Reconciling genealogical and morphological species in a worldwide study of the Family Hydractiniidae (Cnidaria, Hydrozoa)

Abstract

The Hydractiniidae are a family of globally distributed marine hydrozoans (class Hydrozoa, phylum Cnidaria). Despite being one of the most well‐studied families of the Hydrozoa, their genus and species‐level taxonomy is unsettled and disputed. The taxonomic difficulties of the Hydractiniidae are due to many inadequate species descriptions, a paucity of available morphological characters, many cryptic species, and the often‐extreme plasticity seen when colonies of the same species are found at different stages of growth or different environmental conditions. This confusion over species identity is especially important because some species of the family Hydractiniidae are well‐established model organisms for a wide array of studies ranging from gene expression to developmental biology and colony growth. Here we report the species‐level implications of 226 mitochondrial large ribosomal subunit (16S) rDNA sequences from around the world and 52 nuclear DNA sequences (Elongation Factor 1α) with the intent to reconcile described morphospecies with genealogical lineages. Our data show that Podocoryna carnea and P. exigua are distinct and geographically disjunct species, P. borealis is paraphyletic with respect to Podocoryna sp. from South Africa and P. bella from New Zealand. Podocoryna australis, from New Zealand form a distinct monophyletic group. Podocoryna from New England, New York and Florida all fall into a distinct monophyletic group (P. americana) and fail to support the existence of a distinct, P. selena in the Gulf of Mexico. Hydractinia pruvoti is the only species within the Podocoryna clade without fully formed medusae. We identify a Clava clade closely related to other algae dwelling Hydractiniidae. Our data do not recover Stylactaria inabai from Japan as a distinct species from S. misakiensis, and S. carcinicola as distinct from H. epiconcha. Also, 10 colonies identified as S. carcinicola fall into a distantly related clade that is close to the American S. hooperi. Finally, we identify Janaria mirabilis as the sister group to the H. echinata species complex and clarify the relationships between the H. echinata, H. symbiopollicaris, H. polyclina, H. symbiolongicarpus and H. [GM].

Additions to the hydroids (Cnidaria, Hydrozoa) of the Bay of Fundy, northeastern North America, with a checklist of species reported from the region

“…According to Miglietta et al (2009), preliminary molecular studies suggest that H. symbiopollicaris may be conspecific with H. polyclina. Confirmation of this conclusion is warranted, and both species are currently recognized as valid in WoRMS.…”

DNA barcoding of hydromedusae in northern Beibu Gulf for species identification

“…泛采纳为通用的标准条形码基因片段 (Hebert et al, 2004b;Ward et al, 2005;Hajibabaei et al, 2006;Ratnasingham et al, 2007) Shearer et al, 2002;Hellberg et al, 2006;Huang et al, 2008;McFadden et al, 2011)。然而, Sinniger等 母目和软水母目种类中表现得更为明显 (Shearer et al, 2002;Miglietta et al, 2009;Moura et al, 2011bMoura et al, , 2012 Collins et al, 2008;Moura et al, 2008;Leclère et al, 2009;Bucklin et al, 2011;Moura et al, 2012)。同 时, 它还常作为一种有效的分子标记, 用以区分形 态差异细微、 不可辨识或尚未描述的种类 Miglietta et al, 2009;Miranda et al, 2010;Moura et al, 2011a, b)。Schuchert等(2006, 2007, 2008a, b, 2009 …”

Five athecate hydroids (hydrozoa: anthoathecata) from south-eastern australia

“…There about 130 nominal species of Hydractiniidae, mostly recorded from the northern hemisphere, although many are inadequately described (Miglietta et al 2009). The only presently known Hydractinia from south-eastern Australia is H. betkensis (Watson 1978).…”