Gillichthys, Cooper, 1864

Gillichthys View in CoL clade

A number of oxudercine genera are distributed along the Pacific coast of Central and Northern America that seem to form a distinct clade within the Acanthogobius lineage of the gobioid phylogeny as depicted in Agorreta et al. (2013). Te American genera are here informally combined in a clade named for the genus Gillichthys . Tis Gillichthys clade contains the genera Clevelandia Eigenmann & Eigenmann, 1888 , Eucyclogobius Gill, 1862 , Evermannia Jordan, 1895, Gillichthys Cooper, 1864 , Ilypnus Jordan & Evermann, 1896, Lepidogobus Gill, 1859, Lethops Hubbs, 1926 , Quietula Jordan & Evermann, 1895, and Typhlogobius Steindachner, 1879 . Many of these genera are monospecific; others contain only few species. Otoliths are shown from all genera except Lethops , for which reference is made to Welton (2015; as Gobiidae indet.): Clevelandia ios ( Jordan & Gilbert, 1882) ( Fig. 45a–b View Fig ), Eucyclogobius newberryi (Girard, 1856) ( Fig. 45e–h View Fig ), Evermannia sp. [possibly E. longipinnis (Steindachner, 1879) ] ( Fig. 45i View Fig ), Evermannia erici Bussing, 1983 ( Fig. 45j View Fig ), Evermannia panamensis Gilbert & Starks, 1904 ( Fig. 45k–l View Fig ), Evermannia zosterura ( Jordan & Gilbert, 1882) ( Fig. 45m View Fig ), Gillichthys mirabilis Cooper, 1864 ( Fig. 46a–c View Fig ), Gillichthys seta (Ginsburg, 1938) ( Fig. 46d View Fig ), Lepidogobius lepidus (Girard, 1858)

( Fig. 46f View Fig ), Typhlogobius californiensis Steindachner, 1879

( Fig. 46g View Fig ), Ilypnus gilberti (Eigenmann & Eigenmann, 1889) ( Fig. 46h–i View Fig ), Quietula ycauda (Jenkins & Evermann, 1889) ( Fig. 46k View Fig ), and Quietula guamasiae (Jenkins & Evermann, 1889) ( Fig. 46m –n View Fig ).

Te otoliths in this group fall into two more or less well-defined morphological groups. One morphotype is characterized by a convex, relatively smooth inner face, a shallow sulcus, which is usually somewhat morphologically reduced in various ways, and a narrow ventral furrow that curves around the sulcus and joins up with a narrow, furrow-like dorsal depression. Tis highly distinctive morphological group combines the genera Clevelandia , Evermannia , Gillichthys , Ilypnus , and Quietula . Te second morphotype bears less recognizable features. Its otoliths are usually high-bodied, with a flat inner face, a broad ventral furrow connected to a relatively broad dorsal depression, and a morphologically reduced sulcus of variable size. Tis morphological group contains the genera Eucyclogobius , Lepidogobius , Lethops , and perhaps Typhlogobius . None of the taxa in this clade shows a subcaudal iugum.

Most of the fishes in the Gillichthys clade inhabit shallow coastal to estuarine environments. Gillichthys mirabilis is well known for its facultative air-breathing ( Graham & Wegner, 2010; Todd & Ebeling, 1966), and species of Quietula may also possess this ability ( Todd & Ebeling, 1966). Typhlogobius is a blind goby living secretively under rocks, in holes in rocks, and in kelp beds in shallow water ( Froese & Pauly, 2023). Lethops also has reduced eyes and lives under rocks and in kelp canopies ( Froese & Pauly, 2023). Other species of the Gillichthys clade inhabit coastal waters, mudflats, and lagoons, and some occur in brackish water and estuaries.