Revalidation of the genus Ichthyocoris Bonaparte, 1840 (Actinopterygii: Blenniiformes: Blenniidae)

Combtooth blennies belonging to the genus Salaria were known to have marine and freshwater species. However, recent molecular studies highlighted this genus as paraphyletic, clearly distinguishing both marine and freshwater species. In this paper, we revalidate the genus Ichthyocoris, which corresponds to the freshwater species: Ichthyocoris atlantica (Doadrio, Perea et Yahyaoui, 2011), new combination, Ichthyocoris economidisi (Kottelat, 2004), new combination, and Ichthyocoris fluviatilis (Asso y del Rio, 1801), new combination. It is distinguishable by the presence of brownish bars on the flanks not contrasted with black dots conferring a marble coat, a dorsal fin slightly notched between spined and soft rays (except for I. atlantica), 16–18 dorsal-fin soft rays, 16–20 anal-fin soft rays, 34–38 vertebrae, 8–9 circumorbital pores, 8–11 preopercular pores, and 3 supratemporal pores. The genus Salaria corresponds to the marine species Salaria basilisca (Valenciennes, 1836) and Salaria pavo (Risso, 1810).

In this study, we focused on the genus Salaria Bath [ex Forsskål], 1977(see Fricke 2008 for nomenclature changes in relation to Salaria Forsskål, 1775). This genus, belonging to the Salariinae subfamily and the Parableniini tribe (Hastings and Springer 2009), is characterized by a dorsal fin with XII to XIV spines and 15 to 25 rays, an anal fin with II spines and 18 to 26 rays, pectoral fins with 13 to 15 rays, absent or small supraorbital and nasal tentacles, a lateral line formed by anterious tubes more or less continuous, one row of teeth with one canine on each side of each jaw with 14 to 35 teeth on the upper jaw and 14 to 25 teeth on the lower jaw, a toothed vomer, a wide gill opening, a gill membrane not joined with isthmus and a sexual dimorphism, with the presence of a crest on the male's head (Norman 1943;Bath 1977Bath , 2001Krupp and Schneider 1989;Gharred and Ktari 2001;Orlando-Bonaca and Lipej 2010). It includes five species, two marine and three freshwater: Salaria basilisca (Valenciennes, 1836) occurring in the Mediterranean Sea, Salaria pavo (Risso, 1810) found in the eastern Atlantic (Bay of Biscay, Iberic coast) and the Mediterranean Sea (Almada et al. 2001), Salaria fluviatilis (Asso y del Rio, 1801) occurring in coastal catchments of the Mediterranean basin and the Atlantic Guadiana drainage in Spain (Perdices et al. 2000;Kottelat and Freyhof 2007), Salaria economidisi Kottelat, 2004 which is endemic to the lake Trichonis in Greece (Kottelat 2004), and Salaria atlantica Doadrio, Perea et Yahyaoui, 2011 which is endemic to the Sebou drainage in Morocco (Doadrio et al. 2011). All these species are distinguishable according to morphology, molecular and ecology data, as well as color patterning (Perdices et al. 2000;Kottelat 2004;Almada et al. 2009;Orlando-Bonaca and Lipej 2010;Doadrio et al. 2011;Geiger et al. 2014;Belaiba et al. 2019;Vecchioni et al. 2019;Tiralongo 2020;Wagner et al. 2021). Nuclear markers also highlighted that the two marine species S. basilisca and S. pavo can hybridize .
The genus Salaria has also a complex taxonomic history: these blennies species belonged first to the genus Blennius Linnaeus, 1758 (see Bath 1973) or as a Salaria subgenus (Norman 1943), which was later split into several genera by Bath (1977), thus revalidating Salaria. Using morphological data, Bock and Zander (1986) included Salaria within the genus Lipophrys Gill, 1896. Finally, molecular data strongly support the validity of the genus Salaria (see Almada et al. 2005Almada et al. , 2009Wagner et al. 2021). However, both marine and freshwater species are well discriminated with a common ancestor estimated at the Miocene (around 35-5 Ma according to studies of Almada et al. 2009;Wagner et al. 2021). Moreover, this genus seems to be paraphyletic according to mitochondrial and nuclear markers (Hundt et al. 2014;Vecchioni et al. 2019Vecchioni et al. , 2022.
The type species of the genus Salaria Bath [ex Forsskål], 1977, designated by Fricke (2008, is Gadus salaria Walbaum [ex Forsskål], 1792 and is a nomen oblitum synonym of Salaria basilisca. So, the genus Salaria corresponds to the marine clade. Bonaparte (1840) described the genus Ichthyocoris corresponding to freshwater blennies. Its type species, designated by Jordan (1919), is Salarias varus Risso, 1827 which is a junior synonym of Salaria fluviatilis (see Fricke et al. 2007). Ichthyocoris is currently considered as a nomen oblitum synonym of Salaria Bath [ex Forsskål], 1977(see Fricke 2008. The generic concept is widely discussed by Dubois (1982Dubois ( , 1988aDubois ( , 1988b. According to him, a genus is considered as monophyletic, a genetic unit with the possibility of hybridization between species, and an ecological unit as genera occupy defined adaptative zones. Marine and freshwater Salaria fill these conditions, even if no hybridization between freshwater species was highlighted due to the absence of sympatry. According to Freyhof and Yoğurtçuoğlu (2020), a genus should be also diagnosable morphologically. In this paper, we bring a morphological diagnosis in order to validate the genus Ichthyocoris following an integrative taxonomy approach (e.g., Padial et al. 2010;Schlick-Steiner et al. 2010).

