Oxynaspis joankovenae, Van, Robert J. & Dekelboum, Allen M., 2011

Van, Robert J. & Dekelboum, Allen M., 2011, Oxynaspididae (Crustacea, Cirripedia): phylogenetics and evolutionary ecology, with descriptions of three new genera and six new species, Zootaxa 3103, pp. 1-32 : 9-12

Oxynaspis joankovenae sp. nov.

Figures 5 , 6

Material examined. Holotype: CASIZ 110147, 1 complete intact specimen, attached to Antipathes myriophylla Pallas ( CASIZ 113586); Fiji Is, N Astrolabe Reef, SE side, wall and steep valley channels; 18° 40.54’ S, 178° 31.34’ E; depth: 24 m; coll. Robert Van Syoc, 19 June 1998 (RVS-440). Paratypes (all from holotype locality with exception of CASIZ 110174, as noted below): CASIZ 110128, 1 specimen, shell on SEM stub, mouthparts and cirri on glass microscope slide. CASIZ 110127, 1 specimen. CASIZ 110135, 1 specimen. CASIZ 110146, 1 specimen. CASIZ 110158, 1 specimen. CASIZ 110159, 1 specimen. CASIZ 110126, 5 specimens. CASIZ 110171, 3 specimens. SIO-BIC C11213, 2 specimens from CASIZ 110171. CASIZ 110174, 1 specimen; Fiji Is., Great Astrolabe Reef, N of Herald Passage, coral pinnacles outside of reef; 18° 45.06’ S, 178° 27.99’ E,; depth: 24–27 m,; 6 June 1998; coll. Robert Van Syoc (RVS-410); host specimen CASIZ 110173.

Diagnosis. Small bumps or protuberances on exterior of all plates; carina bent at about 90° angle at umbo, basal end truncate, not forked or rounded; tergum with teeth on all margins, teeth on occludent margin with flattened ends, some meeting and fusing along distal half, tergal spur flattened/truncated; scutum angular with teeth on tergal margin, carinal margin slightly concave and broadly scalloped, basal margin nearly straight with small shallow concavity near occludent margin ( Fig. 5 ).

Description. Capitulum with plates approximate except for large uncalcified space between scutum and carina ( Fig. 6 A); capitular height less than twice its width; low growth ridges and small protuberances on all plates, protuberances extending into pronounced radial ridges and grooves on scuta and terga; covered with chitinous, goldenbrown epicuticle.

Scutum ( Fig. 5 F,G; Fig. 6 A) somewhat quadrangular with various irregularities along margins; umbo subcentral, inset slightly from occludent margin; basi-carinal angle of scutum proximal to and nearly touching basal end of carina; tergal margin toothed and confluent along entire tergum; occludent and basal margins forming an angle about or greater than 90°; basal margin broadly convex with shallow notch or concavity near occludent edge; entire occludent margin coincident with mantle margin; occludent edge with small protuberances, concave above umbo, convex or irregular below umbo; carinal margin broadly concave with two broad projections; adductor muscle pit shallow.

Tergum ( Fig. 5 D,E; Fig. 6 A) broadly triangular; margins nearly touching carina and scutum; umbo at apex; scutal margin with rib-like projections, shallow notch close to occludent edge above scutal apex; occludent edge broadly convex, slightly curving away from occludent margin; occludent margin with small protuberances. Carina ( Fig. 5 A,B,C; Fig. 6 A) slightly curved in upper portion, line from apex to umbo passing outside carina, similarly line from apex to basal/peduncular margin passing through carinal margin of scutum; umbo between lower one-fifth and lower one-third; basal margin truncate, not forked, not extending across peduncle; longer than scutum; width narrowest at umbo and apex; extending up over one-half length of tergum; slightly inflected between basal margin and umbo.

Labrum bullate.

Mandible with 5 or 6 teeth ( Fig. 6 B); if 5-toothed, first largest, second about half length of first, third and fourth slightly shorter than second, fifth half length of fourth; if 6-toothed, first 2 teeth about same size, third slightly shorter, fourth and fifth slightly shorter than third, sixth about half length of fifth; face, superior and inferior margins of mandible setose.

First maxilla ( Fig. 6 C) with notch in superior half of cutting edge, notch about one third length of cutting edge, depth of notch about one seventh length of cutting edge; 2 large spines and 3–5 small spines above notch, many small to medium length spines and 1 large spine below notch; face, superior and inferior margins of maxilla setose. Cirri I and II ( Fig. 6 D) with anterior ramus shorter than posterior ramus. Remaining cirri with near equal number of segments per ramus. Setae simple. Cirral counts are as follows:

CI CII CIII CIV CV CIV Ant. 9 11 13 15 13 14 Post. 10 13 12 13 15 14

Ant. 7 12 15 15 15 14 Post. 7 12 14 15 15 14 Caudal appendages uniarticulate. Filamentary appendages absent at base of Cirrus I. Dorsal filamentary appendages lacking.

Etymology. In honor of Joan Koven for her vital contributions to the establishment of the field station on Dravuni for the study of Astrolabe Reef and for her assistance during the CAS Astrolabe Reef Expedition of 1998. Remarks. Morphologically, the most similar species to O. joankovenae sp. nov. is O. perekrestenkoi sp. nov. The differences between the two species are explained in the Remarks section of O. perekrestenkoi .

Figures

FIGURE 5. Oxynaspis joankovenae sp. nov. Paratype, CASIZ 110128. Carina, dorsal view (A), side view (B), oblique view (C). Tergum exterior (D), interior (E). Scutum exterior (F), interior (G). Scale bar equals 1.5 mm for A; 1 mm for B, D, E, F, G; 750 µm for C.

FIGURE 6. Oxynaspis joankovenae sp. nov. Holotype CASIZ 110147; outline of whole specimen showing general arrangement of plates in relation to each other (A), plate details are not shown in this simple outline drawing, see SEMs in Fig. 5 for plate details. Paratype CASIZ 110128: Mandible (B), Maxilla 1 (C), Cirrus I (D). Holotype CASIZ 110147; whole specimen, with host tissues removed from capitulum, golden-brown chitinous layer visible (E).