Sessile Organisms 18 (1): 19-26 (2001) The Sessile Organisms Society of Japan
A new coral barnacle, Trevathana paulayi (Cirripedia: Pyrgomatidae), from Guam
Kiyotaka Asami1) and Toshiyuki Yamaguchi2)*
1) Ecosystem Research Center, Ecosystem Conservation Society of Japan, Miyamachi 1-103-1, Omiya, Saitama, Japan, E-mail: [email protected] 2) Marine Biosystems Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan, E-mail:
*corresponding author (TY) E-mail: [email protected]
(Received July 9,2000; Accepted October 2,2000)
Abstract A new species of coral-inhabitingbarnacle, Trevathanapaulayi, is described from Guam, the southernmost of the Mariana Islands. This new species is distinguished from Trevathana dentata (Darwin), formerly called Savignium dentatum, by the color of the wall, the lack of an occludent ledge on the scutum, and the shape of the tergum. The definition of the genus Trevathana is emended to accommodate this new species and also to include Savignium orientale Ren.
Key words: Coral barnacles, Pyrgomatidae, Trevathana, new species, Guam
Introduction but he did not clearly designate type species for Ross and Newman (1973: 159) and Newman and Trevathana and Newmania (=Wanella). Ross (1999) Ross (1976: 57) included four species in Savignium: S. noted that for Trevathana, Pyrgoma dentatum was "type crenatum (Sowerby, 1823: no pagination), S. dentatum by indication", i.e. by monotypy. Anderson (in Ross, (Darwin, 1854:369), S. elongatum (Hiro, 1931: 154), and 1999: footnote) designated Pyrgoma milleporae as the S. milleporum [sic; misspelling of milleporae] (Darwin, type species for Wanella, and therefore both genera pro-
1854: 367). Anderson's (1992) interpretation was that posed by Anderson are valid with his authorship and the Savignium in the foregoing sense is polyphyletic based respective dates of 1992 and 1999. on morphology and cirral activity, and he reclassified the Ren (1986) described Savignium orientale from species into three genera, including two new genera, Nanaodao, Shenzhen, Guangdong, China. This is a rela- Trevathana and Newmania. Savignium (S.S.) was to tively large species, and morphologically it has many accommodate S. crenatum, Trevathana to accommodate distinct features. S. dentatum, and Newmania to accommodate S. This paper describes this new species of Trevathana elongatum and S. milleporum. However, Ross (1999) and emends the definition of Trevathana to accommodate subsequently assigned S. elongatum to a new genus, Savignium orientale Ren and this new species. Neotrevathana, based largely on the morphology of the opercular plates, which are fully calcified together rather Materials examined than separate. Twenty-oneindividuals of Trevathanapaulayi sp. nov. Anderson (1992) was unaware that the name were collected from approximately 2m depth on the coral reef in front of the MarineLaboratory, University of Guam,Pago Newmania was preoccupied, and he later proposed Bay, Guam (13°25′N, 144°46′E) on 13 March 1997. These Wanellaas a replacement name (Anderson, 1993). Ander- specimens were living on the scleractinian coral Acanthastrea son (1992), as noted, divided Savignium into three genera, echinata (Dana). The shell sizes and registration numbers of 20 Sessile Organisms, Vol. 18, no. 1, 2001
the holotype and paratypes are shown in Table 1. The materials with or without occludent ledge; scutum elongate, ad- examined have been deposited in the National Science Museum, ductor plate present or absent, articular ridge projecting Tokyo (NSMT), the National Museum of National History, beyond tergal margin; tergum with short but distinct, or SmithsonianInstitution (USNM), The Natural History Museum, abbreviated, spur and small spur tooth; basis cylindrical, London (NHM), and the Benthic Invertebrates Collection of cup-shaped to deep. Scripps Institution of Oceanography, La Jolla, California (SIO). Type species: Trevathana dentata (Darwin), by monotypy (see Ross, 1999: 833), Recent, Red Sea. This genus ac- On the Genus Trevathana commodates three species, T. dentata, T. orientalis (Ren), Anderson (1992: 330) proposed Trevathana to and T paulayi sp. nov. accommodate one species, Savignium dentatum, and he diagnosed its morphological characteristics as follow: Trevathana paulayi sp. nov. " Wall flat,fused, oval in outline; sheath covering about (Figs 1A-D, 2A-H, 3A-C) one half height of inner wall; scutum elongate, low, Diagnosis.- Wall reddish purple with white ribs, oval. lacking adductor plate; tergum with abbreviated spur and Scutum with short and broad articular ridge and without small spur tooth; basis cylindrical, cup-shaped to deep." occludent ledge. Tergum with abbreviated spur. Description. Wall low and flat, oval, reddish purple, with On Savignium orientale Ren, 1986 approximately 10 white primary ribs and not uncom- Ren (1986) described a new species, Savignium monly a few secondary ribs; bilamellar with thin outer orientale. Anderson (1992, 1993) was unaware of Ren'S lamina, parietal tubes circular, shallow. Shell size shown (1986) paper and this species described in it. Ren (1986) in Table 1. Orifice oval. Sheath more than one half length mentioned that S. orientale closely resembles S dentatum of inner wall; lower margin free. (i.e. Trevathana dentata) in having an adpressed sheath covering about one half the height of the inner wall, a scutum without an adductor plate, and a tergum with an abbreviated spur and small spur tooth. We consider that S orientale should also be assigned to Trevathana (as T orientalis, the spelling being changed to agree with the feminine gender of the genus), and A C therefore propose to emend the definition of Trevathana to accommodate this species.
