Obelia irregularis Fraser, 1943a

Calder, Dale R. & Choong, Henry H. C., 2018, Names of hydroids (Cnidaria, Hydrozoa) established by Charles McLean Fraser (1872 - 1946), excluding those from Allan Hancock Expeditions, Zootaxa 4487 (1), pp. 1-83: 69-70

publication ID

https://doi.org/10.11646/zootaxa.4487.1.1

publication LSID

lsid:zoobank.org:pub:524B23B9-8EAA-4BD6-8937-A1B8F1C057B9

persistent identifier

http://treatment.plazi.org/id/0392282A-FFA2-FFA1-AEC1-58B51B24FC67

treatment provided by

Plazi

scientific name

Obelia irregularis Fraser, 1943a
status

 

Obelia irregularis Fraser, 1943a 

Obelia irregularis Fraser, 1943a: 77  , pl. 16, fig. 3.

Holotype. MCZ-IZ 9013: St Kitts and Nevis, off St Kitts, 17°19’27”N, 62°50’30”W, USCSS Blake, 250 fm (457 m), 14 January 1879, two fragments of a colony, ca. 3 cm high, in poor condition, coll. A. Agassiz, labelled “ type ”; 70% ethanol.GoogleMaps 

Type locality. St. Kitts and Nevis: off St Kitts , 17°19’27”N, 62°50’30”W, 250 fm (457 m) ( Fraser 1943a).GoogleMaps 

Current status. Valid.

Remarks. Obelia irregularis  was described by Fraser (1943a) in a collection sent on loan to him from the MCZAbout MCZ. As with other species in that collection, no name-bearing types were designated for it. The species is not represented in the Fraser Hydroid Collection at the RBCMAbout RBCM, and the only known type material of O. irregularis  is that returned by Fraser to the MCZAbout MCZ (MCZ-IZ 9013). The count number (“1”) accompanying the type ( MCZAbout MCZ –IZ 9013), and Fraser’s (1943a) description (“Colony 3 cm. in height…”), indicate that the species was described from a single hydroid. Although two fragments were found in the type collection examined at the MCZAbout MCZ, they are considered parts of the same colony. The specimen is therefore taken to be the holotype by monotypy ( ICZN Art. 73.1.2). Another hydroid recorded as O. irregularis  at the MCZAbout MCZ (MCZ-CNID 77), from Grand Manan, New Brunswick, Canada, is not part of the type series. That identification is dubious given the much different environmental conditions of the collection locality.

In his account of O. irregularis, Fraser (1943a)  observed and briefly described hydrothecae and gonothecae. The holotype examined here is now in poor condition, and neither of these structures could be distinguished with certainty.

Obelia irregularis  is listed as a valid species in WoRMS, a conclusion that seems justified at present given the location, depth, and distinctive morphology of the hydroid as described by Fraser (1943a). In particular, the hydrothecal rim was said to have “…10 regularly rounded teeth [cusps], the division between them extending deep into the hydrothecal wall.” Hydrothecal pedicels are wavy but not noticeably annulated. While gonothecae were described by Fraser, the character of the gonophores remains unknown. Uncertainty therefore exists about the generic assignment of the species.

MCZ

Museum of Comparative Zoology

RBCM

Royal British Columbia Museum

Kingdom

Animalia

Phylum

Cnidaria

Class

Hydrozoa

Order

Leptothecata

Family

Campanulariidae

Genus

Obelia

Loc

Obelia irregularis Fraser, 1943a

Calder, Dale R. & Choong, Henry H. C. 2018

2018
Loc

Obelia irregularis Fraser, 1943a : 77

Fraser, 1943a : 77