Trevathana noae, Achituv, Yair & Hosie, Andrew M., 2013

Achituv, Yair & Hosie, Andrew M., 2013, Trevathana noae, a new species of coral inhabiting barnacle (Cirripedia: Thoracica: Pyrgomatidae), Zootaxa 3731 (1), pp. 106-112 : 106-110

Trevathana noae sp. nov.

Figs 1–3

Host coral. Favia stelligera (Dana, 1846) .

Material Examined. Holotype: WAM C51680. Paratypes: WAM C51679, C51569; C52750. Other material: WAM C19460. All specimens extracted from same host colony; Cocos/Keeling Islands, North Keeling Island, 11°50’S 96°50’E; Feb 1989; coll. J.C. Veron.

Diagnosis. Trevathana with shell nearly circular, with primary and secondary radial ribs. Scutum transversely elongate, occludent margin 2.3–3.4 times length of tergal margin, with prominent articular tooth. Tergal spur distinct, lacking internal tooth. Cirrus III with diagonal row of 4–9 conical spines on interior surface of 5 distal segments.

Description. Shell pale pink, fused, flat, nearly circular, rostro-carinal diameter 4.0 mm, about 1.25 times that of lateral diameter, number of ribs about 30, primary ribs reaching orifice, secondary and tertiary ribs not reaching orifice ( Fig. 1 A). Shell partly covered with thin layer of host coral skeleton. Sheath covering most of inside of shell, as indicated by concentric growth lines ( Fig. 1 D). Basis cup-shaped, tapering ( Fig 1 B).

Scutum and tergum ( Fig. 1 C) separate, thin, transparent. Scutum transversely elongated, occludent margin 2.3– 3.4 times length of tergal margin, basal margin sinuous; outer surface with growth ridges parallel to basal margin, shallow median furrow nearly parallel to occludent margin. Tergal margin about 45o to occludent margin. Articular tooth rounded, directed towards basal margins, centrally located on tergal margin, width about 0.5 of tergal margin, growth lines on tooth. Adductor and lateral depressor pits shallow, adductor ridge prominent, projecting beyond basal margin.

Tergum ( Fig. 1 C) triangular, growth ridges prominent, obtuse notch on scutal margin. Inner side concave, depression accommodating articular tooth, growth lines inside depression. Spur broad, approximately 0.3 of total tergal height, furrow shallow, growth lines coincident, in small individuals internal surface of spur keeled ( Fig.1 F), in adult specimens internal tooth of tergum lacking.

Labrum bilobed ( Fig. 2 A), lobes oval, 1 tooth on each lobe, V-shaped notch between lobes. Palpus, elongated, club-like, long setae on distal margins.

Mandible ( Fig. 2 D) with 5 teeth along cutting edge, distance between teeth unequal. Upper 3 teeth occupying 0.6 of cutting edge, gap between teeth 1 and 2 less than 0.5 of cutting edge. Teeth 2–4 bifid. Inferior angle with short spines, surface of mandible bearing rows of short, sharp setae.

Maxilla I ( Fig. 2 C) with 9 strong, equal setae on cutting edge, second seta separated from third by slight notch, 2–3 short setae at inferior angle. Simple setae on upper and lower margins. Surface of maxilla with rows of short, sharp setae.

Maxilla II ( Fig. 2 B, E) bilobed, proximal lobe round, larger than elongated distal lobe. Both lobes with setae, setae on distal lobe simple, pinnate on proximal lobe.

Cirrus I ( Fig. 3 A) with rami unequal; anterior ramus antenniform, long, slender, 10-segmented; posterior ramus 0.5 length of anterior ramus, 5-segmented. Apical setae on anterior ramus simple; simple, bipectinate setae on proximal segments of posterior ramus.

Cirrus II ( Fig. 3 F) with anterior and posterior rami subequal, 7- and 6-segmented, respectively; segments of both rami with anterior margins protuberant. Simple setae on apical segment of anterior ramus; simple and few pectinate setae on apical segment of posterior ramus.

Cirrus III ( Fig. 3 C) anterior and posterior rami subequal, 9- and 7-segmented, respectively. Apical segments of anterior ramus with simple setae and few pectinate setae; posterior ramus with pectinate setae on apical segment. Diagonal row of 4–9 conical spines on interior surface of distal 5 segments of posterior ramus.

Cirri IV-VI ( Fig. 3 E) similar; cirrus VI longest, 20-segmented. Five pairs of setae on proximal segments, 2 proximal seta shortest. Three pairs of setae on distal segments. Apical and long setae of each segment pinnate.

Cirral segment counts as follows (left cirri above, right cirri below; *denotes damaged/broken cirri): Penis ( Fig. 3 G) annulated, short seta scattered along length, basidorsal point finger-like.

Etymology. Named in honor of Dr. Noa Simon-Blecher in recognition and appreciation of her contribution to the study of barnacle biology at the Mina Everard Faculty of Life Sciences, Bar Ilan University.

Figures

FIGURE 1. Trevathana noae sp. nov. Hard parts: A. Shell plate (WAM C 51680, holotype). B. Longtitual section of basis showing imbricating shell (WAM C 52750, paratype). C. Inner and outer view of opercular valves (WAM C 51680, holotype). D. Inner view of shell plate (WAM C 52750, paratype). E. Outer view of scutum of a small specimen; note the presence of remnants of the primordial scutum (WAM C 51569, paratype). F. Inner view of scutum and tergum of a small specimen; spur is keeled (WAM C 51569, paratype).

FIGURE 2. Trevathana noae sp. nov. Trophi (WAM C 51680, holotype): A. Labrum and palpus. B. Maxillae II. C. Maxilla I. D. Mandible. E. Maxillae II. Scale bar for A applies to all figures.

FIGURE 3. Trevathana noae sp. nov. Cirri and penis (WAM C 51680, holotype): A. Cirrus I. B. Cirrus II. C. Cirrus III. D. Cirrus V. E. Cirrus III: pectinate setae on apical segment of posterior ramus. F. Cirrus III: conical spines on posterior ramus. G. Basidorsal point of penis. Scale bar of A applies to A, B, C and G.