SYSTEMATICS Subclass CIRRIPEDIA Burmeister, 1834 B D Superorder THORACICA Darwin, 1854 Order SESSILIA Lamarck, 1818 Suborder BALANOMORPHA Pilsbry, 1916 Family PYRGOMATIDAE Gray, 1825 Subfamily PYRGOMATINAE Gray, 1825 E G Tribe PYRGOMATINI Gray, 1825 Genus Trevathana Anderson, 1992 (emended)
H Revised diagnosis of genus F As mentioned above, Trevathana includes Savignium orientale Ren and the new species described here, and is Fig. 1. A-D, Trevathana paulayi sp. nov., holotype: A, right scutum, external view; B, left scutum, internal view; C, emended as follows: right tergum, external view; and D, left tergum, internal Wall single-plated, oval in outline, white or reddish view. E-H, Trevathana dentata collected from the same purple; adpressed sheath, ovoid in outline, covering ap- locality as T paulayi sp. nov.: E, right scutum, external view; F, left scutum, internal view; G, right tergum, external proximately one half height of inner wall; opercular plates view; H, left tergum, internal view. Scale: 1mm. A coral barnacle Trevathana paulayi sp. nov. from Guam 21
Table 1. Sizes (mm) of opercular valves and shell wall of examined specimens of Trevathana paulayi sp. nov.
Opercular valves: Scutum (Fig. 1A, B) more than twice in other species of coral barnacles with single-plated as wide as high; growth lines moderately distinct; shells. occludent margin lacking occludent ledge on apical part; Mouthparts: Mandible (Fig. 3A) with 5 teeth, 2nd-4th articular ridge extremely wide and projecting beyond teeth bicuspid, and with pectinate inferior angle. La- tergal margin; adductor muscle plate absent; lacking dis- brum (Fig. 3B) with 1-5 teeth on each side of deep me- tinct adductor muscle depression; lateral depressor muscle dian notch. First maxilla (Fig. 3C) with straight cutting pit broad and shallow on edge of basal margin. Tergum edge, small notch near anterior corner, large spine on (Fig. 1C, D) quadrangular, lacking external furrow; spur anterior side of notch, and approximately 15 small spines abbreviated with broad, blunt spur tooth internally, lack- on posterior side of notch. ing depressor muscle crests. Penis: Penis longer than cirrus VI, with basidorsal point Base: Cup-shaped, with radial ribs and without longitu- (Fig. 2G, H). dinal tubes. Type locality.- Coral reefs in front of the Marine Labora- Cirri: Numbers of articles in cirri I-VI shown in Table 2. tory, University of Guam, Pago Bay, Guam (13°25′N, Posterior ramus of cirrus I (Fig. 2A) half as long as ante- 144°46′E). Only known from Guam, on the coral rior ramus. Intermediate segments of rami of cirri IV VI Acanthastrea echinata. (Fig. 2D-F) each with 3-4 pairs of setae on anterior mar- Reference material of this new species. C-9436, Benthic gin. Rami not armed with denticles as commonly found Invertebrates Collection, Scripps Institution of Ocean- 22 Sessile Organisms, Vol. 18, no. 1, 2001
Table 2. Numbers of articles on rami of right cirri of Trevathana paulayi sp. nov. (upper) and T. dentata (lower; from Guam); a: anterior ramus, p: posterior ramus. A coral barnacle Trevathana paulayi sp. nov. from Guam 23
R.F. Bolland coll., October 19, 1983.
