Gymnesigobius, Kovačić & Ordines & Ramirez-Amaro & Schliewen, 2019

Kovačić, Marcelo, Ordines, Francesc, Ramirez-Amaro, Sergio & Schliewen, Ulrich K., 2019, Gymnesigobius medits (Teleostei: Gobiidae), a new gobiid genus and species from the western Mediterranean slope bottoms, Zootaxa 4651 (3), pp. 513-530 : 515-519

Gymnesigobius gen. nov.

Diagnosis. (1) chin without fold or barbels; (2) mouth terminal, oblique, with anterior tip above horizontal level of lower eye edge; (3) predorsal area and first dorsal fin base naked; (4) pelvic fin anterior membrane (frenum) well developed; (5) head with anterior oculoscapular ( AOC) and preopercular (PC) canals, with pores σ, λ, κ, ω, α, β, ρ and γ, δ, ε respectively, posterior oculoscapular canal ( POC) absent; (6) pores of head canals enlarged e.g. pores α and ρ larger or about same size as interspaces to pore β; (7) six transverse suborbital rows of sensory papillae, four continuous suborbital rows in front of row b, fifth divided in three parts but in front of row b, sixth just as superior part above row b and below pore α; (8) longitudinal suborbital row b barely reaching forward to the vertical from posterior edge of eye.

This short diagnosis is the combination of the selected cardinal characters that distinguish this new genus from twenty genera presently assigned to the “ Gobius -lineage” sensu Agorreta et al. (2013) (see Genetics and phylogeny results). The combination of eight characters provides differences of three to seven selected characters for each genus (only the characters which are not variable among species in the compared genus and therefore are different between the new genus and all species of the compared genus were counted as different) of the “ Gobius -lineage” sensu Agorreta et al. (2013) ( Table 2 ). Sufflogobius Smith 1956 , for which published morphological data are scarce, also has three different characters (1–3) versus the new genus in this diagnosis, while the state of characters (4–8) is unknown for this genus. Character (1) distinguishes the new genus from Sufflogobius and Benthophilus Eichwald 1831 . Character (2) distinguishes the new genus from all genera except Benthophilus in part, Chromogobius de Buen 1930 in part and Vanneaugobius Brownell 1978 in part, character (3) distinguishes the new genus from all genera except Benthophilus , Corcyrogobius Miller 1972 in part, Coryogalops Smith 1958 in part and Thorogobius Miller 1969 in part. Character (4) is diagnostic only with regard to closely related Odondebuenia de Buen 1930 , Vanneaugobius and Wheelerigobius Miller 1981 . The combination of head canals of character (5) distinguishes the new genus from all genera except Chromogobius , Didogobius Miller 1966 in part, Millerigobius Bath 1973 , Odondebuenia , Vanneaugobius in part. Character (6) distinguishes the new genus from all genera except Thorogobius in part, i.e. one species, T. rofeni Miller 1988 also has large head canal pores. Character (7) distinguishes the new genus from all genera except Coryogalops and Didogobius in part, character (8) distinguishes the new genus from all genera except Benthophilus , Chromogobius in part, Coryogalops in part, Didogobius in part, Millerigobius , Vanneaugobius in part.

