Ariopsis guatemalensis ( Günther, 1864 ), Gunther, 1864

Marceniuk, Alexandre P., Acero, Arturo, Cooke, Richard & Betancur-R, Ricardo, 2017, Taxonomic revision of the New World genus Ariopsis Gill (Siluriformes: Ariidae), with description of two new species, Zootaxa 4290 (1), pp. 1-42 : 22-27

Ariopsis guatemalensis ( Günther, 1864)

Blue sea catfish (English)

Cominata azulada, Bagre cuatete (Spanish) Figure 14 and 15 , Tables 2–4 and 9.

Arius guatemalensis Günther, 1864:145 . Type locality: Guatemala. Syntypes: BMNH 1853.1 .11.6 (1).

Arius caerulescens Günther, 1864:149 . Type locality: Huamuchal , Guatemala. Syntypes: BMNH 1864.1.26.208–209 (2).

Galeichthys azureus Jordan & Williams, 1895:398, Pl. 27. Type locality: Estuary at Mazatlán , Sinaloa, western Mexico. Holotype: CAS –SU 11575.

Galeichthys guatemalensis, Regan, 1906 –1908: 123; Meek & Hildebrand, 1923: 110.

Arius guatemalensis, Kailola & Bussing, 1995 ;

Ariopsis guatemalensis, Castro-Aguirre, 1999 .

Material examined. Type specimen: BMNH 1853.1 .11.6 (1 male, 249 mm SL), Guatemala . Syntypes of Arius caerulescens : BMNH 1864.1.26.208–209 (2, 218 and 258 mm SL), Guatemala, Huamuchal (=Guamuchal). Nontype specimens: STRI 15941 (1, 255 mm SL), El Salvador, fish market ; UMMZ 178475 (2, 152– 212 mm SL), Mexico, Guerrero, Laguna de Coyuca, ca 10 mi NW of Acapulco , 3 mi NW of military airport on SW side of the Laguna; UA 67–138–1 (1), Mexico, Nayarit, beach at San Blas; UA 70–24–4 (1), Mexico, Oaxaca, Laguna Pto Escondido.

Diagnosis. Ariopsis guatemalensis is distinguished from all other congeners by mesethmoid median portion wide (vs. narrow, Fig. 3 ), medial notch of mesethmoid large and shallow (vs. narrow and deep, Fig. 3 ). The species can be further differentiated as follows: from A. assimilis , from Mexico (Quintana Roo) to Honduras (Caribbean), by its wider mouth, 13.0–15.2% SL (vs. 10.5–12.9% SL), wider cephalic shield at frontal area, 10.0–11.5% SL (vs. 8.8–10.1% SL); from A. felis , from Massachusetts ( US) to Yucatán in Mexico (Caribbean), by its wider distance between anterior nostrils, 7.1–8.6% SL (vs. 4.6–6.4% SL), wider distance between posterior nostrils 7.2–8.7% SL (vs. 4.2–7.1% SL), osseous medial groove absent (vs. present; Figs. 3 and 15 ), fleshy medial groove of neurocranium conspicuous or inconspicuous, but never surpassing posterior margin of eyes (vs. conspicuous and very long, always surpassing the posterior margin of eyes, Figs. 4 and 15 ), lateral margin of sphenotic straight, as wide medially as anteriorly (vs. notching, at middle portion narrower that anterior portion, Figs. 3 and 15 ), pterotic lateral margin markedly convex, sometimes angled (vs. smoothly convex, Figs. 3 and 15 ); from A. gilberti , from Mexico (EP), by 31–39 gill rakers on the first and second gill arches (vs. 40–42), wider distance between anterior nostrils 7.1–8.6% SL (vs. 5.5–6.5% SL), wider distance between posterior nostrils 7.2–8.7% SL (vs. 4.9–6.7% SL), wider cephalic shield at frontal area 10.0–11.5% SL (vs. 8.3–9.8% SL), wider cephalic shield at lateral ethmoid area 14.3–15.3% SL (vs. 12.5–14.0% SL), osseous medial groove absent (vs. present; Figs. 3 and 15 ), fleshy medial groove of neurocranium conspicuous or inconspicuous, but never surpassing posterior margin of eyes (vs. conspicuous and very long, always surpassing the posterior margin of eyes, Figs. 4 and 15 ), lateral margin of sphenotic straight, as wide medially as anteriorly (vs. notched, narrower medially than anteriorly, Figs. 3 and 15 ); from A. jimenezi , from Archipiélago de Las Perlas in Panama (EP), by its wider distance between anterior nostrils 7.1–8.6% SL (vs. 5.6–6.5% SL), longer pectoral spine 18.2–20.5% SL (vs. 14.6–18.1% SL), osseous medial groove absent (vs. present; Figs. 3 and 15 ), fleshy medial groove of neurocranium conspicuous or inconspicuous, but never surpassing posterior margin of eyes (vs. conspicuous and very long, always surpassing the posterior margin of eyes, Figs. 4 and 15 ), lateral margin of sphenotic straight, as wide medially as anteriorly (vs. notched, narrower medially than anteriorly, Figs. 3 and 15 ), external posterior branch of lateral ethmoid colunar and thin (vs. depressed and thick, Fig. 3 ), fenestra delimited by mesethmoid and lateral ethmoid conspicuous (vs. inconspicuous, Fig. 3 ); from A. seemanni , from El Salvador to Panama (EP), by the absence of osseous medial groove delete (vs. present; Figs. 3 and 15 ), lateral margin of sphenotic straight, as wide medially as anteriorly (vs. notched, narrower medially than anteriorly, Figs. 3 and 15 ); from A. simonsi , from Colombia to Peru (EP), by the absence of an osseous medial groove (vs. present; Figs. 3 and 15 ).