Material and methods
In order to distinguish genera, we did a bibliographical review of diagnoses published (Wirtz 1976;Bath 1977;Papaconstantinou 1977aPapaconstantinou , 1977bGharred and Ktari 2001;Kottelat 2004;Kottelat and Freyhof 2007;Doadrio et al. 2011;Kara and Quignard 2018;Keith et al. 2020) as well as the original descriptions of both genera Salaria and Ichthyocoris (see Bonaparte 1840;Bath 1977) and their type species respectively Gadus salaria and Salarias varus (see Walbaum 1792; Risso 1827). Color patterning characterization follows Orlando-Bonaca and Lipej (2010). We used available pictures on GBIF and Kottelat (2004) as well as our own pictures to characterize color patterning. X-ray pictures were also taken on specimens in collections. Notation for dorsal and anal-fin rays' counts follows Hubbs and Lagler (1947). The following characters were examined: color patterning, dorsal-fin rays, anal-fin soft rays, pectoral-fin rays, pelvic-fin rays, number of teeth on each jaw, number of vertebrae, the form of the supraopercular tentacle.  Bath (1977).
Distribution. Ichthyocoris is present in drainages of the Mediterranean basin, in catchments of the Atlantic coast in Morocco and Spain as well as in the Black Sea.
Remarks. Comparing our diagnosis with the description of Salarias varus from Risso (1827), the three species do belong to the genus Ichthyocoris: the presence of dark dots on the body, 29 dorsal-fin spined and soft rays, and 19 anal-fin spined and soft rays. In the same fashion, comparing characters of S. basilisca and S. pavo with the diagnosis of Gadus salaria from Walbaum (1792), both species belong to the genus Salaria: the presence of 36 dorsal-fin spined and soft rays and 26 anal-fin spined and soft rays.
Other characters may discriminate between both genera: Papaconstantinou (1977a) distinguished I. fluviatilis from S. basilisca and S. pavo by the two lateral ethmoid bones between the median ethmoid and the vomer (vs. median ethmoid connected to the vomer). However, this character state is shared by other blenniids and needs to be checked within the two other Ichthyocoris species. Similarly, karyotype studies pointed out differences between I. fluviatilis and S. pavo (heterochromatin concentrated on the entire arm of two chromosome pairs like Lipophrys spp., vs. homogeneous distribution of heterochromatin like Parablennius spp. (Cataudella and Civitelli 1975;Unal et al. 2016). This character needs to be explored as well to characterize both Ichthyocoris and Salaria genera.
In a recent study, Vecchioni et al. (2022) also split the genus Salaria, distinguishing marine Salaria spp. from    (Bath 1977;Kottelat 2004;Doadrio et al. 2011;Tiralongo 2020). Their diagnosis is similar to ours for Ichthyocoris for these two characters. Thus, Salariopsis and Ichthyocoris designate the same taxa. However, the nomen Ichthyocoris Bonaparte, 1840 is older than Salariopsis Vecchioni, Ching, Marrone, Arculeo, Hundt et Simons, 2022. Thus, the principle of priority must be applied (art. 23.1 ICZN): Ichthyocoris must be the valid nomen and Salariopsis, its junior synonym. Kottelat (2004) suspects a population from Lake Kinneret (Israel) to belong to a distinct species. Molecular studies confirm that populations of the Eastern Mediterranean basin form a distinct evolutionary lineage (Doadrio et al. 2011;Geiger et al. 2014;Belaiba et al. 2019;Wagner et al. 2021). Another evolutionary lineage in the Guadiana catchment of the Atlantic basin from Spain was also highlighted with molecular data (Perdices et al. 2000;Almada et al. 2009;Doadrio et al. 2011;Méndez et al. 2019;Wagner et al. 2021). These two evolutionary lineages may correspond to two new Ichthyocoris species if morphological characters were to be found.