well-developeddiscrete segment with at least 4 mous palp representing elongate basis and setae). 1-segmented endopod (gnathobase unmodified; 4. P5 uniramousin both sexes;exopod and baseoen- palp uniramous). dopod completely fused with no trace of endo- 30. Loss of precoxalendite of maxilla (present). podal lobe left (biramouswith endopod bearing 31. P1 with 1-segmentedrami (2-segmented). armature). 32. Endopodsof P2-P4 2-segmented(3-segmented). 5. Antennule 8-segmented in 9; segments 3 and 4 33. Fifth legs in both sexes reducedto 2 spines arising fused; aesthetasc [XVI] on third segment (9-seg- from somite (exopod and basis forminglarge seg- mented;aesthetasc on segment4). ment). 6. Maxillularyendopod incorporated into basis (free). 7. P6 9 an elongated,rectangular process (small oper- culum). 8. Caudalrami elongated(not elongated). first somite in the 9. of first somite 1 pedigerous Aegisthidae Pleurotergite pedigerous [P ] largely such a demotion The concealedunder dorsal cephalic shield or incom- prevents (character 9). pletely incorporatedinto cephalosome(size equal lack of cladistic evidence in support of the to following pleurotergites). cerviniid branch is interpreted here as mere- 10. Antennule 7-segmentedin 9; segment 5 fused to ly artificial and temporary, since the iden- compound segment [3-4] (free). tification of additional will 11. Antenna with allobasis and 2-segmentedexopod synapomorphies (basis and 4-segmentedexopod). be largely dependent on the discovery of 12. Gross sexual dimorphismin mandible,maxillule, new taxa in the Cervinioidea. The lack of a maxilla and maxilliped(no sexual dimorphism). "missing link" between the Aegisthidae and 13. Mandibular palp vestigial (biramous with the Cerviniidae makes it for cer- and impossible 4-segmentedexopod 1-segmentedendopod). tain characters to be scored For 14. Maxilliped 2-segmented,representing single pro- accurately. topodalsegment and 1-segmented endopod (4-seg- example, the design of the mandibular ex- mented, representing syncoxa, basis and opod in the Cerviniidae (proximal segment 2-segmentedendopod). elongated, distal 3 segments vestigial or in- 15. Caudalrami extremelyelongated, at least twice as is but its long as whole body, with 3 setae (not extremely corporated) unusual, phylogenetic elongated,with 7 well-developedsetae). significance cannot be assessed since the en- 16. Antennule 8-segmented in 9, segment 7 (XXIV) tire palp is rudimentary or entirely lost in fused to segment 8 (XXV) (free). the Aegisthidae (see Huys, 1988b). It is, 17. Loss of armatureon mandibularbasis (armature to whether the of 4 therefore, impossible identify consisting setae). reduction in the was 18. Loss of coxal epipodite on maxillule (epipodite gross Aegisthidae pre- representedby 2 setae). ceded in time by such an exopodal trans- 19. Fusion of praecoxalendites on maxilla(free, wide- formation. Confirmation of the opposite ly separated). event by the discovery of a "missing link" 20. loss Maxillipedsubchelate, endopod 1-segmented, would further strengthen the monophyletic basal endite and extreme reduction of syncoxal endites (maxilliped"stenopodial" not subchelate, status of the Cerviniidae. endopod 2-segmented,basal endite representedby The root cause of the difficulties in delin- 2 setae, syncoxalendites representedby 2, 3, and eating the boundaries in evolutionary terms 2 setae, respectively). of a well-known such as 21. Loss of inner seta on supposedly family proximalexopod segmentof the Cerviniidae be found in our P1 (present). might frag- 22. Fusion (failureto separate)of middle and distal mentary knowledge on biodiversity of deep- exopodal and endopodal segments of P1 (rami sea harpacticoids. For example, the first 3-segmented). representative of the Cerviniidae was de- 23. Genital and first abdominal somites completely scribed as as 1878 G. Stewardson fusedto formgenital double-somite in female(free). early by 24. First pedigeroussomite completely incorporated Brady, but nearly 80% of all species have into cephalosome(discrete). been discovered in the last three decades. 25. Cephalothoraxand thoracicsomites profuselyor- The total number of species stands now at namented with backwardlydirected horny pro- 70. However, Dinet's (1978) report of 12 cesses (no such ornamentation). species of Pontostratiotes occurring in the

