Antomma longicarpa (Nutting, 1900)

Galea, Horia R., Di Camillo, Cristina G. & Maggioni, Davide, 2021, An integrative study of Callicarpa gracilis Fewkes, 1881 and Aglaophenia trifida L. Agassiz, 1862, with notes on some hydroids (Cnidaria: Hydrozoa) from French Guiana, Zootaxa 4926 (3), pp. 301-341 : 334-335

Antomma longicarpa (Nutting, 1900)

Fig. A5

Hippurella annulata— Fewkes, 1881: 134, pl. 1 fig. 1, pl. 2 figs 4, 5, 8 (non Hippurella annulata Allman, 1877 ).

Hippurella longicarpa Nutting, 1900: 84 , pl. 17 figs 1–3 [new name for Hippurella annulata sensu Fewkes (1881) ].—Fraser, 1944: 333, pl. 71 fig. 322.—Calder, 2004: 18.

Antomma longicarpa —Stechow, 1919: 852.—Stechow, 1920: 35.—Stechow, 1923: 231.

Description. Colony up to 23 cm high, stem fascicled, bearing on its distal third a series of opposite to alternate side branches that are given off in all directions; condition of the branches not stated; both stem and branches set with alternately-arranged cladia, more distant on stem than on branches; hydrocladia alternate, divided homomerously into long internodes, each with 7–8 intranodal septa, a proximally-set hydrotheca and its complement of 3 nematothecae (one mesial and a pair of laterals), as well as another nematotheca distal on the internode; hydrotheca deep, conical, aperture circular, rim even; distal parts of branches abruptly modified into phylactocarps, composed of stacked verticils of 6 unbranched ramuli; between the bases of adjacent ramuli, there is a nematotheca; a pair of additional nematothecae occurs more distally, where the ramulus, originally given off perpendicularly to the gonosomal axis adopts a vertical posture; finally, a row of nematothecae occur all the way long to their tips; gonothecae quite small, orbicular, arising from the axils of ramuli.

Distribution. Off St. Vincent Island (13°15’ N, 61°12’ W, 227 m), St. Vincent and the Grenadines (Fewkes 1881).

Figures

FIGURE 5. SEM study of Callicarpa gracilis Fewkes, 1881, unbranched morphotype (continued). A. Detail of an empty phylactocarp. B. Portion of a phylactocarp bearing gonothecae. C. Gonothecae, greatly enlarged. D. Three insertions of gonothecae on the proximal, adaxial side of a ramulus. E. Detail of adjacent ramuli. F. Distal end of a phylactocarp seen apically. All from sample MNHN-IK-2015-617. Scale bars: D = 50 µm; E = 100 µm; B, C = 200 µm; A, F = 500 µm.