Sertularella fraseri

Galea, Horia R., 2010, Additional shallow-water thecate hydroids (Cnidaria: Hydrozoa) from Guadeloupe and Les Saintes, French Lesser Antilles, Zootaxa 2570, pp. 1-40 : 18

Sertularella fraseri nom. nov.

(fig. 5A–G)

Sertularella ornata Fraser, 1937: 2 , pl. 1 fig. 3.

not Sertularella ornata ― Medel Soteras et al., 1991: 526, fig. 10 [= Sertularella fusiformis ( Hincks, 1861) f. ornata Broch, 1933: 74 , fig. 30].

Material examined. Stn.11: 30.11.2009, 15–18 m—a colony with both stolonal and erect growth forms, and three empty gonothecae, on sponge (part as MHNG-INVE-68723).

Description. Colony composed of both stolonal and erect growth forms, arising from creeping, linear, rarely branched stolon. Stolonal hydrothecae rare, representing incipient erect stems. Erect form monosiphonic, generally unbranched, to 10 mm high, composed of a basal part (170–690 µm long) devoid of hydrothecae, and much longer, distal part, divided into slightly geniculate internodes. Internodes, as much as 17 per erect stem, of variable length (425–850 µm), delimited by slightly marked, oblique nodes (diameter 80–105 µm), alternating in opposite directions. Proximal end of internode with bulge on side opposite to hydrotheca carried by preceding node (fig. 5C); distally bearing a hydrotheca. A single lateral branch occurs on one stem; it arises from below a stem hydrotheca; first internode longer than next ones; structure similar to that of stem. Hydrotheca fusiform, adnate for less than half adcauline length (190–220 µm long); free adcauline side 250–280 µm long; abcauline side 375–415 µm long; base 95–105 µm wide. Wall provided with 5–6 rings completely encircling hydrotheca; a smooth neck region (70–90 µm long, 125–145 µm wide) distally; aperture 160–170 µm wide, pentagonal in apical view (fig. 5D), with two latero-adcauline, one abcauline, and two latero-abcauline sides; aperture with four sharp, pointed cusps separated by quite deep embayments; four opercular flaps. Five internal projections of perisarc below the rim, one on each side of aperture. The abcauline cusp may be hypertrophied (fig. 5D, right), and the latero-abcauline ones only slightly marked (fig. 5D, left). Three spent gonothecae present; all arise from middle part of basal stem internodes; 830–890 µm long, 535–605 µm wide in middle; wall provided with 9–11 transverse ribs; neck region ca. 150 µm wide, 60–70 µm high; aperture with four small, rounded perisarc projections. Gonotheca slightly flattened dorso-ventrally (fig. 5G).

Remarks. The specific name of Fraser’s (1937) species is threatened by Sertularella fusiformis ( Hincks, 1861) f. ornata Broch, 1933 . The latter was obviously intended as a subspecific name and, according to the Art. 46.1 of the ICZN, it is deemed to have been simultaneously established at both subspecific and specific ranks. Sertularella ornata Fraser (1937) therefore becomes a junior synonym of Broch’s (1933) variety. I introduce the new name Sertularella fraseri for the former.

Caribbean records. Puerto Rico ( Fraser 1937).

World distribution. Known only from the Caribbean.