Halisiphonia Allman, 1888

Marques, Antonio Carlos, Cantero, Alvaro Luis Peña & Migotto, Alvaro Esteves, 2006, Revision of Halisiphonia Allman, 1888 (Cnidaria, Hydrozoa, Hebellidae), with comments on its taxonomic position, Journal of Natural History 40 (17 - 18), pp. 1047-1062 : 1048-1049

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https://doi.org/10.1080/00222930600845259

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scientific name

Halisiphonia Allman, 1888
status

 

Genus Halisiphonia Allman, 1888 View in CoL

Halisiphonia Allman 1888, p 30 View in CoL –31; Stepanjants 1979, p 55.

Type species: Halisiphonia megalotheca Allman, 1888 , by monotypy.

Diagnosis

Colonies stolonal with creeping hydrorhiza. Hydrothecae tubular or slightly conical, deep, borne on pedicels of varied length; pedicels arising singly from hydrorhiza and almost imperceptibly merging into hydrothecae; diaphragm present, though inconspicuous in some hydrothecae, thin and membranous. Operculum and nematophores absent.

Gonangia developing medusae. Gonothecae solitary, laterally compressed, pedicellate, arising from hydrorhiza.

Remarks

Allman (1888, p 30) established the genus Halisiphonia based on H. megalotheca (see Allman 1888, p 31, Plate 16, Figure 1, 1a View Figure 1 ), a species he thought lacking a diaphragm, and of which he stated the hydrothecal cavity was ‘‘directly continuous with that of the peduncle or stolon’’. Therefore, since its erection, the presence of a diaphragm is generally not mentioned in the diagnosis of Halisiphonia species. Halisiphonia nana Stechow, 1921 was also described as lacking a diaphragm ( Stechow 1921, p 228; 1925, p 452, Figure 22). In both cases, however, the diaphragm was originally overlooked: for H. megalotheca the presence of a diaphragm was confirmed by Billard (1910, p 5), who examined the holotype; for H. nana , we found a very thin, membranous diaphragm, although it was indistinct or even absent in some hydrothecae. Kramp (1932, p 40) comments: ‘‘a diaphragm may be more or less distinctly developed or altogether lacking in this genus’’. Indeed, Kramp (1937, 1956) described two other species of Halisiphonia , H. arctica and H. galatheae , respectively, in which he recognized a diaphragm. For the former, the diaphragm is stated as being ‘‘a very delicate membrane with a central opening’’ ( Kramp 1937, p 38), whereas for the latter, it was said that ‘‘a very slight internal thickening may sometimes indicate the base of the hydrotheca, and in a few cases an extremely delicate diaphragm may be discerned’’ ( Kramp 1956, p 17). Similarly, Vervoort (1966, p 121, for H. galatheae ) states, ‘‘in some thecae there is an extremely delicate membrane basally of the place of attachment, in some theca present as a hollowed meniscus, in others as a tight membrane. It may represent a very thin diaphragm’’. Bouillon (1985) regarded the feature as present in only some species and Calder (1991, p 31) implied the existence of a diaphragm or annular thickening for Hebellinae (his rank), including Halisiphonia .

The inconspicuousness of the diaphragm makes some of the Halisiphonia species superficially resemble stolonal colonies of Lafoea , a genus usually characterized by erect colonies (occasionally stolonal, see Calder 1991, p 36) and gonothecae aggregated into coppinia. Lafoeids with coppinia are included within the subfamilies Lafoeinae A. Agassiz, 1865 and Zygophylacinae Quelch, 1885, although the genus Cryptolarella , with single gonothecae, is exceptionally included among the Eulafoeinae [sic] sensu Bouillon (1985) (cf. Marques et al. 2005). In the past, lafoeids with solitary gonophores were assigned to the subfamily Hebellinae Fraser, 1912 . The subfamily Hebellinae has been raised to family level (e.g. Schuchert 2001, 2003), and kept separate from the Lafoeidae , a hypothesis corroborated by the presence of medusa buds in the gonothecae of H. arctica ( Schuchert 2001) ; an opinion with which we concur.

In H. arctica , H. galatheae , and H. megalotheca the gonotheca is spatulate, being round or pear-shaped in frontal view, strongly compressed in lateral view, truncated distally, and attached to the hydrorhiza by a short pedicel (see below). However, according to the original description and single record, H. spongicola ( Haeckel 1889, p 77, Plate 4, Figure 9) has gonotheca ‘‘not compressed or spatuliform, with a slit-shaped opening; their transverse section and the distal opening are circular’’. Nonetheless, the frontal outline of its gonotheca seems similar to those of the other Halisiphonia .

