Acryptolaria corniformis Naumov and Stepanjants, 1962

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 : 243-245

Acryptolaria corniformis Naumov and Stepanjants, 1962

( Figures 5 , 15C , 17D ; Table V)

Acryptolaria corniformis Naumov and Stepanjants 1962, p 74 , Figure 2 ; Stepanjants 1979, p 51, Plate 9 Figures 1–3 .

Material examined

Holotype: ZIRAS 1 /10322, Ob Sta. 44A, 65 ° 509030 S, 128 ° 279 E, 18 March 1956, 320 m, silty sand, one distal stem fragment ca 20 mm long, without coppinia (in slide).

Description

‘‘A small fragment of a colony (2 cm long) with polysiphonic caulus and alternative ramifications’’ ( Naumov and Stepanjants 1962, p 73). Branches in a slight zigzag.

Hydrothecae alternately arranged in approximately one plane. Hydrotheca horn-shaped, diameter gradually decreasing from aperture to basal part. Hydrotheca slightly curved abcaulinarly; basal half to two-thirds of adcauline wall adnate to internode. Adcauline wall slightly convex; abcauline wall slightly concave. Hydrothecal aperture circular, strongly directed upwards, forming an angle of ca 35 ° with longitudinal axis of branch. Rim even, sometimes with few short renovations.

Coppinia not observed.

Remarks

The material available consists of a microslide preparation; nematocysts are extremely difficult to find. However, putative nematocysts were seen.

Naumov and Stepanjants (1962) indicated that A. corniformis is allied with A. crassicaulis , being different in the larger dimensions of the hydrothecae and the greater length of the free adcauline part in A. corniformis . Stepanjants (1979) again pointed out the similarity between A. corniformis and A. crassicaulis , but differentiated both species by the smaller hydrothecae, more curved longitudinal axis, and less pronounced difference between the diameters of the aperture and basal part in A. crassicaulis . Gravier-Bonnet (1979), however, considered both species conspecific based on the habit of the colony and measurements. After examining the type material of both species, we consider that they constitute two valid, clearly distinguishable species (see below under the discussion of A. crassicaulis ).

Distribution

Off Sabrina Coast ( Antarctica), 289 m depth (cf. Naumov and Stepanjants 1962; Stepanjants 1979).

Figures

Figure 1. Acryptolaria abies (Allman, 1877). (A) Part of branch showing hydrothecal arrangement; (B–F) hydrothecae. (A–C, E) From the paralectotype; (D) from the lectotype; (F) from MCZ 45714. Scale bar: 1 mm (A); 400 Mm (B–F).

Figure 2. Acryptolaria angulata (Bale, 1914). (A–C) Hydrothecae. All drawings from the holotype. Scale bar: 400 Mm.

Figure 3. Acryptolaria bulbosa (Stechow, 1932). (A) Part of branch showing hydrothecal arrangement; (B–D) hydrothecae. All drawings from the holotype. Scale bar: 400 Mm.

Figure 5. Acryptolaria corniformis Naumov and Stepanjants, 1962. (A) Branch fragment showing hydrothecal arrangement; (B, C) hydrothecae. All drawings from the holotype. Scale bar: 1 mm (A); 400 Mm (B, C).

Figure 15. Hydrothecal arrangement in Acryptolaria. (A) A. abies; (B) A. conferta; (C) A. corniformis; (D) A. crassicaulis; (E) A. flabellum; (F) A. gracilis. Scale bar: 500 Mm (A, B, D, E); 250 Mm (C); 100 Mm (F).

Figure 17. Shape of hydrotheca in Acryptolaria. (A) A. abies; (B) A. angulata; (C) A. conferta; (D) A. corniformis; (E) A. crassicaulis; (F) A. flabellum. Scale bar: 250 Mm.