Acryptolaria conferta ( Allman, 1877 )

Peña Cantero, Álvaro L., 2020, Species of Acryptolaria Norman, 1875 (Cnidaria: Hydrozoa) collected by US Antarctic and sub-Antarctic expeditions, Zootaxa 4767 (2), pp. 277-294 : 279

Acryptolaria conferta ( Allman, 1877)

( Figs 1A , 3A , 5A , 7A )

Cryptolaria conferta Allman, 1877: 17 , 19, 20, pl. 12, figs 6–10.

Acryptolaria conferta— Peña Cantero et al. 2007: 240–243 , figs 4, 15B, 17C, 19A, tab. IV; Soto Àngel & Peña Cantero 2015: 988, fig. 3c–d.

Acryptolaria cf. conferta— Peña Cantero & Vervoort, 2010: 279–280 , figs 4, 30; table 5.

Material examined. Eltanin: 9/740, stem fragment 14 mm long. Hero : 715/885, stem fragment 18 mm long.

Description. Hydrothecae alternate, more or less in one plane, in a distinct zigzag pattern. Hydrotheca tubular, free part roughly cylindrical; diameter smoothly decreasing basally at adnate part (almost indistinguishable at the most basal part). Hydrotheca curved outwards, adnate to internode for roughly two-thirds of its adcauline length. Adcauline wall convex, but straight, or even slightly concave, in basal third. Abcauline wall concave by the middle, practically straight at basal and distal third. A ring of desmocytes present at base of hydrotheca. Hydrothecal aperture circular, directed upwards and outwards. Rim even, sometimes with a few short renovations.

Measurements (in µm). Hydrothecae: abcauline wall 810–960, free part of adcauline wall 320–500, adnate part of adcauline wall 550–700, adcauline wall 870–1160, diameter at aperture 180–210, diameter at base 98. Cnidome (from Stn 715/885): larger microbasic mastigophores, range 22–23 x 9–10, mean 22.4±0.5 x 9.6±0.4 (n=10); ratio, range 2.2–2.6, mean 2.3±0.1 (n=10); smaller microbasic mastigophores 7 x 3.

Remarks. The material examined is in complete agreement with the holotype (see Peña Cantero et al. 2007) in colony structure, shape and size of hydrotheca, and size of nematocysts.

Peña Cantero & Vervoort (2010) recorded the species from the Loyalty Islands and New Calendonian waters, but with smaller hydrothecae and slightly larger nematocysts than in the holotype. The present study shows that the size of the nematocysts in their material falls within the range for the species; therefore, the remaining single difference would be the smaller hydrotheca. This, however, could be of minor importance since the hydrothecal size range has been demonstrated to be quite wide for some species of the genus (cf. Peña Cantero & Vervoort 2010).

Ecology and distribution. Acryptolaria conferta has been recorded at depths from 277 ( Soto Àngel & Peña Cantero 2015) to 860 m ( Peña Cantero & Vervoort 2010); present material from 493 to 677 m.

Acryptolaria conferta is certainly known from off Cojima, Cuba ( Allman 1877), Burdwood Bank ( Soto Àngel & Peña Cantero 2015) and likely from the Loyalty Islands and New Caledonian waters ( Peña Cantero & Vervoort 2010). Present material comes from off Staten Island (Tierra del Fuego) and west off South Georgia, both in the south-west Atlantic Ocean.

Figures

FIGURE 1. Branch fragments showing hydrothecal arrangement and shape of hydrothecae:A, Acryptolaria conferta (Allman, 1877); B, Acryptolaria crassicaulis (Allman, 1888); C, Acryptolaria flabellum (Allman, 1888); D, Acryptolaria minuta Watson, 2003; E, Acryptolaria operculata Stepanjants, 1979. (A from 715/885; B from 2/11; C from 22/1520; D from 27/1852; E from 715/885). Scale bar: 500 µm.

FIGURE 3. Hydrothecae: A, Acryptolaria conferta (Allman, 1877); B–C, Acryptolaria flabellum (Allman, 1888); D, Acryptolaria frigida Peña Cantero, 2014; E–F, Acryptolaria minuta Watson, 2003 (A from 715/885; B from 22/1520; C from 5/221; D from 2/2; E–F from 27/1852). Scale bar: 250 µm.

FIGURE 5. Hydrothecae: A, Acryptolaria conferta (Allman, 1877); B, Acryptolaria corniformis Naumov & Stepanjants, 1962; C, Acryptolaria crassicaulis (Allman, 1888); D, Acryptolaria flabellum (Allman, 1888); E, Acryptolaria frigida Peña Cantero, 2014; F, Acryptolaria longitheca (Allman, 1877); G, Acryptolaria minuta Watson, 2003; H, Acryptolaria sp. (A from 715/885; B from 27/1951; C from 2/11; D from 22/1520; E from 2/2; F from 27/1974; G from 27/1852; H from 6/339). Scale bar: 200 µm.

FIGURE 7. Nematocysts:A, Acryptolaria conferta (Allman, 1877); B, Acryptolaria flabellum (Allman, 1888); C, Acryptolaria frigida Peña Cantero, 2014; D, Acryptolaria longitheca (Allman, 1877); E, Acryptolaria operculata Stepanjants, 1979; F, Acryptolaria sp. (A from 715/885; B from 5/221; C from 2/2; D from 27/1974; E from 22/1595; F from 715/885). Scale bar: 10 µm.