Freshwater gobies 30 million years ago: New insights into character evolution and phylogenetic relationships of †Pirskeniidae (Gobioidei, Teleostei)

Abstract

The modern Gobioidei (Teleostei) comprise eight families, but the extinct †Pirskeniidae from the lower Oligocene of the Czech Republic indicate that further families may have existed in the past. However, the validity of the †Pirskeniidae has been questioned and its single genus †Pirskenius has been assigned to the extant family Eleotridae in previous works. The objective of this study is to clarify the status of the †Pirskeniidae. Whether or not the †Pirskeniidae should be synonymised with the Eleotridae is also interesting from a biogeographical point of view as Eleotridae is not present in Europe or the Mediterranean Sea today. We present new specimens and reexamine the material on which the two known species of †Pirskenius are based (†P. diatomaceus Obrhelová , 1961; †P. radoni Přikryl, 2014). To provide a context for phylogenetically informative characters related to the palatine and the branchiostegal rays, three early-branching gobioids (Rhyacichthys, Protogobius, Perccottus), an eleotrid (Eleotris) and a gobiid (Gobius) were subjected to micro-CT analysis. The new data justify revalidation of the family †Pirskeniidae, and a revised diagnosis is presented for both †Pirskenius and †Pirskeniidae. Moreover, we provide for the first time an attempt to relate a fossil gobioid to extant taxa based on phylogenetic analysis. The results indicate a sister-group relationship of †Pirskeniidae to the Thalasseleotrididae + Gobiidae + Oxudercidae clade. Considering the fossil record, the arrival of gobioids in freshwater habitats in the early Oligocene apparently had generated new lineages that finally were not successful and became extinct shortly after they had diverged. There is currently no evidence that the Eleotridae was present in the European ichthyofauna in the past.

Diversity of gobioid fishes in the late middle Miocene of northern Moldova, Eastern Paratethys – part I: an extinct clade of Lesueurigobius look-alikes

“…Most notably among the morphological characters of †Katyagobius gen. nov., †Pseudolesueurigobius gen. nov., †Sarmatigobius gen. nov. and †Yarigobius gen. nov. are the presence of distally filamentous spines in the first dorsal fin, large numbers of soft rays in both the D2 and anal fin, a longish or lanceolate caudal fin comprising 16-17 segmented principal rays, and rounded, trapezoid-to-squarish sagittae with a ventral portion that is slightly wider than the dorsal portion. This combination of characters clearly separates the new fossil genera and species from all previously described fossil skeleton-based gobioids (e.g., Arambourg 1927;Carnevale et al 2006;Schwarzhans et al 2012Schwarzhans et al , 2017aGierl et al 2013;Reichenbacher 2015, 2017;Bannikov and Carnevale 2016;Reichenbacher et al 2018Reichenbacher et al , 2020Bradić-Milinović et al 2019), and also from all previously described otolith-based fossil gobioids (e.g., Nolf 2013;Agiadi et al 2013Agiadi et al , 2019Bratishko et al 2015;Lin et al 2015Lin et al , 2017Schwarzhans et al 2015Schwarzhans et al ,2020aReichenbacher et al 2019;van Hinsberg and Helwerda 2019). Their distinctive combination of skeleton-related characters also differentiates the new fossil taxa from the extant members of the Gobioidei (e.g., Miller 1986Miller , 2004Carpenter et al 1997;Carpenter and Niem 2001;Larson 2001;Murdy et al 2002;Ahnelt 2003;Ahnelt and Duchkowitsch 2004;Kovačić 2008;Carpenter and De Angelis 2016), whereas otolith data are not available for every extant species or genus due to the extraordinary species richness of the Gobioidei.…”

An integrative phylogenetic approach for inferring relationships of fossil gobioids (Teleostei: Gobiiformes)

“…Gobioidei belongs to Gobiiformes (sensu Thacker et al [10]), together with Kurtidae, Apogonidae, and Trichonotidae, and consists of nine families: Rhyacichthyidae, Odontobutidae, Milyeringidae, Eleotridae, Butidae, Thalasseleotrididae, Gobiidae, and Oxudercidae (= formerly Gobionellidae [1]), and the extinct †Pirskeniidae [11] ( Fig 1). Phylogenetic relationships within extant Gobioidei are generally well resolved based on molecular data [10,12,13].…”

“…In contrast, Gobioidei with six branchiostegal rays (6brG) form a paraphyletic group in molecular phylogenies [12,16], indicating that this condition is plesiomorphic within Gobioidei. The only gobioid that has seven branchiostegal rays, of which the last ray is expanded as is typical for Gobioidei (see [17]), is the genus †Pirskenius (denoted 7brG here), and phylogenetic analyses placed it within the paraphyletic 6brG [11]; see Fig 1. The closest living relatives of Gobioidei, the Apogonidae, Kurtidae, and Trichonotidae, all have seven branchiostegals and no expansion of the last branchiostegal ray [1,[17][18][19].…”

Diversification and colonization processes in Gobioidei predicted based on mitochondrial 12S rRNA with focusing on Oxudercidae

“…Gobioidei (Gobiiformes) is one of the largest vertebrate taxa with over 2000 species (Nelson 2006). Gobioidei species of this suborder appear in all types of aquatic environments around the globe except Arctic and Antarctic regions (Nelson 2006), and is currently classified into nine families based on the morphological and molecular traits (Thacker 2009;Agorreta et al 2013;Reichenbacher et al 2020). The largest group in Gobioidei is gobies that had been classified as Gobiidae until recently (Nelson 2006;Nelson et al 2016).…”

“… 2013 ; Reichenbacher et al. 2020 ). The largest group in Gobioidei is gobies that had been classified as Gobiidae until recently (Nelson 2006 ; Nelson et al.…”