Oxynaspis perekrestenkoi, 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 : 6-9

Oxynaspis perekrestenkoi sp. nov.

Figures 3 , 4

Material examined. Holotype: CASIZ 110166, 1 complete intact specimen attached to Antipathes cf. A. pennacea ( CASIZ 113583); Fiji Is, Great Astrolabe Reef, S of Herald Passage, outside of reef, under ledge; 18° 46.26’ S, 178° 27.79’ E; depth: 24 m; coll. Robert Van Syoc, 4 June 1998 (RVS-405). Paratypes (all from holotype locality). CASIZ 113628, 1 specimen, shell on SEM stub, mouthparts and cirri on glass microscope slide. CASIZ 110123, 1 specimen. CASIZ 110124, 1 specimen. CASIZ 110140, 1 specimen. CASIZ 110143, 1 specimen. CASIZ 110144, 1 specimen. CASIZ 110152, 1 specimen. CASIZ 110153, 1 specimen. CASIZ 110155, 1 specimen. CASIZ 110156, 1 specimen. CASIZ 110165, 1 specimen. CASIZ 110184, 1 specimen. CASIZ 110185, 1 specimen. CASIZ 110187, 1 specimen. CASIZ 110188, 1 specimen. CASIZ 110190, 1 specimen. CASIZ 110191, 1 specimen. CASIZ 110193, 1 specimen. CASIZ 110194, 1 specimen. CASIZ 110125, 2 specimens. CASIZ 110134, 8 specimens. CASIZ 110141, 6 specimens. CASIZ 110175, 48 specimens. CASIZ 110189, 5 specimens. CASIZ 113622, 50 specimens. SIO-BIC C11214, 2 specimens from CASIZ 110175.

Diagnosis. Small bumps or protuberances on exterior of all plates ( Fig. 3 A–G); carina bent at about 90° angle at umbo ( Fig. 3 C), basal end broadly truncate, not forked or rounded ( Fig. 3 B,C); tergal scutal margin pectinate with small teeth, occludent margin with broad teeth with flattened ends, many of ends touching and fusing with neighboring teeth ( Fig. 3 D,E); scutal tergal margin toothed, basal margin nearly flat to slightly rounded and convex, occludent margin above umbo concave ( Fig. 3 F,G).

Description. Capitulum ( Fig. 4 A,E) with plates approximate except for space between scutum and carina; capitular height greater than twice its width; low growth ridges and small protuberances on all plates, protuberances extending into low radial ridges on scuta ( Fig. 3 A–G); covered with tissue, polyps and spines of host antipatharian and chitinous, golden-brown epicuticle ( Fig. 4 E).

Scutum ( Fig. 3 F,G) somewhat irregularly quadrangular; umbo subcentral, on occludent margin; basi-carinal angle nearly touching carina at basal end; tergal margin toothed and confluent along entire margin; occludent and basal margins forming angle about or greater than 90°; basal margin nearly flat to broadly convex with small notch or indentation close to occludent margin; entire occludent margin coincident with mantle margin; occludent edge with small tooth-like projections; carinal margin nearly straight; adductor muscle pit well-formed, distinct.

Tergum ( Fig. 3 D,E) somewhat triangular with rounded carinoscutal angle and shallowly curved carinal margin leading to apex; margins nearly touching carina and scutum; umbo at apex; scutal margin with tooth-like projections on half closest to occludent edge; occludent edge slightly convex, slightly curving away from occludent margin; occludent margin with small tooth-like projections producing pectinate edge ( Fig. 3 E).

Carina ( Fig. 3 A,B,C) slightly bent in upper portion, line from apex to umbo passing through part of tergum, similarly line from apex to basal/peduncular margin passing through scutum; umbo between lower one-fifth and lower one-third of total height; basal margin broadly truncate, not forked, not extending across peduncle; longer than scutum; extending up about 1/2 length of tergum; width narrowest at umbo and apex; not inflected between basal margin and umbo.

Labrum bullate.

Mandible ( Fig. 4 B) with 5 teeth, first largest, second about one half length of first, third and fourth slightly shorter than second, fifth slightly shorter than fourth; face, superior and inferior margins of mandible setose. First maxilla ( Fig. 4 C) lacking notch; superior part of cutting edge with slight bulge with 1 large and 1 medium spine protruding; cutting edge flat below bulge with many smaller and 2 longer spines; face, superior and inferior margins setose.

Cirrus I ( Fig. 4 D) with anterior ramus shorter than posterior; other cirri with equal, or nearly equal, rami. Setae simple. Cirral counts are as follows:

Caudal appendages absent. Filamentary appendages absent at base of cirrus I. Dorsal filamentary appendages lacking.

Etymology. Named in honor of Michel Perekrestenko, friend and colleague at the California Academy of Sciences, in appreciation for his translations of Russian scientific literature for researchers at our institution, including the works of Memmi and Zevina cited herein.

Remarks. Oxynaspis perekrestenkoi sp. nov. is most similar morphologically to O. joankovenae sp. nov., described below. It differs from O. joankovenae in possessing a tergum with a rounded, rather than flat, basal margin and in having the umbo of the scutum on the occludent margin in O. perekrestenkoi , which is not the case in O. joankovenae . Additionally, the scutum in O. perekrestenkoi has a carinal margin that extends out more toward the carina, such that a line from the carina apex to the carinal basal end passes through the scutum, which is not the case in O. joankovenae .

Figures

FIGURE 3. Oxynaspis perekrestenkoi sp. nov. Paratype, CASIZ 113628. Carina, dorsal view (A), oblique view (B), side view (C). Tergum exterior (D), interior (E). Scutum exterior (F), interior (G). Scale bar equals 1 mm.

FIGURE 4. Oxynaspis perekrestenkoi sp. nov. Paratype CASIZ 110191; 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. 3 for plate details. Paratype CASIZ 113628; Mandible (B), Maxilla 1 (C), Cirrus I (D). Holotype CASIZ 110166; whole specimen, with host tissue and spines covering capitulum (E).