Taxonomic revision of the genus Sertularella (Cnidaria: Hydrozoa) from southern South America and the subantarctic, with descriptions of five new species Author Horia R. Galea Author Dirk Schories Author Verena Häussermann Author Günter Försterra text Revue suisse de Zoologie 2017 2017-09-30 124 2 255 321 journal article 31805 10.5281/zenodo.893519 10de215a-77ca-4e81-8c6b-a603108c4181 0035-418 893519 Sertularella vervoorti El Beshbeeshy, 2011 Fig. 18E ; Table 27 Sertularella vervoorti El Beshbeeshy, 2011 : 151 , fig. 48. – Watson & Vervoort, 2001 : 167, fig. 9. – Soto Àngel & Peña Cantero, 2015 : 996, fig. 7J-K. Sertularella cylindritheca . – Vervoort, 1972 : 126, fig. 39A. – Stepanjants, 1979 : 90, pl. 14 fig. 5A [non Sertularella cylindritheca ( Allman, 1888 ) = Sertularelloides cylindritheca ( Allman, 1888 ) ]. Material examined: ZMH C11552; FRV Walther Herwig , Stn. 327, Argentine Shelf, off Provincia de Santa Cruz, -51.18333° -56.95000°, 225 m; 29.06.1966; sterile, fragmentary colony (fragments 0.5-1.5 cm long) [material studied by El Beshbeeshy (2011) ]. Fig. 18. (A-D) Sertularella valdiviae Stechow, 1923b (continued). Hydrothecae from ANT XIX/5 ID.91 (A), ZSM 20050522 (B) and ZSM 20050521 (C). Gonothecae from the latter source (D). (E) Sertularella vervoorti El Beshbeeshy, 2011 , internode with hydrotheca. Scale bars: 200 μm (A-C, E), 500 μm (D). Description: Erect, though flaccid, up to 3.5 cm high colonies arising from creeping stolon. No definite main stem, the original stem branching several times subdichotomously; whole colony monosiphonic in habit. Both stems and branches divided into long, curved, slender internodes through distinct, oblique nodes; a hydrotheca, or a hydrotheca and one or two lateral, indistinct apophysis(es) immediately below its base; lower order branches arising not laterally, but almost perpendicular (in front or rear side) from their higher order counterparts. Hydrothecae strongly shifted to one side of the colony; very large, tubular, adnate to the corresponding internode for only a short part of their adaxial length, then curving outwards; abaxial wall almost straight for most of its length, slightly expanded below aperture; free adaxial wall gently curving basally, then straight; perisarc thin and smooth throughout; margin with 4 small, pointed cusps separated by shallow, semicircular embayments; renovations occasional; a 4-flapped operculum; hydranths with 18-20 filiform tentacles. Gonothecae arising from below the hydrothecal bases; elongated-ovoid, tapering basally, walls transversely-wrinkled; aperture distal, large, 4-cusped, and provided with a 4-flapped operculum. Dimensions: See Table 27 . Table 27. Measurements of Sertularella vervoorti El Beshbeeshy, 2011 , in μm.

El Beshbeeshy (2011)	Watson & Vervoort (2001)
Internode
- length	2425-5145	2925-3500
- diameter at node	278-394	330-350
Hydrotheca
- free adaxial length	1554-1855	2375-2625
- adnate adaxial length	-	-
- abaxial length	1345-1624	2050-2475
- maximum width	-	-
- diameter at aperture	626-858	800-1000
Gonotheca
- total length	-	1990-2250
- maximum width	-	800-1100

Remarks: The gonothecae of this species were described by Watson & Vervoort (2001) , and subsequently found by Soto Àngel & Peña Cantero (2015) . Distribution: Argentina – Provincia de Buenos Aires [scattered records from offshore waters ( El Beshbeeshy, 2011 )]; Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [off the NE coast of Isla de los Estados ( Vervoort, 1972, as S. cylindritheca )]. Falkland Is. – off the NE coast ( El Beshbeeshy, 2011 ). Scotia Arc – Burdwood Bank, South Georgia ( Soto Àngel & Peña Cantero, 2015 ). Tasmanian seamounts ( Watson & Vervoort, 2001 ).