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Bay of Biscay only indicates the gross un- tacea, Copepoda).[A survey of the family Cervini- derestimation of this figure. It is clear that idae (Crustacea,Copepoda).]-Zoologicheskij Zhur- the of the ooze is still nal 42: 1785-1803. [In Russian with English exploration abyssal summary.] in its infancy and the total neglect of the Dinet, A. 1978. Le genrePontostratiotes Brady, 1883, hadal community is certainly one expla- dansl'etage abyssal du golfede Gascogne(Copepoda, nation for the extensive gaps in our knowl- Harpacticoida).- Bulletin du Museum National d'Histoire Naturelle, Paris (3)499 (Zoologie 348): edge on copepod evolution. Copepods have 1165-1199. been reportedfrom 9,995-10,002 m in the Huys, R. 1988a. Stygofaunaof the CanaryIslands, KermadecTrench (Belyaev, 1972), yet only 10. Rotundiclipeidaefam. nov. (Copepoda,Harpac- four harpacticoids(Brotskaya, 1963; Beck- ticoida)from an anchialinecave on Tenerife,Canary er, 1974, 1979) were describedfrom depths Islands.-Stygologia 4: 42-63. than the limit of the 1988b. Sexual dimorphism in aegisthid ce- greater 6,000 m, upper phalosomicappendages (Copepoda, Harpacticoida): hadal zone. a reappraisal.-Bijdragen tot de Dierkunde58: 114- 136. ACKNOWLEDGEMENTS , and G. A. Boxshall. 1991. Copepod evolu- tion.-The 159: 1- Grateful thanks are due to Dr. Michel Ray Society, London, England. Segonzac 468. for the ma- (CENTOB,Brest) providing harpacticoid A. and R. Lincoln. The terialcollected the ESTASEII This ,G. Boxshall, J. 1993. during expedition. tantulocaridlife the is contributionno. 600 of the Centrefor Estuarineand cycle: circle closed?-Journal of Crustacean 13: 432-442. Coastal Yerseke (Netherlands Institute for Biology Ecology, It6, T. 1982. Harpacticoid from the Pacific Research).I thankDr. GeoffreyBoxshall for copepods Ecological abyssal off Mindanao. I. Cerviniidae.-Journal of criticallyreading the manuscript. the Faculty of Science, Hokkaido University, Zo- 23: 63-127. LITERATURECITED ology 1983. Harpacticoidcopepods from the Pa- Becker, K.-H. 1974. Eidonomie und Taxonomie cific abyssal off Mindanao. II. Cerviniidae(cont.), abyssalerHarpacticoidea (Crustacea, Copepoda). Teil Thalestridae,and Ameiridae.-Publications of the 1. Cerviniidae-Ameiridae.-Meteor Forschungser- Seto MarineBiological Laboratory 28: 151-254. gebnisse (D)18: 1-28. Lang, K. 1948. Monographieder Harpacticiden.- 1979. Eidonomie und Taxonomie abyssaler HAkanOhlsson, Lund, Sweden. I: 1-896, II: 897- Harpacticoidea(Crustacea, Copepoda). Teil II. Par- 1682. amesochridae,Cylindropsyllidae und Cletodidae.-- Montagna,P.A. 1979. Cervinialangi n. sp. and Pseu- Meteor Forschungsergebnisse(D)31: 1-37. docerviniamagna (Copepoda:Harpacticoida) from Belyaev, G. M. 1972. Hadal bottom fauna of the the BeaufortSea (Alaska,U.S.A.). -Transactions of world ocean.-Israel Programfor Scientific Trans- the AmericanMicroscopical Society 98: 77-88. lations no. 6000107: i-vi, 1-199 (L. A. Zenkevich, Por, F. D. 1969. Deep-sea Cerviniidae(Copepoda: ed.). Originaltitle: G. M. Belyaev, 1966, Donnaya Harpacticoida)from the westernIndian Ocean, col- fauna naibol'shikhglubin (ul'traabissali)Mirovogo lected with R/V Anton Bruunin 1964.-Smithson- okeana. ian Contributionsto Zoology 29: 1-60. Boxshall, G. A. 1979. The planktonic copepods of Sars, G. 0. 1903. Copepoda Harpacticoida.Parts I the northeasternAtlantic Ocean:Harpacticoida, Si- & II, Misophriidae,Longipediidae, Cerviniidae, Ec- phonostomatoidaand Mormonilloida.-Bulletin of tinosomidae(part). -An accountof the Crustaceaof the British Museum (NaturalHistory), Zoology 35: Norway, with short descriptionsand figures of all 201-264. the species.-Bergen Museum, Bergen,Norway. 5: Brady,G. S. 1878. A monographof the freeand semi- 1-28. parasiticCopepoda of the BritishIslands.-The Ray 1: 1-148. RECEIVED:22 October 1992. Society, London, England ACCEPTED:18 1993. Brotskaya, V. A. 1959. Glubokovodnye Harpacti- January coida soovshchenieI. roda Pontostratiotes Reviziya Address: The Natural Brady, 1883. [Deep Sea Harpacticoida.Part I. A Zoology Department, History revisionof the Pontostratiotes Museum, Cromwell Road, London SW7 5BD, En- genus Brady(1883).]- and of K. Zhurnal38: 1785-1789. [In Russian gland, Zoology Institute, University Gent, Zoologicheskij L. Ledeganckstraat35, B-9000 Gent, Belgium. with Englishsummary.] 1963. Obzor semeistva Cerviniidae (Crus-

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