Description. Morphometrics and meristics summarized in Tables 2–4, 9. Head moderately long, wide and high, especially depressed at lateral ethmoid and frontal area, profile slightly elevated posteriorly, straight from mesethmoid to parietosupraoccipital. Snout rounded and moderately long. Anterior nostril rounded, with fleshy edge, posterior nostril covered by flap of skin; nostrils moderately separated relatively near to orbit, not connected by fleshy furrow. Eye lateral, relatively small; eyes well separated. Three pairs of long teretiform barbels; maxillary barbel surpassing or not membranous portion of operculum, lateral and mesial mental barbel not reaching posterior margin of gill membrane. Osseous bridge formed by lateral ethmoid and frontal moderately long and slender, delimiting a fenestra little evident under the skin. Cephalic shield exposed, moderately long and relatively narrow on supracleithrum area, and wider on lateral ethmoid and frontal areas, with thick granulation, forming distinct patterns from eyes to parietosupraoccipital procces. Fleshy portion of dorsomedial groove of neurocranium, affixed to anterior cranial fontanel, short, conspicuous or inconspicuous, and not reaching eyes. Lateral margin of sphenotic straight, as wide medially as anteriorly. Pterotic lateral margin markedly convex, sometimes angled. Parietosupraoccipital keeled, triangular, with straight lateral margins converging posteriorly, relatively long and moderately wide at posterior portion, with posterior margin convex. Nuchal plate crescent-shaped, conspicuously granulated dorsally, moderately long and narrow. Mouth subterminal, very large, with lips moderately thick and lower jaw arched. Vomerine tooth plates rounded. One pair of accessory tooth plates ovate, with sharp teeth. Premaxilla rectangular transversally, long and wide, with sharp teeth. Dentary with eyebrow-shaped patch of teeth, separated at midline with sharp teeth. Gill membranes fused, attached to isthmus. Fourteen to 18 acicular gill rakers on first arch, 16–21 spike-shaped gill rakers on second arch and rakers present on posterior margin of all gill arches.

Body wider than its height at pectoral girdle area, progressively compressed from pectoral to caudal peduncle, ventrally flattened from pectoral girdle to anal origin. Lateral line sloping ventrally on anterior one-third, extending posteriorly to caudal peduncle, bending abruptly onto dorsal lobe of caudal. Dorsal spine relatively short and thick, shorter than pectoral spine; anterior margin granulated on basal two-thirds, with weak serrations on distal third; posterior margin smooth on basal third, distal third with weak serrations. Seven dorsal soft rays. Pectoral spine moderately long and thick; two-thirds of anterior margin weakly granulated, with weak serrations on distal third; posterior margin straight on basal one-fourth, distal three-fourths with weak serrations. Nine to eleven pectoral soft rays. Posterior process of cleithrum triangular smooth to rugose, slightly visible. Pelvic fin deep and large at base, with six rays, and well-developed fleshy protuberances in adult females. Adipose fin low, with base moderately long, shorter than anal base. Anal fin moderately high and long at base, with 16–19 rays and ventral profile convex. Caudal peduncle moderately high. Caudal-fin forked, dorsal and ventral lobes relatively long, dorsal lobe somewhat longer than ventral lobe, slightly pointed.

Maximum length: Grows to 450 mm TL.

