Sphaerocoryne Pictet, 1893

Calder, Dale R., 2010, Some anthoathecate hydroids and limnopolyps (Cnidaria, Hydrozoa) from the Hawaiian archipelago 2590, Zootaxa 2590 (1), pp. 1-91 : 66-67

Genus Sphaerocoryne Pictet, 1893

Sphaerocoryne Pictet, 1893: 9 .

Type species. Sphaerocoryne bedoti Pictet, 1893 , by monotypy.

Diagnosis. Sphaerocorynid hydroids stolonal, usually with long hydrocauli; hydranths with capitate tentacles all simple.

Gonophores free medusae, arising in clusters on hydranth just distal to tentacles. Medusae with exumbrellar nematocysts scattered; manubrium of adult quadrate in cross-section; marginal tentacles four, capitate, equally developed at liberation, with intermediate nematocyst aggregations in bands.

Remarks. Petersen (1990) assigned Linvillea Mayer, 1910b , a replacement name for Corynitis McCrady, 1859 (an invalid junior homonym of Corynitis Geyer, 1832 [ Lepidoptera ] and Corynitis Menge, 1854 [Ara- neae]), to the synonymy of Sphaerocoryne Pictet, 1893 . A problem arises from that proposed synonymy because the widely overlooked Corynetes Haeckel, 1879 , an unjustified emendation of Corynitis McCrady, 1859 but nevertheless an available name [ICZN Art. 33.2] and with the same type species (ICZN Art. 67.8), is a senior objective synonym of Linvillea and a name with priority over Sphaerocoryne when the two are considered congeneric. Reversal of Precedence (ICZN Art. 23.9) cannot be applied to conserve Sphaerocoryne in this case because Corynetes has been used as a valid name at least once since 1899 (e.g. by Hartlaub 1913: 242). An earlier usage of the name Corynetes exists for a coleopteran by Paykull (1798), but that name has been entered in the Official Index of Rejected and Invalid Generic Names in Zoology (ICZN Opinion 604). In being no longer available, Corynetes Paykull, 1798 does not invalidate Corynetes Haeckel, 1879 .

Two solutions exist in resolving the nomenclatural threat to Sphaerocoryne . If it and Corynetes are considered congeneric, a case should be submitted to the International Commission on Zoological Nomenclature asking for a ruling on the merits of conserving Sphaerocoryne . If not, Corynitis agassizii McCrady, 1859 can be removed from Sphaerocoryne and reassigned to Corynetes . Corynitis agassizii is known to differ from Sphaerocoryne bedoti Pictet, 1893 , type species of Sphaerocoryne , as follows: (1) medusa buds arise amongst rather than distal to tentacles on hydranths of hydroids; (2) nematocysts on the exumbrella of medusae are arranged in eight exumbrellar tracks rather than being scattered; (3) advanced medusa buds and juvenile medusae have only two opposite tentacles rather than four equally developed ones; (4) nematocysts on tentacles of medusae are aggregated in the form of warts rather than in bands; (5) the manubrium is reportedly more distinctly cruciform in adult medusae; (6) abaxial ocelli of medusae appear before or shortly after liberation instead of much later in development (Yamada and Konno 1973; Calder 1988). By restricting Sphaerocoryne to S. bedoti Pictet, 1893 , type species of the genus, and provisionally to S. peterseni Bouillon, 1984a (a species known only from its medusa stage), the genus can be retained as valid. That provisional step is taken here, and the diagnosis of Sphaerocoryne given above reflects the change. Affinities of Corynetes arcuata Haeckel, 1879 , an inadequately characterized species known only from the medusa, are unclear. It has been considered of doubtful validity ( Kramp 1961; Bouillon et al. 2006). Sarsia coccometra Bigelow, 1909 from the eastern tropical Pacific, a medusa regarded as a species of Sphaerocoryne by Petersen (1990: 213), was retained in the corynid genus Sarsia Lesson, 1843 by Schuchert (2009).