Oxynaspis joandianeae, 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 : 12-15

Oxynaspis joandianeae sp. nov.

Figures 7 , 8

Material examined. Holotype: CASIZ 104150, 1 complete intact specimen, attached to Antipathes sp. ( CASIZ 97824); Pacific Ocean, Caroline Is, Republic of Belau, Ngemelis, steep drop off, Rock Is, 18 m offshore; depth: 15–30 m [Sta. # 22]; 7 August 1974; coll. C. Himmelwright. Paratypes: CASIZ 104151, 5 specimens, attached to Antipathes sp. ( CASIZ 97805); Pacific Ocean, Caroline Is, Republic of Belau, Ngemelis, Rock Is, steep drop off, 91 m offshore; depth: 41 m; 23 July 1974; coll. C. Himmelwright. CASIZ 172661, 1 whole specimen, same locality as CASIZ 104151.SIO-BIC C11212, 2 specimens from CASIZ 104151. CASIZ 104147, 1 specimen, mouthparts and cirri on glass microscope slide, plates on SEM stub, same locality as holotype.

Diagnosis. Bumps or protuberances scattered over exterior of all plates ( Fig. 7 ); carina bent at slightly more than 90° angle at umbo, extending up about one-half length of scutum, basal end flat, not rounded or forked; tergum with occludent margin broadly rounded and slightly inflated at scutal and upper margins to form small protuberances extending slightly beyond margins, spur not truncate; scutum with occludent margin slightly concave above umbo; dorsal filamentary appendage present.

Description. Capitulum with all plates approximate ( Fig. 8 A); capitulum height about twice its width; low growth ridges and small protuberances on all plates; covered with chitinous, golden-brown epicuticle.

Scutum ( Fig. 7 E,F; Fig. 8 A) carinal margin broadly convex, angled, sometimes giving appearance of 2 sides, producing a 5-sided plate; umbo subcentral, near occludent margin; nearly touching carina along entire margin; tergal margin confluent along entire length; occludent and basal margins forming angle of about 90°; basal margin straight or slightly convex; entire occludent margin coincident with mantle margin; occludent margin with small protuberances; adductor muscle pit shallow.

to (E).

Tergum ( Fig. 7 C,D; Fig. 8 A) broadly triangular; margins nearly touching carina and scutum; umbo at apex; scutal margin smooth, shallow concavity on scutal margin (at apex of scutum) near occludent margin; occludent edge slightly convex, slightly curving away from occludent margin; occludent margin with small protuberances.

Carina ( Fig. 7 A,B; Fig. 8 A) curved in upper portion, line from apex to umbo passing outside of carina, similarly line from apex to basal/peduncular margin passing through scutum; umbo in lower one-fifth to one-third; basal margin truncate, not forked, not extending across peduncle; about same length as scutum; width narrowing from basal margin to apex; extending up along about one-half length of tergum; not inflected between basal margin and umbo.

Labrum bullate.

Mandible ( Fig. 8 B) with 3 major teeth along cutting edge, 3 minor teeth at inferior margin of cutting edge, first major tooth longest, second about half length of first, third slightly shorter than second; face of mandible and superior and inferior margins setose.

First maxilla ( Fig. 8 C) with broad, shallow notch on superior half of cutting edge; 2 large spines above notch, several spines along inferior half of notch, many shorter spines below notch; face of maxilla and superior and inferior margins setose.

Cirri I and II ( Fig. 8 D) with anterior ramus shorter than posterior ramus; other cirri with nearly equal or equal number of segments per ramus. Setae simple. Cirral counts are as follows:

CI CII CIII CIV CV CIV Ant. 9 13 13 15 17 15

Post. 11 13 13 15 16 15

Ant. 7 13 14 13 15 16 Post. 10 14 15 16 15 17 Caudal appendages absent. Filamentary appendages absent at base of Cirrus I.

One dorsal filamentary appendage present.

Etymology. Named in honor of Joan Diane Mitchell Dekelboum.

Remarks. Oxynaspis cancellatae Totton, 1940 and O. gracilis Totton, 1940 are the species most similar to O. joandianeae sp. nov., which differs from these two species in the presence of a shallow notch just proximal to the scutal/occludent margin ( Fig.7 C,D). In addition, the carinal umbo position is between the basal one-fifth and basal one-third of the carina in O. joandianae , whereas it is in the basal one-fifth of the carina in O. gracilis and above the basal one-third in the carina of O. cancellatae .

Figures

FIGURE 7. Oxynaspis joandianae sp. nov. Paratype CASIZ 104147. Carina, dorsal view (A), side view (B). Tergum exterior (C), interior (D). Scutum exterior (E), interior (F). Scale bar equals 600 µm.

FIGURE 8. Oxynaspis joandianae sp. nov. Paratype CASIZ 172661; 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. 7 for plate details. Paratype CASIZ 104147; Mandible (B), Maxilla 1 (C), Cirrus I (D). Holotype CASIZ 104150; whole specimen,