Trevathana synthesysae Achituv

Achituv, Yair & Langzam, Yaakov, 2009, Two new species of Trevathana (Crustacea, Cirripedia, Balanomorpha, Pyrgomatidae) from the Western Indian Ocean and French Polynesia, Zootaxa 2116, pp. 46-52 : 46-47

Trevathana synthesysae Achituv sp. nov.

Figures 1 , 2

Host coral Plesiastrea versipora

Material examined: Barnacle extracted from colonies of Plesiastrea versipora collected by Gérard Faure at Réunion Island and Mauritius, housed at the Muséum national d’Histoire naturelle, Paris, ( MNHN) and in the coral collection of ECOMAR, University of Réunion. Holotype and paratypes deposited in the Muséum national d' Histoire Naturelle, Paris.

Holotype: MNHN-Ci3025 from MNHN-scle20404 (REU 882) Réunion Island, Faure Collection.

Paratypes: MNHN-Ci3026 from MNHN-scle20404 (REU 882), Réunion Island, Faure Collection; MNHN-Ci3027 from REU 431, Réunion Island, ECOMAR coral collection, University of Réunion; MNHN- Ci3028 from MAU 256, Mauritius, ECOMAR coral collection, University of Réunion.

Diagnosis. Trevathana with purple rounded shell, about 30 low radial ribs with up to seven projections per rib. Width of scutum about half its length, tergal tooth broad, adductor ridge prominent, projecting over basal margin. Tergum nearly quadrangular, spur short, broad, internal tooth of tergum broad, perpendicular to basal margin.

Description. Shell purple-red ( Fig. 1 ) fused, nearly round, slightly concave, elevated at carinal end, maximum rostro-carinal diameter 7 mm. In mature specimens, rostro-carinal diameter to lateral diameter ratio 1.5:1 ( Fig. 2 A), in smaller specimens, ratio 2:1 ( Fig. 2 G, H). Radiating ribs carrying rows of small projections on surface of shell, up to seven projections per row, maximum number of primary and secondary ribs 30. Shell tubiferous, number of radiating tubes equal to number of ribs. Inner side of shell highly concave, sheath, purple, covering about half inner side of shell, concentric growth ridges on sheath.

Orifice elliptical, located in middle of shell, rostro-carinal diameter about one third of rostro-carinal diameter of shell ( Fig. 2 A), length about twice width. Basis white, tapering.

Scutum and tergum white, separated.

Scutum ( Fig. 2 C, E) transversally elongated, outer surface with growth ridges, median closed furrow nearly parallel to occludent margin. Occludent margin twice as long as tergal margin. Tergal margin about 45o to occuludent margin. Angle between tergal and basal margin obtuse. Tooth projecting at tergal margin, located closer to occuludent margin than basal margin, width about half length of tergal margin. Adductor pit deep; lateral depressor shallow, hardly distinct. Adductor ridge very prominent, projecting beyond basal margin.

Tergum ( Fig. 2 D, F) quadrangular, with growth ridges on outer surface, rounded spur distinct, shallow furrow on surface of spur. Shallow, longitudinal furrow extending from middle of scutal margin to carinobasal angle. Inner surface with depression accommodating tergal tooth on scutal margin; growth lines inside depression, small notch in middle of depression. Thin, elongated, inward projecting tooth on spur, long axis of tooth parallel to long axis of spur.

In young specimens ( Fig. 2 G, H), shell conic, orifice at apex of cone, shell more elongated along carinorostral axis than in mature specimens, projections on ribs restricted to perimeter of shell, number of projections increasing with the size.

Etymology: The specific name designates the SYNTHESYS Project of the European Union, which supported the visit to the Muséum national d’Histoire naturelle, Paris.

Figures

FIGURE 1. Trevathana synthesysae, attached to Plesiastrea versipora from Réunion Island.

FIGURE 2. SEM micrographs of Trevathana synthesysae attached to Plesiastrea versipora from Réunion. (A) Shell outer view; (B) shell inner view; (C) scutum inner view; (D) tergum inner view; (E) scutum outer view; (F) tergum outer view; (G) juvenile specimen outer view; (H) juvenile specimen inner view.