Remarks.- This new species is allied to but distinguished from T. dentata which has a wide distribution in the west-
C ern Pacific Ocean, by (1) the reddish purple wall with B A white ribs, (2) the lack of an occludent ledge and the wide but poorly projecting articular ridge on the scutum, (3) the almost quadrangular outline of the tergum and more abbreviated tergal spur, and (4) its occurrence on a different host coral species (Table 3). D
E This new species is also allied to T orientalis (Ren), but is distinguished by (1) the lack of an adductor plate, (2) possession of a wide and tall articular ridge, and (3) G the abbreviated tergal spur. In addition, the scutum is thin and fragile in appearance while that of T. orientalis is thick and massive. H
F Etymology.- The species epithet paulayi is in honor of Professor Gustav Paulay, who provided materials for this study. Fig. 2. Trevathana paulayi sp. nov. A-G, holotype: A-F, right cirri I-VI;G penis. H, paratype (19th Paratype), basidorsal Discussion point. Scale: 0.1mm. Trevathana paulayi sp. nov. was compared with T. dentata collected from the type locality of this new spe- cies and Japan. Trevathana dentata was first described as Pyrgoma dentatum by Darwin (1854) based on speci- mens from the Red Sea. Trevathana dentata (Fig. 1E-H) from Guam appears to be identical with variety 1 of P. dentatum of Darwin (1854:pl. 13, fig. 3a-c, g), but in view of the wide geo-
A graphic separation of the two populations, further study may indicate they are distinct species. The morphological differences between T. paulayi sp. nov., T. dentata, and T orientalis are summarized in Table 3. One distinct difference is the relative height of B the articular ridge (Fig. 4; Table 4). The ratios between the height of the articular ridge and the length of the ter- gal margin differ significantly between the two species of Trevathana by greater than the 95% confidence inter- C vals. These ratios and other morphological differences are unmistakable. The host corals also differ between Fig. 3. Trevathana paulayi sp. nov., holotype: A, right mandible; the two species (Table 5). Therefore, the two species are B, labrum; C, right first maxilla. Photographs on left, distinguished both morphologically and ecologically. camera lucida drawings on right. Scale: 0.1mm. Finally, the diagnostic morphological characters of the genera Savignium, Trevathana, and Wanellaare sum- ography. Tweeds Cave Dive area, 0.5km N. of Haputo marized in Table 6.
Point, Guam, 13°34.9′N, 144°49.8′E, 6.1-9.1m depth, 24 Sessile Organisms, Vol. 18, no. 1, 2001
Table 3. Morphological comparison between Trevathana paulayi sp. nov., T. dentata, and T. orientalis.
*: distinct on the specimen Darwin (1854: pl. 13, fig. 3a-g) illustrated.
Table 4. Ratios between lengths of tergal margin and articular ridge of examined specimens of Trevathana paulayi sp. nov, and T. dentata (from Guam). A coral barnacle Trevathana paulayi sp. nov. from Guam 25
Table 5. Host corals of Trevathana paulayi sp. nov. and T. dentata. Data for T. dentata (from Japan) are based on KA'S unpub- lished personal observations.
Table 6. Diagnostic morphological characters of the genera Savignium, Trevathana, and Wanella. Characters of Savignium are based on Ross and Newman (1973) as modified by Anderson (1992).
Acknowledgements We wish to express our sincere gratitude to Dr. Gustav Paulay, Director of the Marine Laboratory, Mr. Teina Longo and Mr. John Starmer, University of Guam, for providing in- teresting specimens and hospitality during our collecting trip. We wish to thank Professor William A. Newman and Dr. Arnold Ross, Scripps Institution of Oceanography, for kindly reading the manuscript, providing invaluable comments, and provid- ing the reference material from the S.I.O. Benthic Invertebrates Collection. We wish to thank Dr. Mark J. Grygier, Lake Biwa Museum, Japan, for kindly providing invaluable comments on our manuscript. This study was supported in part by a Grant- in-Aid for Scientific Research from the Ministry of Education. Science and Culture, project No. 11691172.
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