Solenoscyphus, Galea, 2015

Galea, Horia R., 2015, Two new genera and nine new species of hydroids (Cnidaria: Hydrozoa) from off New Caledonia, European Journal of Taxonomy 135, pp. 1-19 : 7-8

Genus Solenoscyphus gen. nov.

urn:lsid:zoobank.org:act:B69365F9-2052-4A94-8AF4-2456E46DA678

Diagnosis

Colonies of various sizes and shapes, from irregularly branched to pinnate, with either mono- or polysiphonic stems; cladia always monosiphonic. Hydrothecae long, tubular, with either straight or curved axes, adnate for less than half their length to the internodes; bases as complete septa; opercula filmy and rounded in shape, with indistinct points of attachment, clearly deciduous. Perisarc either smooth or finely and densely striated. Gonothecae unknown.

Type species

Solenoscyphus candelabrum sp. nov.

Etymology

From the Greek σωληνΟΕΙΔής, meaning "tubular", and σκύΦΟς, meaning "cup", to characterize the shape of the hydrothecae. It is a masculine noun.

Remarks

Unlike other sertulariid genera whose hydrothecae are provided with either an adaxial ( Abietinaria Kirchenpauer, 1884 , Diphasia Agassiz, 1862 , Idiellana Cotton & Godfrey, 1942 , and Papilionella Antsulevich & Vervoort, 1993 ) or an abaxial ( Salacia Lamouroux, 1816 and Thuiaria Fleming, 1828 ) opercular flap ( Bouillon et al. 2006), the new genus possesses a deciduous operculum with no definite point of attachment.

In this respect, it shows similarities with both Caledoniana gen. nov. and Staurotheca Allman, 1888 , and this may prove to be equally true for Gigantotheca Vervoort & Watson, 2003 as well. As shown above, Caledoniana gen. nov. is characterized by the presence of huge hydrothecae, a situation not met with in any of the three species described below. On the other hand, Staurotheca comprises a majority of species exhibiting a characteristic arrangement of the hydrothecae in decussate groups, although in a few cases they are either subopposite ( S. amphorophora Naumov & Stepanjants, 1962 , S. australis Peña Cantero et al., 1997 , and S. vervoorti El Beshbeeshy, 2011 ) or decidedly alternate ( S. abyssalis Peña Cantero & Vervoort, 2003 and S. profunda Peña Cantero & Vervoort, 2003 ). In addition, the hydrothecae of most species of Staurotheca are deeply immersed in both the stem and side branches; they characteristically curve outwards and their bases are often incomplete septa. Moreover, the colony shape in that genus is radically different, ranging from bush-like (with no distinct stems) to fan-shaped or tree-like ( Peña Cantero & Vervoort 2003a). Unlike the tropical Solenoscyphus gen. nov., Allman’s (1888) genus is essentially Antarctic, with a few species also occurring in the sub-Antarctic and some localities in South America ( Peña Cantero & Vervoort 2003a).

Key to species

1. Free part of hydrothecae curved upward ………………………………… S. candelabrum sp. nov.

– Free part of hydrothecae straight …………………………………………………………………2

2. Perisarc striated throughout, apex of hydrotheca swollen ……………………… S. striatus sp. nov.

– Perisarc smooth, hydrotheca isodiametric throughout ……………………… S. decidualis sp. nov.