Dynamena heterodonta (Jarvis, 1922)

Fig. 1 L–O

Pasythea heterodonta Jarvis, 1922: 344, pl. 24, figs 11–12.

Dynamena heterodonta – Billard 1925b: 198, fig. 44. ― Redier 1966: 86. ― Vervoort & Vasseur 1977: 36, figs 16–17.

Sertularia gracilis – Billard 1905: 334 (not Sertularia gracilis Hassall, 1848: 2223).

non Dynamena quadridentata f. heterodonta – Vannucci 1951a: 83; 1951b: 108, 112, 114 [= D. quadridentata (Ellis & Solander, 1786)].

Material examined

MUSORSTOM 9: Stn. DW1204, small colony composed of four infertile stems, 6–12 cm high, detached from substrate (MNHN-IK-2012-16517); Stn. DW1265, sterile colony with stems up to 2.6 cm high, epizoic on Synthecium sp. (MNHN-IK-2012-16518).

Remarks

The sterile, unbranched stems, divided here and there by oblique nodes, each of which comprises a varied number of isolated hydrothecal pairs, occasionally forming apically stacked groups of two, the lack of evidence of an abcauline caecum in retracted hydranths, the two-cusped hydrothecae with a pleated adcauline flap and a semicircular abcauline flap, and the inconstant presence of internal, submarginal cusps in the hydrothecae suggest that they belong, with little doubt, to Jarvis’ (1922) species.

Vervoort & Vasseur (1977) provided a reexamination of the type material, as well as a discussion regarding its differences with D. quadridentata (Ellis & Solander, 1786) .

Geographical distribution

St. Brandon (Cargados Carajos) (Jarvis 1922), Indonesia (Billard 1925b), New Caledonia (Redier 1966), French Polynesia [Billard (1905), as Sertularia gracilis Hassall, 1848; Vervoort & Vasseur (1977); present study].