The gonothecal profile of Halisiphonia recalls that of Hebella and Scandia , two genera assigned to the family Hebellidae (plus Bedotella , see Marques et al. 2004, 2006); in Halisiphonia and Bedotella , however, the gonotheca is strongly laterally compressed.

Allman GJ. 1888. Report on the Hydroida dredged by H. M. S. Challenger during the years 1873 - 76. Part II-the Tubulariinae, Corymorphinae, Campanulariinae, Sertulariinae, and Thalamophora. Report on the scientific results of the voyage of H. M. S. Challenger during the years 1873 - 76 23 (70): i-xix, 1 - 90, Plates 1 - 40.

Billard A. 1910. Revision d'une partie de la collection des hydroides du British Museum. Annales des Sciences Naturelles, Zoologie (Serie 9) 11: 1 - 67.

Bouillon J. 1985. Essai de classification des hydropolypes-hydromeduses (Hydrozoa-Cnidaria). Indo-Malayan Zoology 2: 29 - 243.

Calder DR. 1991. Shallow-water hydroids of Bermuda. The Thecatae, exclusive of Plumularioidea. Royal Ontario Museum, Life Sciences Contributions 154: i-iv + 1 - 140, Figures 1 - 60.

Fraser CM. 1912. Some hydroids of Beaufort, North Carolina. Bulletin of the Bureau of Fisheries, United States 30: 337 - 387.

Haeckel E. 1889. Report on the deep-sea Keratosa collected by H. M. S. Challenger during the years 1873 - 76. Report on the scientific results of the voyage of H. M. S. Challenger during the years 1873 - 1876, Zoology 32: 1 - 92, Plates 1 - 8.

Kramp PL. 1932. The Godthaab Expedition 1928. Hydroids. Meddelelser om GrOnland 79 (1): 1 - 86, Figures 1 - 34.

Kramp PL. 1937. Polypdyr (Coelenterata), II. Gopler. Danmarks Fauna 43: 1 - 223, Figures 1 - 90.

Kramp PL. 1956. Hydroids from depths exceeding 6000 meters. Galathea Report 2: 17 - 20, Figures 1 - 7.

Marques AC, Altuna A, Pena Cantero AL, Migotto AE. 2004. Re-description of Bedotella armata from Biscay Bay, northern Spain, the type species of Bedotella Stechow, 1913 (Cnidaria, Hydrozoa, Lafoeidae), with comments on its taxonomic position. Hydrobiologia 530 / 531: 223 - 230.

Marques AC, Pena Cantero AL, Migotto AE. 2005. Revision of the genus Cryptolarella Stechow, 1913 (Lafoeidae, Leptothecata, Hydrozoa). Journal of Natural History 39: 709 - 722.

Marques AC, Pena Cantero AL, Migotto AE. 2006. An overview of the phylogeny of the families Lafoeidae and Hebellidae (Hydrozoa, Leptothecata), their composition and classification. Invertebrate Systematics 20: 43 - 58.

Quelch JJ. 1885. On some deep-sea and shallow-water Hydrozoa. Annals and Magazine of Natural History 16: 1 - 20, Plates 1, 2.

Schuchert P. 2001. Hydroids of Greenland and Iceland (Cnidaria, Hydrozoa). Meddelelser om GrOnland, Bioscience 53: 1 - 184, Figures 1 - 138, Appendices 1 - 3.

Schuchert P. 2003. Hydroids (Cnidaria, Hydrozoa) of the Danish expedition to the Kei Islands. Steenstrupia 27: 137 - 256, Figures 1 - 82, Appendices 1, 2.

Stechow E. 1921. Ueber Hydroiden der Deutschen Tiefsee-Expedition, nebst Bemerkungen uber einige andre Formen. Zoologischer Anzeiger 53: 223 - 236.

Stepanjants SD. 1979. Gidroidy vod Antarktikh I Subantarktikh. Rezultaty Biologieskikh Issledovaniy Sovietskikh Antarkticheskikh Ekspedtsiy, Akademiya Nauk SSSR, Leningrad 22 (30): 1 - 200, Figures 1 - 9, Plates 1 - 25, 3 colour figures on 2 plates.

Vervoort W. 1966. Bathyal and abyssal hydroids. Galathea Report 8: 97 - 173.

Gallery Image

Figure 1. Halisiphonia arctica Kramp, 1932. (A) Hydrotheca, lateral view; (B) portion of a colony; (C) hydrothecal diaphragm; (D) base of hydrotheca showing desmocytes; (E) gonothecae, lateral view. Scale bars: 200 Mm (A); 1.0 mm (B); 25 Mm (C); 100 Mm (D); 500 Mm (E).

Kingdom

Animalia

Phylum

Cnidaria

Class

Hydrozoa

Order

Leptothecata

Family

Hebellidae