Cryptolaria tortuosa, Watson, 2018

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 : 3

Cryptolaria tortuosa sp. nov.

Figure 1B–E

Material examined. SAM H2332, holotype colony; three microslides ( SAM H2567, H2568, H2569) from holotype colony. West of South Australia – Western Australia border, trawl, 180 m, coll: R. Southcott 1/7/1988 .

Description. Flabellate infertile colony 90 mm high and 80 mm wide without hydrorhiza. Stem 3 mm wide at base, heavily fascicled. Branching irregularly complex with frequent swellings and intergrowths, polysiphonic tubes more or less straight but entwined at intervals, running almost to tips of branches.

Hydrothecae subopposite to subalternate on younger monosiphonic branches, tubular, widening slightly from floor to margin, curving gently outwards, adcauline wall adnate for most of length, free part variable in length, abcauline wall almost straight to concave. Diaphragm usually not visible; margin circular, rim thin and very fragile.

Nematothecae numerous throughout colony except at tips of branches; directed outwards from branch at various angles, pedicel thick with two or three strong twists, body barrel-shaped to cylindrical, length very variable, margin circular, thin.

Colony (preserved material) greyish white.

Hydrotheca

length, floor to margin 260–400 adnate length 240–360 diameter at margin 120–150 Nematotheca

overall length 320–460 maximum width 140–152 width of pedicel 56–76 Remarks. Species considered were: Cryptolaria prima Busk, 1857 , Cryptolaria exserta Busk, 1858 , Cryptolaria pectinata Allman, (1888) , Cryptolaria triserialis Fraser, 1913 , Cryptolaria profunda Naumov, 1960 , Cryptolaria rigida ( Fraser, 1940) and Cryptolaria spinosa Millard, 1980 . However, the nematothecal pedicel of none of these species resembles the twisted pedicel of Cryptolaria tortuosa .

The preserved material is fragile, readily shedding branches. The subopposite to subalternate arrangement of the hydrothecae is visible only on the few intact distalmost branches (Fig. 1C). The margins of most hydrothecae that extend beyond the polysiphonic tubes of the branch are crushed. The diaphragm above the floor of the hydrotheca is indistinct and is visible only a in a few hydrothecae.

Etymology. Named for the twisted pedicel of the nematotheca.