Minyaspis amylaneae, 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 : 16-19

Minyaspis amylaneae sp. nov.

Figures 9 , 10

Material examined. Holotype: CASIZ 110160, 1 complete, intact specimen, attached to Cirrhipathes anguina Dana ( CASIZ 113593); Fiji Is, Great Astrolabe Reef, NE of Dravuni I., 18° 44.08’ S, 178° 32.63’ E; depth: 14 m; 18 June 1998; coll. Robert Van Syoc (RVS-439). Paratypes: CASIZ 110132, 1 specimen, mouthparts and cirri on microslide; same locality as holotype. CASIZ 113621, 1 specimen, plates on SEM stub, no body; Fiji Is., N Astrolabe Reef, S end; 18° 40.54’ S, 178° 31.34’ E; depth: 14 m; 20 June 1998; coll. Robert Van Syoc (RVS-444). CASIZ 110132, 1 specimen, mouthparts and cirri on glass microscope slide; same locality as holotype. CASIZ 110133, 1 specimen; same locality as holotype. CASIZ 110167, 1 specimen; same locality as holotype. CASIZ 110136, 1 specimen; Fiji Is, N Astrolabe Reef, SW side, outer reef, sheer wall with shallow caves; 18° 40.17’ S, 178° 31.04’ E; 24–27 m; 13 June 1998; coll. Robert Van Syoc (RVS-426). CASIZ 113617, 1 specimen; Fiji Is, N Astrolabe Reef, SW side, outer reef, sheer wall with shallow caves; 18° 40.17’ S, 178° 31.04’ E; 24–27 m; 13 June 1998; coll. Robert Van Syoc (RVS-426). CASIZ 113618, 1 specimen; Fiji Is, N Astrolabe Reef, SW side, outer reef, sheer wall with shallow caves; 18° 40.17’ S, 178° 31.04’ E; 24–27 m; 13 June 1998; coll. Robert Van Syoc (RVS-426). CASIZ 113615, 3 specimens; Fiji Is, N Astrolabe Reef, SW side, outer reef, sheer wall with shallow caves; 18° 40.17’ S, 178° 31.04’ E; 24–27 m; 13 June 1998; coll. Robert Van Syoc (RVS-426);. CASIZ 113616, 2 specimen; Fiji Is, N Astrolabe Reef, SW side, outer reef, sheer wall with shallow caves; 18° 40.17’ S, 178° 31.04’ E; 24–27 m; 13 June 1998; coll. Robert Van Syoc (RVS-426). CASIZ 113619, 2 specimens; Fiji Is, Great Astrolabe Reef, SE corner of outer reef; 18° 41.47’ S, 178° 31.24’ E; depth: 21 m; 22 June 1998; coll. Robert Van Syoc (RVS-448). CASIZ 113620, 21 specimens, Fiji Is, N Astrolabe Reef, S end; 18° 40.54’ S, 178° 31.34’ E; depth: 14 m; 20 June 1998; coll. Robert Van Syoc (RVS-444); SIO-BIC C11215, from CASIZ 113620.

Diagnosis. Single filamentary appendages on either side at base of cirrus I; caudal appendages absent; tergum and scutum without toothed or jagged margins; carina forming angle greater than 90° at umbo, basal end with shallow fork ( Fig. 9 ).

Description. Capitulum with large non-calcified area between scutum and carina ( Fig. 10 A); capitular height less than twice its width; low growth ridges on all plates; scuta and terga with opaque white markings approximate to adductor muscle attachment sites; covered with chitinous, golden-brown epicuticle.

Scutum ( Fig. 9 E,F; Fig. 10 A) irregularly shaped, not quadrangular; umbo subcentral, not on occludent margin; separated from carina by wide non-calcified area except near basal margin of carina; near tergum at slightly less than one-half length of tergum; occludent and basal margins forming an angle less than 90°; basal margin with well-defined concavity; occludent margin coincident with mantle margin; occludent edge smooth, broadly concave in upper half; carinal margin shallowly concave; adductor muscle pit shallow.

Tergum ( Fig. 9 C,D; Fig. 10 A) broadly triangular; margins nearly touching carina and scutum; umbo below apex; scutal margin smooth; occludent edge broadly convex.

Carina ( Fig. 9 A,B; Fig. 10 A) straight in upper portion, line from apex to umbo passing only through carina, similarly line from apex to basal/peduncular margin passing through scutum; umbo between basal one-fifth and one-third; basal margin deeply forked, extending less than halfway across peduncle; longer than scutum; width narrowest at umbo; extending up about one-half length of tergum; lacking shallow inflection between basal margin and umbo.

Labrum bullate.

Mandible ( Fig. 10 B) with 4 teeth and rounded fifth subtooth at cutting edge inferior margin, first tooth largest, second about half length of first, third and fourth slightly shorter; face of mandible and superior and inferior margins setose.

First maxilla ( Fig. 10 C) with deep notch in superior half of cutting edge; 2 large, long spines above notch, many slightly shorter spines below notch; setae in notch, on face of maxilla and along superior and inferior margins.

Cirrus I ( Fig. 10 D) with anterior ramus shorter than posterior; other cirri with rami about equal. Setae simple. Cirral counts are as follows:

CI CII CIII CIV CV CIV Ant. 6 12 16 14 16 17 Post. 10 12 16 14 15 17

Ant. 7 16 17 17 17 15 Post. 14 17 17 15 16 16 Caudal appendages absent. Single filamentary appendages absent at base of Cirrus I. Dorsal filamentary appendages lacking.

Etymology. Named in honor of Amy Lane Palenscar Van Syoc, who assisted in collecting specimens on the CAS Dravuni Astrolabe Reef Expedition of June 1998.

Remarks. Although they are somewhat similar in outward appearance, the terga of M. reducens ( Foster, 1982) have prominently toothed edges while those of M. amylaneae sp. nov. have smooth edges. Minyaspis amylaneae falls between the M. granti ( Totton, 1940 / M. bocki ( Nilsson-Cantell, 1921) and the M. michi ( Zevina, 1983 / M. sinensis ( Ren, 1983) branches in the phylogenetic tree herein based on morphological characters ( Fig. 15 ). It can be distinguished from these closest species by the proximity of the basal margins of the scutum and carina in M. amylaneae . These two plates are not close to each other in any of the other four species. Minyaspis amylaneae also has the carinal umbo above the basal one-fifth and below the basal one-third of the carina, whereas in M. granti and M. bocki the umbo is located in the basal one-fifth of the carina and in M. michi and M. sinensis it is located above the basal one-third of the plate.

Figures

FIGURE 9. Minyaspis amylaneae sp. nov. Paratype, CASIZ 113621. Carina, dorsal view (A), side view (B). Tergum exterior (C), interior (D). Scutum exterior (E), interior (F). Scale bar equals 1.5 mm for A, B, C, D; 1 mm for E and F.

FIGURE 10. Minyaspis amylaneae sp. nov. Paratype CASIZ 110136; 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. 9 for plate details. Paratype CASIZ 110132; Mandible (B), Maxilla 1 (C), Cirrus I (D). Holotype CASIZ 110160; whole specimen, with host tissues covering capitulum except where abraded away from handling (E).

FIGURE 15. Phylogenetic consensus of 18 shortest trees (147 steps each) using morphological characters for known taxa of Oxynaspididae and two outgroup species, Lepas anatifera and Dosima fascicularis.