Molecular Phylogenetics of the Clingfishes (Teleostei: Gobiesocidae)—Implications for Classification

Abstract

Gobiesocidae are a moderate-sized family (currently 182 species, 51 genera) of predominantly coastal marine fishes, commonly referred to as clingfishes. Depending on the classification adopted, the species and genera of clingfishes are organized either across ten subfamilies, based on a classification scheme introduced in the 1950s (''traditional'' classification, comprising Aspasminae, Cheilobranchinae, Chorisochisminae, Diademichthyinae, Diplocrepinae, Gobiesocinae, Haplocylicinae, Lepadogastrinae, Protogobiesocinae, and Trachelochisminae), or just two subfamilies, in a classification scheme adopted only recently (''reduced'' classification, comprising Cheilobranchinae and Gobiesocinae). We investigated the phylogenetic relationships among members of the family Gobiesocidae using both mitochondrial and nuclear DNA sequence data to assess whether the alternative classification schemes (traditional and reduced) are compatible with inferred evolutionary relationships. Phylogenetic hypotheses are derived from maximum-likelihood and Bayesian analyses of a seven-gene concatenated dataset (2 mitochondrial and 5 nuclear markers; 4,857 bp) compiled from individuals representing 82 (of 182) species, 42 (of 51) genera, and 10 (of 10) subfamilies of the Gobiesocidae. Although our investigation provides strong support for the monophyly of the Gobiesocidae, multiple subfamilies of the traditional classification (Aspasminae, Diademichthyinae, Diplocrepinae, Gobiesocinae, and Trachelochisminae), one subfamily of the reduced classification (Gobiesocinae), and multiple genera (Aspasmichthys, Cochleoceps, Lepadogaster, and Lepadichthys) are resolved as non-monophyletic groups. Based on our results and the results of previous studies, we recommend a systematic reassignment of genera between subfamilies, of which we recognize nine: Cheilobranchinae, Chorisochisminae, Diademichthyinae, Diplocrepinae, Haplocylicinae, Gobiesocinae, Lepadogastrinae, Protogobiesocinae, and Trachelochisminae. Membership of the Lepadogastrinae is unchanged from previous usage; the Cheilobranchinae are expanded to contain additional genera from southern Australia, including those placed previously in the Aspasminae (Nettorhamphos and Posidonichthys) and the Diplocrepinae (Barryichthys, Cochleoceps, and Parvicrepis); the Aspasminae are placed in the synonymy of the Diademichthyinae and all genera placed in the former (excluding Modicus and Posidonichthys) are transferred to the latter; the Diplocrepinae are restricted to Diplocrepis; Eckloniaichthys scylliorhiniceps is transferred from the Gobiesocinae to the Chorisochisminae; Gobiesocinae are restricted to the New World members of this group (Acyrtops, Acyrtus, Arcos, Derilissus, Gobiesox, Rimicola, Sicyases, and Tomicodon); the Haplocylicinae are expanded to include additional genera from New Zealand (Gastrocyathus, Gastrocymba, and Gastroscyphus); the Protogobiesocinae are expanded to accommodate three genera of deep water

First record of the Kermadec Clingfish, Flexor incus Conway, Stewart & Summers, 2018 (Gobiesocidae), from New Caledonia and Australia

“…Although Flexor was recovered as the sister taxon to Aspasmichthys ciconiae (Jordan & Fowler, 1902) in Conway et al's (2020) study, the former is superficially similar to Pherallodus Briggs 1955 [including Pherallodus indicus (Weber, 1913)] and Propherallodus Shiogaki & Dotsu 1983[including Propherallodus briggsi Shiogaki & Dotsu, 1983, Propherallodus longipterus Fujiwara & Motomura, 2018b, and Propherallodus smithi (Briggs, 1955]. These three genera can be distinguished from other members of the Diademichthyinae sensu Conway et al (2020) in having a "double" adhesive disc (sensu Briggs 1955) and gill membranes free from the isthmus. Flexor differs from Pherallodus and Propherallodus by the teeth shape in both jaws, disc papillae (also see below), and head sensory canal pores (see Conway et al 2018a: 95).…”

“…In their original description of F. incus, Conway et al (2018a) pointed out that the higher classification of clingfishes proposed by Briggs (1955) may require revision. More recently, the classification scheme of Briggs (1955) was revised by Conway et al (2020), who recognized nine subfamilies in the Gobiesocidae based on the results of a molecular phylogenetic investigation. According to them, the monotypic genus Flexor is assigned to the subfamily Diademichthyinae, which they expanded to include several additional genera formerly included in the Aspasminae, Diplocrepinae, and Protogobiesocinae by Briggs (1955) and Fricke et al (2016).…”

“…The family Gobiesocidae is a moderate-sized fish family, commonly called clingfishes because all members of the family, except for the shore eel genus Alabes Cloquet, 1816, have a well-developed ventral adhesive disk with which they adhere tightly to the substrate (Briggs 1955;Conway et al 2020). Most members of the family inhabit intertidal and subtidal zones in the Atlantic and Indo-Pacific oceans, and a small number of species occur in deeper waters down to 570 m or in freshwater streams in the neotropics (Briggs 1955;Conway et al 2017a;Hastings and Conway 2017).…”

A new species of the genus Acyrtus on the eastern Pacific: A cornerstone for the evolution and biogeography of the genus

“…The species Sicyases sanguineus was used as the out‐group, following the recent phylogenetic study of Conway et al . (2020). More specific information on the used individuals including their associated GenBank information is summarized in Supporting Information table S1.…”

“…The family has a worldwide distribution typically in marine neritic environments, occurring mainly in tropical and temperate waters (Briggs, 1993). Currently, clingfishes are composed of 10 subfamilies, 51 genera and 185 species (Conway et al ., 2020; Fricke et al ., 2021). In particular, the subfamily Gobiesocinae includes 79 species and nine genera distributed in marine and freshwater environments of the eastern Pacific and western Atlantic (WA) (Fricke et al ., 2021; Froese & Pauly, 2019).…”