Coloration in alcohol. Head and body dark brown to bluish above, whitish below; dorsal surfaces of pelvic proximally black, distally lighter; anal dark, distal tips lighter; caudal grayish to blackish ( Fig. 14 ).

Sexual dimorphism. Only females have well-developed fleshy protuberances or pads in basal portion of pelvics, especially during reproductive season. Vomerine tooth patches and accessory tooth patches not observed directly, but possibly showing same variation described for A. canteri and A. jimenezi .

Distribution and habitat. The EP Ariopsis guatemalensis occurs in estuarine and marine waters, from the mouth of Colorado River (Sonora), Pacific Mexico, to Costa Rica ( Fig. 5 ).

Molecular evidence and phylogenetic relationships. Ariopsis guatemalensis is the sister species of a clade including A. jimenezi , A. simonsi , A. seemanni and A. canteri ( Fig. 9 ).

Remarks. Günther (1864) described Arius guatemalensis based on specimens collected on the Pacific side of Guatemala ( Figs. 14 and 15 ). In recent literature ( Kailola & Bussing, 1995; Ferraris, 2007), two nominal species have been considered junior synonyms of Ariopsis guatemalensis . Arius caerulescens , described by Günther (1864) based on two specimens from Guamuchal (=Huamuchal) in Guatemala, and Galeichthys azureus , described by Jordan & Williams (1895) based on a unique specimen from an estuary at Mazatlán (Sinaloa), western Mexico. There is little conflict in the literature about the taxonomic status of Galeichthys azureus , as junior synonym of A. guatemalensis . Arius caerulescens ( sensu Jordan & Gilbert, 1882; Jordan & Evermann, 1896; Eigenmann & Eigenmann, 1890; Regan, 1906,1908) is accepted as a synonym of A. guatemalensis based on characters recognized in present study as sexually dimorphic (e.g., the vomerine tooth plates continuous with larger clubshaped palatine, vs. oblong or oval, continuous or not, with palatine patches a little larger than vomerine in A. guatemalensis ) or show ontogenetic variation (e.g., maxillary barbel extending to the opercle or near to base of pectoral; vs. extending beyond the base of pectoral in A. guatemalensis ).

Figures

FIGURE 3. Neurocranium, dorsal view. A. Ariopsis guatemalensis, STRI 5.2.13.3.; B. A. felis, catfishesbone. acnatsci. org; C. A. canteri, uncataloged; D. A. seemanni, STRI 5.1.1.19.; E. A. jimenezi, STRI no registry; F. A. simonsi, STRI 5.1. 1.10. Abbreviation: LEepb, external posterior branch of Lateral Ethmoid; PT, Pterotic; MS, Mesethmoid; MSmn, Mesethmoid medial notch; mg, medial groove of cranium; SH, Sphenotic.

FIGURE 4. Medial groove of neurocranium. A. Ariopsis felis and B. A. assimilis. White, anterior fleshy portion (apposed to the anterior cranial fontanel); gray, posterior bony portion (formed by the mesial depression of the frontals and the anterior portion of parietosupraoccipital).

FIGURE 5. Sampling localities of examined material.

FIGURE 9. A, Clade including the genera Sciades + Potamarius + Ariopsis, extracted from the Ariidae tree of Betancur-R. et al. (2012), including five of the eight species of Ariopsis validated herein. The complete time tree was estimated using a Bayesian analysis of five mitochondrial and six nuclear gene fragments and 19 calibration points (both inside and outside Ariidae). B, Rooted RAxML phylogram with expanded specimen sampling for six species of Ariopsis, but based on the analysis of only two mitochondrial genes (Cyt b and ATPase 8 / 6; 1937 bp). Nodal numbers indicate RAxML bootstrap support values and posterior probability values (MrBayes tree), respectively. The RAxML and MrBayes trees are identical with respect to topology and highly similar with respect to branch lengths. Two letter country codes follow ISO- 3166.

FIGURE 14. Body in lateral view. (A) Ariopsis guatemalensis, 260 mm SL, Syntypes, BMNH 1853.1.11.6; (B) Arius caerulescens, Syntypes, BMNH 1864.1.26.208 – 209; (C) Galeichthys azureus, Holotype, CAS-SU 11575.

FIGURE 15. Head in dorsal view. (A) Ariopsis guatemalensis, Syntypes, BMNH 1853.1.11.6; (B) Arius caerulescens, Syntypes, BMNH 1864.1.26.208 – 209; (C) Galeichthys azureus, Holotype, CAS-SU 11575.