Gobiosoma, Girard, 1858

Gobiosoma View in CoL Group sensu Tornabene et al., 2016

Otoliths of the fishes in the Gobiosoma group are distinguished from those of the Microgobius group by the absence of a subcaudal iugum. Te Gobiosoma group contains a large number of often very small species. Small otoliths in small fishes are more easily destroyed during exposure to formalin than larger otoliths, and therefore the coverage of extant otoliths of the genera and species in the Gobiosoma group is less comprehensive than in the Microgobius group. Otoliths are known from 16 of the 27 genera currently recognized in the Gobiosoma group. Otoliths are not known from the genera Aboma , Birdsongichthys , Carrigobius , Cryptopsilotris , Evermannichthys , Ophiogobius , Paedovaricus , Pariah , Pinnichthys , Robinsichthys , and Vomerogobius . Tese are mostly small, monotypic genera, many of them living in specific reef environments that offer little chance for the fossilization of otoliths.

Rüber et al. (2003) and Tornabene et al., (2016, 2022) have undertaken extensive phylogenetic analyses of the Gobiosoma group. Tornabene et al. (2016) recognized two subgroups, the Barbulifer and the Nes subgroups. Tornabene et al. (2022) recognized an additional subgroup, the Robinsichthys subgroup. Rüber et al. (2003) did not formulate subgroups but instead recognized nine clades in the Gobiosomatini , two in the Microgobius group (the Bollmannia and the Microgobius clades) and seven in the Gobiosoma group (the Nes , Aboma , Barbulifer , Gobiosoma , Risor , Tigrigobius , and Elacatinus clades). Te phylogenies of the three publications are generally congruent but differ somewhat in details.

With some variations, we have followed here the grouping in clades by Rüber et al. (2003), primarily because it is easier to relate to the otolith findings. We are aware that certain clades or subgroups are not represented by otoliths for the reasons mentioned above, i.e., the Aboma clade of Rüber et al. (2003) and the Robinsichthys subgroup of Tornabene et al. (2022). Only the Barbulifer and Nes clades of Rüber et al. (2003) are comprehensively represented. Most other clades or subgroups are represented by a limited number of taxa. Tis means that species recognition in the fossil record is hampered, except for the Barbulifer and Nes clades and a few other characteristic genera, and therefore many otoliths must remain in open nomenclature for the time being.