Description. Body elongate, laterally more compressed towards caudal peduncle. Head of moderate size and depressed. Snout gently oblique, shorter than eye. Anterior nostril long, tubular, without process from rim; posterior nostril short tube. Eyes large, dorsolateral, distinctly elevated above dorsal profile with narrow interorbital space. Mouth terminal, oblique, with anterior tip above horizontal level of lower eye edge. Chin without fold or barbels. Branchiostegal membrane attached along entire lateral margin of isthmus from immediately anterior to pectoral margin. Cranial roof covered by dorsal axial musculature. No spines on preopercle. Pectoral girdle without dermal flaps on anterior edge. Tongue well-developed. Two dorsal fins, first fin with VI spines, not elongated or filamentous, second dorsal- and anal-fin counts moderate (I/11; I/10 respectively in this species). Pectoral-fin ray count moderately low (17 in this species). Pectoral girdle without flaps on anterior edge. Uppermost rays of pectoral fin not free from membrane. Pelvic fins I,5 + 5,I, left and right fin well connected, anterior pelvic membrane (frenum) well-developed and without lateral lobes. Caudal fin rounded, shorter than head length, with 17 segmented and 14 branched rays. Body scaled. Head with cheek and opercle naked. Predorsal area, first dorsal-fin base and prepectoral naked, breast and belly scaled. Low count of scales in lateral series (28 in this species). No intense colors or complex coloration pattern on body (body with gentle yellow orange pattern in this species). Head with anterior oculoscapular and preopercular canals, posterior oculoscapular canal absent. Pores of head canals enlarged e.g. pores α and ρ larger or about same size as interspaces to pore β. Snout with three median preorbital series and lateral series in four parts. Suborbital rows of sensory papillae with row a absent, longitudinal row b barely reaching forward to the vertical from posterior edge of eye and row d well-developed. Six transverse suborbital rows of sensory papillae, four continuous suborbital rows in front of row b, fifth divided in three parts but in front of row b, sixth just as superior part above row b and below pore α. Anterior dorsal transverse row o distant at the dorsal midline from the equivalent row of the other lateral side. Longitudinal row g not reaching anteriorly to transverse row o. Interorbital papillae absent. Vertebral column with 10 precaudal and 18 caudal vertebrae (including urostyl). Pterygiophore fin formula: 3-22110. Two anal-fin pterygiophores before haemal spine of the 1 st caudal vertebra.

Tables

TABLE 2. Comparison of the eight diagnostic characters of Gymnesigobius medits sp. nov. with other genera of the “Gobius-lineage” sensu Agorreta et al. (2013)

Character in	1	2	3	4	5	6	7a	7b	8
diagnosis
Character	Head barbels	Mouth	Predorsal area	V anterior	Head canals	Pore size	Total number	Number of	Longitudinal
		anterior tip	and D1 base	membrane	and pores		of suborbital	continuous	suborbital row b
			squamation				transversal	suborbital
							rows	transversal rows
								anteriorly + divided
								rows posteriorly
								above/below level
								of row b
Gymnesigobius	head without	above level	predorsal area	present	AOC: σ, λ, κ,	large e.g. pores α, β, ρ	6	4+2/1	barely reaching
medits sp. nov.	barbels	of lower	and D1 base		ω, α, β, ρ; POC	larger or about same size			forward to the
		eye edge	naked		absent; PC: γ,	as their interspaces			vertical from
					δ, ε				posterior edge of
									eye
Babka	head without	below level	predorsal	present	AOC: σ, λ,	pores small e.g. pores α,	7	4+3/2	anteriorly ending
	barbels	of lower	area partially		κ, ω, α, β, ρ;	β, ρ clearly smaller than			below eye
		eye edge	scaled and D1		POC: ρ1, ρ2;	their interspaces
			base scaled		PC: γ, δ, ε
Benthophilus	barbels	variable,	predorsal area	present	head canals	pores absent	7 (last can	4+3/2	barely reaching
	present	above or	and D1 base		absent		be as single		forward to the
	on ventral	below level	naked				papilla)		vertical from
	surface of	of lower							posterior edge of
	head	eye edge							eye
Chromogobius	head without	variable,	predorsal	present	AOC: σ, λ, κ,	pores small e.g. pores α,	7 (last as	5+2/1	anteriorly ending
	barbels	above or	area variably		ω, α, β, ρ; POC	β, ρ clearly smaller than	single papilla)		below eye or to
		below level	scaled and D1		absent; PC: γ,	their interspaces			the vertical from
		of lower	base scaled		δ, ε				posterior edge of
		eye edge							eye
Corcyrogobius	head without	below level	predorsal area	present	AOC: σ, one	pores small e.g. pores α,	6 (last as	4+2/0	anteriorly ending
	barbels	of lower	naked and D1		λ/κ or separate,	β, ρ clearly smaller than	single papilla)		below eye
		eye edge	base variably		ω, α, ρ; POC	their interspaces
			scaled		absent; PC
					absent
Coryogalops	head without	below level	predorsal area	present,	AOC: σ, λ,	pores small e.g. pores α,	5 to 7	variable	anteriorly ending
	barbels	of lower	naked and D1	except	κ, ω, α, β, ρ;	β, ρ clearly smaller than			below eye or to
		eye edge	base variably	in C.	POC: ρ1, ρ2;	their interspaces			the vertical from
			scaled	anomolus	PC: γ, δ, ε				posterior edge of
									eye

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