Antennella secundaria ( Gmelin, 1791 )

Mendoza-Becerril, María A., Estrada-González, Mariae C., Mazariegos-Villarreal, Alejandra, Restrepo-Avendaño, Luisa, Villar-Beltrán, Rogelio D., Agüero, José & Cunha, Amanda F., 2020, Taxonomy and diversity of Hydrozoa (Cnidaria, Medusozoa) of La Paz Bay, Gulf of California, Zootaxa 4808 (1), pp. 1-37 : 12-13

Antennella secundaria ( Gmelin, 1791)

Figs. 5 A–E

Sertularia secundaria Gmelin, 1791: 3854 .

Antennella gracilis Allman 1877: 38 , pl. 22, figs. 6–7.— Fraser 1938a: 58.— Fraser 1948: 263.

Type locality. Mediterranean Sea ( Gmelin 1791).

Material examined. Polyp—PB7_37, sampling site (1), mature, 27°C, on alga Sargassum sp.

Description. Colonies from 4 to 8 mm high, monosiphonic, with unbranched hydrocladia arising directly from a creeping hydrorriza. Basal part of hydrocladium with two internodes, the first longer than the second, 57.1–62.8 µm wide, node oblique, with nematothecae. Remainder of hydrocladium divided into alternating thecate and athecate internodes by well-marked oblique nodes and less distinct transverse nodes. Thecate internodes 186.6–536.5 µm long, each with a proximal oblique node and a distal nearly transverse node; one median inferior nematotheca, a pair of lateral pedicellate nematothecae (36.8 µm long), and a median superior axillar nematotheca surrounding hydrotheca. Athecate internodes 307.2–450.3 µm long, each with a proximal nearly transverse node and a distal oblique node, and with two nematothecae. All nematothecae bithalamic and movable, conical; 53.5–71.7 µm long except for smaller axillar nematotheca (30.5 µm long). Gonotheca pear-shaped, 574.3 µm long, 200.9 µm wide, with two-segmented pedicel, arising from the base of hydrotheca; base of gonotheca with two large (75.5 µm long) nematothecae. Exoskeleton with a visible layer corresponding to thin perisarc. Perisarc in thecate internodes (2.8– 3.3 µm wide), athecate internodes (8.6– 2.8 µm wide), nematothecae (1.5 µm wide), gonotheca (2.4 µm wide).

Nematocysts (length x diam.). Microbasic mastigophore (3.7–7.0 x 1.5–3.0 µm).

More detailed description in Calder (1997) and Schuchert (1997).

Taxonomic status. Accepted. AphiaID 117628.

Remarks. Calder (1997: 30) studied the type material of A. gracilis Allman, 1877 and commented on the synonym with A. secundaria ( Gmelin, 1791) . Schuchert (1997) also examined the holotype of A. gracilis and mentioned that it might be of limited value. Allman (1877) and Fraser (1938a, 1948) did not describe the gonotheca. In the Mexican Pacific, only two additional species have been recorded, Antennella compacta Fraser, 1938a , and Antennella avalonia Torrey, 1902 . These are differentiated by the size of the colony, location of thecate segments, nemathothecal arrangement, and gonothecal shape.

Distribution. Species widely distributed in temperate and warm waters of all oceans ( Calder 1997; Schuchert 1997). In Mexican Pacific, the species was reported for Nayarit (Isabel Island and Magdalena Island) ( Fraser 1938a; Fraser 1948, as A. gracilis ), Jalisco (Navidad Head), Colima (Clarion Island), Guerrero (White Friars), and Oaxaca (Tangola-Tangola Bay and Santa Cruz Bay) ( Fraser 1938a, as A. gracilis ).

Figures

FIGURE 5. A–E Antennella secundaria (Gmelin, 1791): A, basal part of hydrocladium; B, internode; C, hydrotheca and nematotheca; D, gonothecae; E, nematocysts microbasic mastigophore. F–K Halopteris violae Calder, Mallinson, Collins & Hickman, 2003: F, monosiphonic colony; G, hydrocaulus and hydrocladia; H, hydrotheca of hydrocaulus; I, nematothecae; J, gonothecae; K, nematocysts microbasic mastigophores. Scale equals A, D, H, J—200 µm; B, C, I—50 µm; E—13 µm; F—3 mm; G—500 µm; K—17 µm.