Acryptolaria sp.

Cantero, A. L. Peña, Svoboda, A. & Vervoort, W., 2004, Antarctic hydroids (Cnidaria, Hydrozoa) of the families Campanulinidae, Lafoeidae and Campanulariidae from recent Antarctic expeditions with R. V. Polarstern, with the description of a new species, Journal of Natural History 38 (18), pp. 2269-2303 : 2281-2285

publication ID	https://doi.org/ 10.1080/00222930310001647361
persistent identifier	https://treatment.plazi.org/id/002E150C-FFDA-055E-FD9E-FCC39C7A4BE5
treatment provided by	Felipe
scientific name	Acryptolaria sp.
status

Treatment

Acryptolaria sp. ( figure 2A, B View FIG )

Material examined. ANT II- 4 Stn 450, one stem ca 115 mm high (RMNH- Coel. 30777); ANT IX- 3 Stn 207, a few stems up to 120 mm high, the largest with coppinia (RMNH-Coel. 30778).

Description. Erect, polysiphonic stems up to 120 mm high. Branches up to fifth order observed. Branching approximately in one plane, usually alternate; in ANT II- 4 Stn 450 with some anastomoses. Hydrothecae alternately arranged approximately in one plane and partially overlapping. Hydrotheca ( figure 2A, B View FIG ) almost completely cyclindrical, but diameter distinctly decreasing at proximal part (145–177 M m diameter at base). Hydrotheca curved outwards, with one-quarter to one-half of its adcauline wall free; 419–693 M m and 1127–1369 M m length of free and adnate parts, respectively. Abcauline wall concave, especially at distal half, 1336–1562 M m long; adcauline wall convex, except the basalmost part, 1578–1820 M m long. Hydrothecal aperture circular (274–290 M m diameter); rim even and sometimes provided with a few short renovations. Cnidome composed of two kinds of nematocysts: small and large unidentified nematocysts (18–2166.5–7.5 M m).

Female coppinia fusiform, consisting of gonothecae closely set together around stem or main branches. Coppinia deprived of defensive tubes. Gonotheca fusiform, with a funnel-shaped aperture.

Remarks. Our material resembles several species described in Acryptolaria [e.g. A. conferta (Allman, 1877) ]. However, it is undesirable to assign it to any of the known species of the genus until a revision of the genus has been made and information concerning the cnidome has been provided.

Ecology and distribution. Our material originates from depths between 208 and 450 m. Acryptolaria sp. is used as substratum by other hydroids ( Billardia subrufa and Lafoea gaussica ). It was found with coppinia in March. It was collected in the Weddell Sea area (off Ronne Ice Shelf and off Fimbul Ice Shelf, Princess Astrid Coast).

Genus Filellum Hincks, 1868

Filellum antarcticum ( Hartlaub, 1904) View in CoL

( figures 2C–F View FIG , 3 View FIG , 4 View FIG ; table 1) Lafoea antarctica Hartlaub, 1904: 11 View in CoL , pl. 2 figure 2 View FIG ; Vanhöffen, 1910: 311, figure 31. Reticularia antarctica: Totton, 1930: 160–161 , figure 17. Filellum antarcticum: Millard, 1964: 10 View in CoL ; 1975: 177, figure 58G–H; 1978: 192;

Bouillon et al., 1995: 52; Peña Cantero et al., 1998: 300–301.

Material examined. Polarstern material: ANT II-4 Stn 310, several hydrothecae on Billardia subrufa , with coppinia (RMNH-Coel. 30782); ANT II-4 Stn 341, numerous hydrothecae on B. subrufa and Stegella lobata , with coppinia (RMNH-Coel. 30783); ANT II-4 Stn 438, numerous hydrothecae on B. subrufa , with coppinia (RMNH-Coel. 30785); ANT II-4 Stn 474, numerous hydrothecae on B. subrufa , with coppinia (RMNH-Coel. 30788);?ANT II-4 Stn 524, numerous hydrothecae on Halecium sp. , with coppinia (RMNH-Coel. 30790); ANT VIII-5 Stn 16-399, several hydrothecae on B. subrufa , with coppinia (RMNH- Coel. 30794); ANT VIII-5 Stn 16-405, numerous hydrothecae on B. subrufa ,? Opercularella belgicae , and axis of gorgonian, with coppinia (RMNH-Coel. 30796); ANT VIII-5 Stn 16-456, a few hydrothecae on B. subrufa , with coppinia (RMNH-Coel. 30816); ANT VIII-5 Stn 16-459, several hydrothecae on B. subrufa , with coppinia (RMNH-Coel. 30799); ANT VIII-5 Stn 16-486, several hydrothecae on B. subrufa , with coppinia (RMNH-Coel. 30803); ANT IX-3 Stn 135, numerous hydrothecae on B. subrufa , with coppinia (RMNH-Coel. 30805).

Deutschen Southpolar Expedition: Gauss Station , 65 ‡ 21’S 86 ‡ 06’E, 385 m depth. Museum für Naturkunde der Humboldt-Universität zu Berlin (neotype, ZMB Cni 14222) .

Description. Stolonal colonies composed of stolons creeping on substratum and giving rise to sock-shaped hydrothecae ( figure 2E, F View FIG ), adnate to substratum to a varied degree. Adnate part of hydrothecae provided with striae on dorsal side; striation highly variable. Hydrothecal aperture circular, rim even. Cnidome composed of two kinds of nematocysts, small (5.2–5.962.6–2.9 M m) and large ones (11.7–14.365.2–5.9 M m).

Coppinia composed of a set of firmly adpressed gonothecae surrounded by a fence of long defensive tubes usually curved towards the centre of the gonothecal mass in such a way that they constitute a nest or corbula ( figure 4A, C, D View FIG ). Defensive tubes forked or unforked, provided with distal, circular aperture ( figure 4A–D View FIG ). Gonotheca tubular, basally truncated and with a distal, unraised, circular aperture ( figure 4E, F View FIG ), usually on a slightly raised, cone-shaped part. Eggs remaining on gonothecae, immersed in a sort of nourishing mass.

Remarks. The type material of Lafoea antarctica Hartlaub, 1904 is lost, so we found it necessary to indicate a neotype for this species. Since Vanhöffen (1910) was the first author to describe fertile material of this species, we have chosen his material as the neotype for Filellum antarcticum (ZMB Cni 14222).

Vanhöffen’s (1910) material consists of stolonal colonies formed by stolons that creep on the substratum and irregularly give rise to hydrothecae. Most hydrothecae are sock-shaped with a small portion adnate to the substratum ( figure 2C View FIG ); a few hydrothecae, however, are completely free ( figure 2D View FIG ). The free part of the hydrotheca is upwardly directed to a varied degree. The hydrothecae are slightly wider at aperture. The hydrothecal aperture is circular, the rim even, usually with few, long renovations. The dorsal portion of the adnate part of hydrotheca is provided with a few striae. The cnidome is composed of two sorts