Saijignium tuamotum, 2005

Achituv, Yair & Langsam, Yaacov, 2005, Coral-inhabiting barnacles (Cirripedia; Thoracica; Balanomorpha; Pyrgomatinae) from east of 150 ° W, Journal of Natural History (J. Nat. Hist.) 39 (20), pp. 1705-1717 : 1713-1716

SaIJignium tuamotum Achituv sp. nov.

( Figure 6 )

Material examined

Holotype: MNHN-Ci 2969 from Goniastrea sp. MNHN-Scle 20271 (field number TUR 6 e; [ T VI, p 1067, 1060]). One specimen; opercular valves. French Polynesia; Tuamotu Archipelago; Tureia Island; 20 ° 50 9 S, 138 ° 33 9 W, 4 November 1965, coll. Chevalier; MUSEUM II (CEA) Expedition.

The specimen of Saυignium tuamotum was found together with Neotreυathana elongatum (MNHN Ci 2967) and Treυathana tureiae (MNHN Ci 2966) on the same piece of Goniastrea .

Diagnosis

Shell fused, oval; scutum transversally elongated, externally concave; adductor ridge distinct; tergum quadrangular, spur absent, inner tooth lacking.

Description

Shell white; fused, flat, oval, rostro-carinal diameter 4 mm. Scutum and tergum white, separate. Scutum transversally elongate, about three times longer than wide; externally concave due to basal margins curved upward forming shallow trough along basal margin; growth ridges prominent, mainly at basal margin, growth ridges along basal margins arching towards occludent margin; oblique, long, narrow furrow from middle of tergal margins to middle of occludent margin. Tergal margins with low wide articulation tooth, growth lines on tooth; adductor ridge prominent, projecting beyond basal margins; adductor pit prominent; adductor ridge and basal margins flaring.

Tergum quadrangular; growth line highly eroded, more distinct at scutal margins; spur absent, articular ridge distinct, furrow with growth lines; internally concave resulting from elevation of articular ridge and carinal margins; crests for depressor muscle absent.

Etymology

The specific name has been derived from the locality where this species was found, Tuamotu Archipelago Island.

Remarks

The genus Saυignium was resurrected by Ross and Newman (1973) to accommodate the pyrgomatine barnacles with a fused, oval shell and a transverslly elongated scutum. Originally, this genus included four species. Anderson (1992, 1993) erected two new genera: Treυathana that contains the Darwin varieties of T. dentata ; and Wanella , which contains W. milleporae Darwin. Anderson (1992) suggested that Saυignium contained two species, S. crenatum with separate opercular plates and S. elongatum with calcified opercular valves. Subsequently, Ross (1999) allocated S. elongatum to a new genus, Neotreυathana. Therefore Saυignium contain only one species, S. crenatum . In Saυignium, the articular ledge of the scutum is wide and occupies the whole tergal margin, the adductor ridge is developed and projects beyond the basal margins. The material from French Polynesia clearly show these characters but the tergum is different from that of S. crenatum , therefore, we deduce that our material is a new species of Saυignium.

Figures

Figure 6. Saυignium tuamotum from Tuamotu Archipelago; Tureia Island. SEM micrographs. (A) Shell outer view; (B) shell inner view; (C) scutum external view; (D) tergum external view; (E) scutum inner view; (F) tergum inner view; (G) scutum oblique out-lateral view seemed from basal margins, showing basal margins and adductor ridge; (H) scutum oblique in-lateral view seemed from basal margins, showing developed adductor ridge. Scale bars: 2 mm (A, B); 1 mm (C–H).