Contributions to Zoology, 68 (2) 83-93 (1999) SPB Academic Publishing bv, The Hague 1919 Phylogenetic analysis of the Antarctic genus Oswaldella Stechow, (Hydrozoa, Leptomedusae, Kirchenpaueriidae) Alvaro+L. Peña+Cantero¹ & Antonio+C. Marques² 1 Departamento de Biologia Animal, Facultad de Ciencias Biologicas, Universidad de Valencia, Dr. 2 Moliner 50, 46100 Burjassot, Valencia, Spain. E-mail: [email protected]; Departamento de Biologia, Sdo Av. Bandeirantes Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Paulo. 3900, 14040-901, Ribeirao Preto, SP, Brazil. E-mail: [email protected] Keywords: Hydrozoa, Kirchenpaueriidae, Oswaldella, Antarctica, systematics, cladistics are Cairns on Abstract hydrozoans publications by (1984) Stylasteridae, Marinopoulos (1992) using muddled methods on Eudendriidae (see Marques, 1996, for A carried out known of the cladistic study was on species a and further comments), and (1993, Antarctic reply Marques characteristically genus Oswaldella, adopting as out- Eudendriidae. other included in the Kirchen- 1996), on Other stud- groups some genera family phylogenetic ies include those of Boero & Gravier- paueriidae. The analysis resulted in a cladogram with low CI Bouillon, in between be which no relationship genera can depicted. Bonnet (1986), Petersen (1990), and Cunningham However, the of ofthe hypothesis monophyly genus Oswaldella & Buss (1993). is corroborated, being supported in our cladogram by five The family Kirchenpaueriidae and more broadly synapomorphies (although all are homoplastic with other taxa the taxaPlumulariida and Leptomedusae havebeen or reversed within the species of the genus). The basal the of one (Boero, ofthe but three subject only phylogenetic study relationships genus are uncertain, species groups & This is remarkable are within the O. Bouillon Piraino, 1996). distinguishable Oswaldella: 1) incognita group, the O. antarctica and clade formed because these when with antho- 2) group, 3) a by (O. groups, compared O. blanconae O. number garciacarrascosai, O. elongata ( (O. gracilis medusans, have a larger of potential char- herwigi, Oswaldella two)))). sp. acters available for phylogenetic analyses. This paucity of phylogenetic studies may be due to a lack of general typological revisions of leptome- Contents dusan groups, the traditionalism of systematists of this group (cf. Marques, 1996), misconceptions Abstract 83 concerning polymorphisms, and incomplete knowl- Introduction 83 edge about life cycles in the group (cf. Migotto, Cladistic methods 84 1998). Choice of out-groups 84 The genus Oswaldella Stechow, 1919a is one Results and discussion 85 of the most diversified genera ofAntarctic Characters adopted 85 hydroids. Of 21 known 20 endemic to the Phylogenetic hypothesis and discussion 87 some species, are Acknowledgements 91 Antarctic Region (the only exception, Oswaldella References 92 herwigi El Beshbeeshy, 1991, is Patagonian). This suggests an Antarctic origin of the genus (cf. Pena Cantero & Vervoort, 1998), and its striking distri- Introduction bution suggests a possible monophyletic origin. The has been in several genus investigated recent Phylogenetic studies on hydrozoan taxa have been works (Stepan’yants, 1979; El Beshbeeshy, 1991; few in number. In general, the systematics of the Pena Cantero & Vervoort, 1995, 1996, 1997, 1998; is still Pena Garcia Carrascosa & group based mainly on essentialistic prin- Cantero, Vervoort, 1995; ciples. & Examples of parsimony studies applied to Pena Cantero, Svoboda Vervoort, 1997), and a Downloaded from Brill.com10/07/2021 08:18:05AM via free access 84 A.L. Pena Cantero & A.C. Marques - Antarctic Hydrozoa solid morphological knowledge of the taxon is bers 19, 20, 22). The systematics of the family available. Other genera of Kirchenpaueriidae, a Kirchenpaueriidae is confusing, and we consid- less well family of worldwide distribution, are ered that any informationabout the monophyly of the here. and would be known, complicating analyses genera species groups important to The goals of this study were to synthesize the guide future studies. characters of previous revisions of the genus in the Oswaldella phylogenetic hypotheses, to test Choice of out-groups validity of some species (such as those presented as Oswaldella sp. one and Oswaldella sp. two by The major question whether to choose one or sev- Pena Cantero & Vervoort, 1995), and to discuss eral taxa that could be used as out-groups for this the of characters and further was related to the applicability some analysis polymorphisms among implications of the phylogenetic hypothesis in the species included in the family Kirchenpaueriidae, evolution of the genus. and to the lack of a general recent revision for this family. Bouillon’s (1985) synopsis, which five in the constitutes recognized genera family, a Cladistic methods unique compendium for classification ofthe group. The genus Halicornopsis Bale, 1882, includes both in The phylogenetic analysis was performed follow- two known species, distributed Australian ing the major principles proposed by Hennig (1966), waters. Halicornopsis elegans Lamarck, 1816 and and general methods described by Forey et al. H. avicularis Bale, 1882 are poorly known spe- (1992), Marques (1996), Ferrarezzi & Marques cies that have been recorded only a few times. (1997) and Simoes, Marques, Mello & Anelli Halicornopsis is characterized by the denticulated (1997). rim of the hydrothecal aperture (Bouillon, 1985), The characters were ordered whenever infor- a feature also shared with some genera ofthe family mation about ontogeny was present, or when the Aglaopheniidae. Because of this we decided not existence of of the consider this within the contiguity similarity among states to genus potential out- of the character clear. The for Oswaldella due to its uncertain was parsimony analy- groups posi- sis 2.2 was performed using TreeGardener v. tion. The (Ramos, 1997) emulating Hennig86 (Farris, 1988), genus Ophinella Stechow, 1919b, is mo- employing the heuristic algorithms “mh*;bb*”. The notypic. The only known species, O. parasitica strict (Sokal & Rohlf, 1981) and semi-strict G.O. Sars, 1874, is distinguishable by its long for bear (Bremer, 1990) consensus trees were derived urticating organs that nematocysts on their built the most parsimonious trees. The matrix was capitate tips. The position of the genus is uncer- the using as many “out-groups” as possible (see tain; Stechow (1919b) and Bedot (1923) placed about the in whereas exposition taxa adopted as out-groups below), genus Kirchenpaueriidae, Sars (1874, the Allman to assure a more efficient optimization of char- original description as Ophiodes parasitica), acters (Nixon & Carpenter, 1993). Firstly, an (1883), Bonnevie (1899), and Jaderholm (1909) unrooted network was considered, and this was a placed the species in Haleciidae, drawing simi- rooted larities the 1874. posteriori using ontogenetic or «out-group» to genus Hydrodendron Hincks, & De useless principles (Nixon Carpenter, 1993; Pinna, These facts led us to consider Ophinella a 1994). Whenever necessary in the discussion, we out-group for the analysis. adopted the group+ artifact, i.e., the whole clade The genus Pycnotheca Stechow, 1919b, is char- is indicated of mark to its acterized the of abcauline intra- by the addition a “+” by presence an most basal thecal The includes group (Amorim, 1982). septum (Bouillon, 1985). genus Although autapomorphic characters of the out- two species: P. mirabilis (Allman, 1883), which rela- is herein of group taxa are not informative for sorting adopted as an out-group Oswaldella, the of the not included tionships among species in-group, we and P. producta (Bale, 1882; as out- The choice decided to include these characters as well (num- group). of only one of the species of Downloaded from Brill.com10/07/2021 08:18:05AM via free access Contributions to Zoology, 68 (2) - 1999 85 the related the total available infor- Results and discussion genus was to mation about them. Bouillon Characters The last genus recognized as valid by adopted with (1985) was Kirchenpaueria Jickeli, 1883, some 20 nominal species. According to Bouillon (1985: The characters used in this study are presented otherwise noted, information the 169; herein translated to English), it is character- below. Unless on ized as follows “Branched or unbranched, monosi- following taxa was obtained as follows: Oswaldella & phonic or polysiphonic colonies. Hydrothecal spp. (Pena Cantero Vervoort, 1995, 1996, 1997, marginal rim non-denticulated. Hydrotheca with- 1998; Pena Cantero et al., 1995, 1997); Pycnotheca 1975); out intrathecal septum. Unforked hydrocladia. mirabilis (Millard, Kirchenpaueria spp. & 1995 Mesial nematotheca present or not, when present (Medel Vervoort, and personal observa- inferior in Ventromma & either superior or or both positions”. tions); spp. (Ramil Vervoort, 1992; & Hence, it is clear that, at least in an essentialistic Medel Vervoort, 1995, and personal observa- view of and Naumovia et ah, 1997, (by now independent a phylogenetic ap- tions); (Stepan’yants proach), Kirchenpaueria is mainly characterized and personal observations). All data concerning summarized in the matrix of Table by the lack of the diagnostic features of the other the characters are characters in 1. genera of the family. 1; some are represented Fig, Bouillon considered Ventromma Stechow, 1923 a of Neverthe- Table I. Matrix used for the cladistic analysis of Oswaldella junior synonym Kirchenpaueria.