Sertularella sanmatiasensis El Beshbeeshy, 1991

Galea, Horia R., Häussermann, Verena & Försterra, Günter, 2009, New additions to the hydroids (Cnidaria: Hydrozoa) from the fjords region of southern Chile, Zootaxa 2019, pp. 1-28 : 12-13

Sertularella sanmatiasensis El Beshbeeshy, 1991

(fig. 3C–E, table 3)

Sertularella sanmatiasensis El Beshbeeshy, 1991: 188 , fig. 47. – Peña Cantero, 2006: 939, fig. 3L. – Peña Cantero & Gili, 2006: 767. – Peña Cantero, 2008: 459, fig. 2C. – Peña Cantero & Vervoort, 2009: 87, fig. 2B.

Sertularella polyzonias – Blanco, 1984: 37, pls 31–36 figs 69–81 [not Sertularella polyzonias ( Linnaeus, 1758) ].

Sertularella gigantea – Billard, 1906: 12, fig. 4 (not Sertularella gigantea Mereschkowsky, 1878 ).

Sertularella picta – Stepanjants, 1979: 85, pl. 15 fig. 4 [not Sertularella picta ( Meyen, 1834) ].

Sertularella sp. 1 Peña Cantero & García Carrascosa, 1995: 55, figs 23A–F, 24A–F.

Material examined. Stn. 7 – 22.02.2008, 15.6 m, A128: two fragments of stems (1.5 and 2.8 cm high, respectively), each with one gonotheca.

Type locality. San Matias Gulf, Argentina.

Remarks. The scarcity of the present material does not allow a new description of this species. Briefly, our specimens are characterized by the following features: 1) the colonies are relatively small, monosiphonic, each stem has one lateral branch (not shown); the basal part is missing in both stems; 2) the nodes are distinct and slope alternately left and right; 3) the hydrothecae are barrel-shaped, swollen basally, narrower below the margin; 4) nearly half of the adcauline wall is adnate and its free part is smooth to slightly undulated; 5) three intrathecal projections of perisarc (one large abcauline and two smaller latero-adcauline), of variable development, are irregularly present below the hydrothecal aperture; 6) the gonothecae are elongate-ovoid, transversely wrinkled (6 and 7 wrinkles on each of the single gonothecae), with aperture mounted on short neck and surrounded by 3 and 4 projections of perisarc of varied development; 7) ca. 20 eggs are found inside the gonotheca.

This species forms erect, most probably monosiphonic colonies, with scarce, irregular branching ( Peña Cantero & Vervoort 2009), though a tendency to an alternate arrangement has already been noted ( Blanco 1984). The basal part of the caulus, missing in our material, is normally provided with up to 6 transverse annuli ( El Beshbeeshy 1991, Peña Cantero 2006). The basal stem internodes are longer than the proximal ones ( Blanco 1984). The two rows of hydrothecae are usually coplanar, but sometimes they are shifted towards one side of the stem/branch, forming an angle of about 90° between them ( Blanco 1984, El Beshbeeshy 1991, Peña Cantero & Vervoort 2009). The hydrothecal abcauline cusp is slightly more developed than remaining three, though not considerably longer ( Blanco 1984, El Beshbeeshy 1991). Renovations of the hydrothecal margin are normally present ( Billard 1906, Blanco 1984). Up to three internal projections of perisarc, inconstantly present even within the same colony, were observed by both Blanco (1984) and Peña Cantero & Garcia Carrascosa (1995). Tendrils were present in the material studied by Billard (1906), Blanco (1984), Peña Cantero (2006), the latter worker also mentions anastomoses with neighboring branches. Gonothecae of both sexes were observed by Blanco (1984); female are wider than male, and have more prominent apical projections. Sexual dimorphism was also noticed by Peña Cantero & Garcia Carrascosa (1995), who found large, smooth-walled gonothecae mounted upon a short pedicel, and smaller ones, without pedicel and having the distal half of the wall undulated.

El Beshbeeshy (1991) noted that the perisarc is bright orange, and that the tentacles of hydranth (18–20 in number) have a red-brown tinge.

Because Beshbeeshy’s 1991 paper is difficult to consult, some workers do not recognize his species names. However, this work appears to meet ICZN standards (W. Vervoort, pers. comm.), having been printed (“Gedruckt mit Unterstützung des Deutschen Akademischen Austauschdienstes”, i.e. Printed with the support of the German Academic Exchange Service) and distributed, albeit to a limited extent.

World distribution. Southern Argentina ( El Beshbeeshy 1991), Tierra del Fuego and Falkland Island ( Stepanjants 1979). For detailed records from the Antarctic seas, see Peña Cantero (2006, 2008) and Peña Cantero & Gili (2006).

Records from Chile. The present, first record of this species for Chile, is from the South of Chiloé Island.