Acryptolaria minuta Watson, 2003

Peña Cantero, Alvaro L., Marques, Antonio C. & Migotto, Alvaro E., 2007, Revision of the genus Acryptolaria Norman, 1875 (Cnidaria, Hydrozoa, Lafoeidae), Journal of Natural History 41 (5 - 8), pp. 229-291 : 256-258

Acryptolaria minuta Watson, 2003

( Figures 11 , 16C ; Table XI)

Acryptolaria minuta Watson 2003, p 163 –164, Figure 13 A–C.

Material examined

Holotype: NMV F 91338 , Macquarie Island, Stn 130, 52 ° 59.49– 53 ° 029 S, 159 ° 599– 159 ° 58.29 E, 31 January 1999, 1422 m, one slide.

Description

‘‘Small infertile colony of five small stems, two branched … Tallest stem 9 mm high, broken off at tip, 3.5 mm wide at base; stems branched once in one plane; branched stems arising from a small matted plug of stolons, simple stems from junction of stolonal tubes; taller stems with up to four polysiphonic tubes intergrown and rather contorted proximally, becoming linear distally; polysiphonic tubes running almost to top of stems; stems lightly fascicled; branches given off beside a hydrotheca’’ ( Watson 2003, p 163).

Hydrothecae alternately arranged in one plane. Hydrotheca tubular, long and thin, diameter slightly larger at free part, clearly decreasing at basal part. Hydrotheca strongly curved abcaulinarly, ca two-thirds adnate to internode. Adcauline wall convex; abcauline wall markedly concave. Hydrothecal aperture circular, upwards and abcaulinarly directed, forming an angle of 60–90 ° with long axis of branches. Rim even, with few renovations.

Coppinia not observed.

Remarks

According to Watson (2003, p 164), ‘‘their smaller dimensions and sparsely branched habit matches no other known species of Acryptolaria ’’. She considered this species similar to A. patagonica (see remarks for this name under the description of A. operculata below) in habit, though considerably smaller. Watson also indicated that ‘‘The slightly everted margin of the hydrotheca resembles A. conferta minor Ramil and Vervoort, 1992 but it is smaller and the hydrothecae are frontally directed in contrast to those of A. conferta minor which, according to these authors, lie in the plane of ramification of the branches’’ ( Watson 2003, p 164).

Acryptolaria minuta is similar to A. minima in the size of the hydrothecae (cf. Table XV), though in the former the hydrothecae are larger and thinner, strongly curved abcaulinarly, and with a much larger proportion of their adcauline wall free. Moreover, the nematocysts are much smaller (25–27X9–10 Mm in A. minima ).

The material described as Acryptolaria conferta var. australis by Ritchie (1911) and Totton (1930) (the latter only the material from Sta. 96) might belong to this species.

Distribution

Acryptolaria minuta is known only from the Macquarie Island area (52 ° 59.49– 53 ° 029 S, 159 ° 599– 159 ° 58.29 E), where it was collected at a depth of 1422 m on dead primnoid gorgonian .

Figures

Figure 11. Acryptolaria minuta Watson, 2003. (A–C) Branch fragments showing shape and arrangement of hydrothecae. All drawings from the holotype. Scale bar: 400 Mm.

Figure 13. Acryptolaria pulchella (Allman, 1888). (A) Branch fragment showing hydrothecal arrangement; (B–E) hydrothecae; (F) coppinia fragment (dorsal view); (G) gonotheca (lateral view). All drawings from the holotype. Scale bar: 1 mm (A); 400 Mm (B–G).

Figure 16. Hydrothecal arrangement in Acryptolaria (continued). (A) A. longitheca; (B) A. minima; (C) A. minuta; (D) A. operculata; (E) A. pulchella; (F) A. tortugasensis. Scale bar: 500 Mm (A, D); 250 Mm (B, C, E, F).