Cladocarpus bathyzonatus Ritchie, 1911

Watson, Jeanette E., 2018, Some Hydroids (Cnidaria, Hydrozoa) from the Great Australian Bight in the collection of the South Australian Museum, Zootaxa 4410 (1), pp. 1-34 : 20-22

Cladocarpus bathyzonatus Ritchie, 1911

Figure 8G–I

Cladocarpus ? bathyzonatus Ritchie, 1911: 861 , pl. 89, figs 2, 6–11.

Cladocarpus bathyzonatus .— Bedot, 1921: 326.— Vervoort, 1966: 153, fig. 53.— Bouillon et al, 2006: 283. Cladocarpella multiseptata Bale, 1915: 304 , pl. 47, figs 1–5.— Stranks, 1993: 12.

Material examined. SAM H2324, preserved material; one microslide ( SAM H2592). Near South Australia – Western Australia border, depth 180 m, trawl; coll: R. Southcott 1/07/1988 .

Description. One small infertile stem 60 mm long. Hydrorhiza a loose straggling stolon, stem polysiphonic, one supplementary tube running almost to distal end of stem. Distal 8 mm of stem hydrocladiate, apophyses on lower stem indicating lost hydrocladia. Hydrocladial internodes long, narrow, strongly septate with eight complete vertical septa.

Hydrotheca long, narrow, sub-tubular, occupying almost entire internode. Adcauline hydrothecal wall adnate to hydrocladium, abcauline wall sinuous with posterior hump followed by a concavity then smoothly expanding to margin, a short internal septum passing up into hydrotheca from posterior hydrocladial septum. Hydrothecal margin perpendicular to hydrocladial axis, produced in a forward concave curve to meet hydrocladium; a short, pointed anterior rostrum. Median nematotheca truncated, digitate, free of hydrotheca, with three circular orifices, one just above junction with the abcauline hydrothecal wall, one intermediate, on a short slightly displaced mound and one terminal. Lateral nematotheca with two orifices (visible only at some angles of view) and a basal opening to hydrocladium.

Remarks. The species is fully described by Ritchie (1911) and Bale (1915). Bale was unsure whether his species (as Cladocarpella multiseptata ) from Queensland was identical with Cladocarpus bathyzonatus from New South Wales; the present material leaves no doubt that the two are conspecific.

Comparison of the present material with the few measurements given by the above authors shows it to be a little smaller in critical dimensions but as the differences may be due to methods of measurements it is not considered significant. The margins of many hydrothecae are slightly irregularly crenulate as described by Ritchie (1911).

Distribution. Southern Queensland, New South Wales; a first record for the Great Australian Bight. Insert Fig. 8

FIGURE 8A–I.

8A. Aglaophenia calycifera Bale, 1914 , hydrocladial internode with hydrothecae. 8B–F. Aglaophenia sinuosa Bale, 1888 . B, fertile colony. C, hydrothecae. D, hydrotheca, anterior view. E, median nematotheca and anterior rostrum. F, lateral nematotheca.

8G–I. Cladocarpus bathyzonatus Ritchie, 1911 . G, hydrotheca. H, median nematotheca showing three circular orifices. I, lateral nematotheca with two orifices.

Hydrocladium

internode length 640–720 maximum depth 68–80 Hydrotheca

length 480–504 width at margin 208–224 length of anterior cusp 40–42 Nematotheca

length, median 120–124 length, lateral 108–116