Acryptolaria operculata Stepanjants, 1979

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 : 258-261

Acryptolaria operculata Stepanjants, 1979

( Figures 12 , 16D , 18D , 19E ; Table XII)

Acryptolaria operculata Stepanjants 1979, p 52 , Plate 9 Figure 5A, B .

Acryptolaria patagonica El Beshbeeshy 1991, p 67 –70, Figure 14 [nomen nudum].

Acryptolaria patagonica El Beshbeeshy in Watson 2003, p 162–163, Figure 12 A–C; Vervoort and Watson 2003, p 51–53, Figure 7 A–G. Material examined

Paratype: ZIRAS 2 /9463, Zund Sta. 194, 43 ° 569 S, 59 ° 089 W, 27 May 1974, 140 m, one basally broken stem fragment ca 40 mm long, without coppinia .

Acryptolaria patagonica , one slide from Sta. 330, 40 ° 579 S, 56 ° 579 W, 23 February 1971, 980 m (Walter Herwig expedition 1971).

Description

Stem fragment ca 40 mm long, basally broken. No information concerning habit is available; other than its irregular branching.

Hydrothecae alternate, in two planes, making an obtuse angle. Hydrotheca tubular, fusiform; maximum diameter approximately in the middle of hydrothecal length, decreasing distinctly towards basal part. Hydrotheca curved abcaulinarly, half to twothirds of adcauline wall adnate to internode. Adcauline wall convex; abcauline wall concave. Hydrothecal aperture circular, directed upwards, forming an angle of 55–75 ° with long axis of branch. Rim even, with few short renovations.

Coppinia not observed.

Remarks

Acryptolaria operculata is characterized by the size and arrangement of the hydrothecae. It is the species with the largest hydrothecae (cf. Table XV) and it is also characterized by the hydrothecal arrangement in two planes, making an obtuse angle, though this feature is also present in other species of the genus (e.g. A. tortugasensis , see below).

Stepanjants (1979) also characterized this species by the presence of a one-flap operculum, pointing out the particular position of this species amongst the Lafoeidae . However, after studying many colonies of Acryptolaria , we have observed that the presence of that circular flap, in spite of being irregular, is quite common amongst species of Acryptolaria , being also common in species of another lafoeid genus, Grammaria . That valve should not be considered as an opercular apparatus in the sense of that present in other families of hydroids (e.g. Sertulariidae or Campanulinidae ). By contrast, it seems to constitute a sort of deciduous structure to temporally protect the polyps when they are in a state of inactivity or regeneration, as has already postulated for other groups such as Staurotheca (cf. Peña Cantero et al. 1997).

In his PhD dissertation on hydrozoans from the Patagonian shelf, El Beshbeeshy (1991) included the description of 22 new species, as well as many re-descriptions and some nomenclatural considerations. Many subsequent papers (e.g. Peña Cantero et al. 1997; Peña Cantero and Marques 1999; Vervoort and Watson 2003; Watson 2003) have used the names employed by El Beshbeeshy (1991). However, according to the International Code of Zoological Nomenclature (1999), a thesis is not to be taken as published for the purposes of zoological nomenclature, and therefore the specific names proposed by El Beshbeeshy (1991) should be considered nomina nuda. According to the Code ‘‘A nomen nudum is not an available name, and therefore the same name may be made available later for the same or a different concept; in such a case it would take authorship and date [Arts. 50, 21] from that act of establishment, not from any earlier publication as a nomen nudum ’’.

Indeed, many nominal species of El Beshbeeshy were subsequently described by other authors and, in this case, these should become the authors of the valid names. Nevertheless, Article 50.1.1. of the Code establishes that ‘‘however, if it is clear from the contents that some person other than an author of the work is alone responsible both for the name or act and for satisfying the criteria of availability other than actual publication, then that other person is the author of the name or act. If the identity of that other person is not explicit in the work itself, then the author is deemed to be the person who publishes the work’’. El Beshbeeshy (1991) described A. patagonica as a new species; the species was again reported by Watson (2003) and Vervoort and Watson (2003), and both papers clearly gave the authority of the species to El Beshbeeshy. Therefore, the species is herein assumed as ‘‘ Acryptolaria patagonica El Beshbeeshy in Watson, 2003 ’’. In any case, the species nominally described as A. patagonica would be characterized by its large hydrothecae and the arrangement of the hydrothecae in two planes, forming an obtuse angle. According to El Beshbeeshy (1991), A. patagonica differs from A. operculata by the absence of operculum, the shorter free part of the adcauline wall (672–858 Mm), and the larger diameter at hydrothecal base (232–324 Mm). Nevertheless, we have re-examined some slides of the material described by El Beshbeeshy and there are no differences between it and the type of A. operculata . Additionally, both have similar dimensions of their nematocysts (13.5–14X4.5–5 Mm and 8X3–3.5 Mm in A. patagonica ). Therefore, we consider A. patagonica conspecific with A. operculata .

Vervoort and Watson (2003) also assigned material from New Zealand to A. patagonica and, again, the description fully agrees with the type material of A. operculata . Vervoort and Watson (2003) indicated that the most significant character in A. patagonica is that the conspicuous hydrothecae are not in one plane, but point obliquely frontally. As we have demonstrated before, this feature is also found in the type material of A. operculata , and it is clearly described by Stepanjants (1979) in her original description.

Distribution

Acryptolaria operculata seems to be a shelf and bathyal species, having been found at depths between 98 ( El Beshbeeshy 1991) and 1422 m ( Watson 2003). Watson (2003) found it on primnoid gorgonians. It is known to be distributed in sub-Antarctic waters, from the Patagonian shelf ( Stepanjants 1979; El Beshbeeshy 1991), New Zealand ( Vervoort and Watson 2003), and Macquarie Island ( Watson 2003).

Figures

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 7. Acryptolaria flabellum (Allman, 1888). (A, B) Branch fragments showing hydrothecal arrangement; (C, D) hydrothecae. All drawings from the holotype. Scale bar: 1 mm (A, B); 400 Mm (C, D).

Figure 12. Acryptolaria operculata Stepanjants, 1979. (A, B) Branch fragments showing shape and arrangement of hydrothecae. All drawings from the paratype. Scale bar: 1 mm.

Figure 14. Acryptolaria tortugasensis Leloup, 1935. (A–F) Branch fragments showing shape and arrangement of hydrothecae. All drawings from the holotype. Scale bar: 1 mm (A); 400 Mm (B–F).

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).

Figure 18. Shape of hydrotheca in Acryptolaria (continued). (A) A. gracilis; (B) A. longitheca; (C) A. minima; (D) A. operculata; (E) A. pulchella; (F) A. tortugasensis. Scale bar: 100 Mm (A, C, F); 250 Mm (B, D, E).

Figure 19. Shape of gonothecae: (A) Acryptolaria conferta; (B) A. minima. Detail of different structures: (C) bottleneck-shaped basal part of hydrotheca in A. gracilis; (D) opercular structure in A. minima; (E) opercular structure in A. operculata; (F) longitudinal striae in hydrotheca of A. flabellum; (G) intrathecal cusp of A. tortugasensis. Scale bar: 100 Mm (A, B, D, F, G); 50 Mm (C); 250 Mm (E).