Ariopsis assimilis ( Günther, 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: 4-8

publication ID

https://doi.org/10.11646/zootaxa.4290.1.1

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http://treatment.plazi.org/id/03992C13-FFBA-FFE6-A1E1-FD491A2FFF3E

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scientific name

Ariopsis assimilis ( Günther, 1864 )
status

 

Ariopsis assimilis ( Günther, 1864) 

Mayan Sea Catfish (English), Bagre maya (Spanish). Figures 1View FIGURE 1 and 2, Tables 2–5

Arius assimilis Günther, 1864:146  . Type locality: Lake Izabal [Yzabal], Guatemala. Holotype: BMNH 1864.1.26.98. Galeichthys assimilis, Regan, 1906  –1908: 122. 

Ariopsis assimilis, Taylor & Menezes, 1978  ; Castro Aguirre et al., 1999: 156–157; Acero P., 2003: 838; Robertson et al., 2015.

Material examined. Type-specimen: BMNH 1864.1.26.98 (female, 290 mm SL), Guatemala, Izabal  . Non-type specimens: USNMAbout USNM 212131View Materials (1, 207 mm SL), Mexico, Quintana Roo  ; UMMZAbout UMMZ 196479View Materials (4, 252– 233 mm SL), Mexico, Quintana Roo, Laguna Bacalar   ; UMMZAbout UMMZ 213491View Materials (2, 168– 225 mm SL), Mexico, Quintana Roo, Laguna Bacalar   ; FMNHAbout FMNH 103770View Materials (2, 243– 254 mm SL), Belize, Belizean Beach , 4.5 miles on western highway  ; AMNHAbout AMNH 35070View Materials (7, 147– 236 mm SL), Guatemala, Izabal, Río Nimblaja, 1 km above mouth into Río Sarstún   ; USNMAbout USNM 114587View Materials (1, 196 mm SL), Guatemala, Río Sarstún , +/- 20 mi. above mouth  ; UMMZAbout UMMZ 197214View Materials (5, 144– 200 mm SL), Guatemala, Izabal, Río Nimblaja, 1 km above mouth in Río Sarstún   ; AMNHAbout AMNH 32941View Materials (2, 194– 245 mm SL), Guatemala, Izabal, Río Dulce, inside channel ca. 400 m, below Castillo San Felipe ; UA 69–91 (1), Mexico, Quintana Roo, Isla Cozumel. 

Diagnosis. Ariopsis assimilis  is distinguished from its congeners as follows: from A. canteri  , from Colombian Caribbean, by 31–36 gill rakers on the first and second gill arches, rarely 37 (vs. 38–44, rarely 36 or 37); from A. felis  , from Massachusetts ( US) to Yucatán in Mexico (Caribbean), by 34–37 gill rakers on the first and second gill arches (vs. 29–32), osseous medial groove absent (vs. present; Figs. 2 and 3View FIGURE 3), fleshy medial groove of neurocranium conspicuous or inconspicuous, but never surpassing posterior margin of eyes (vs. conspicuous and very long, surpassing the posterior margin of eyes, Figs. 2 and 4View FIGURE 4), lateral margin of sphenotic straight, as wide anteriorly as medially (vs. notched laterally, narrower medially than anteriorly, Figs. 2 and 3View FIGURE 3), pterotic lateral margin markedly convex, sometimes angled (vs. smoothly convex, Figs. 2 and 3View FIGURE 3); from A. gilberti  , from Mexico (EP), by the presence of 14–18 gill rakers on the first gill arch (vs. 19–20, Table 3), osseous medial groove absent (vs. present; Figs. 2 and 3View FIGURE 3), fleshy medial groove of neurocranium conspicuous or inconspicuous, but never surpassing posterior margin of eyes (vs. conspicuous and very long, surpassing the posterior margin of eyes, Figs. 2 and 4View FIGURE 4), lateral margin of sphenotic straight, as wide anteriorly as medially (vs. notched laterally, narrower medially than anteriorly, Figs. 2 and 3View FIGURE 3); from A. guatemalensis  , from Mexico to Costa Rica (EP), by its narrower mouth 10.5–13.2% SL (vs. 13.0–15.2% SL, rarely less than 13.2%), narrower cephalic shield at frontals area 8.8–10.1% SL (vs. 10.0–11.5% SL, rarely less than 10.1%), narrow mesethmoid median portion (vs. wide, Fig. 3View FIGURE 3), mesethmoid medial notch narrow and deep (vs. large and shallow, Fig. 3View FIGURE 3); from A. jimenezi  , from Archipiélago de las Perlas in Panama (EP), by longer pectoral-fin spine 18.2–22.6% SL (vs. 14.6–18.1% SL), osseous medial groove absent (vs. present; Figs. 2 and 3View FIGURE 3), fleshy medial groove of neurocranium conspicuous or inconspicuous, but never surpassing posterior margin of eyes (vs. conspicuous and very long, surpassing the posterior margin of eyes, Figs. 2 and 4View FIGURE 4), lateral margin of sphenotic straight, as wide anteriorly as medially (vs. notched laterally, narrower medially than anteriorly, Figs. 2 and 3View FIGURE 3), pterotic lateral margin markedly convex, sometimes angled (vs. smoothly convex, Figs. 2 and 3View FIGURE 3), external posterior branch of lateral ethmoid columnar and thin (vs. depressed and thick, Fig. 3View FIGURE 3), fenestra delimited by mesethmoid and lateral ethmoid conspicuous (vs. inconspicuous, Fig. 3View FIGURE 3); from A. seemanni  , from El Salvador to Panama (EP), by the absence of osseous medial groove (vs. present; Figs. 2 and 3View FIGURE 3), lateral margin of sphenotic straight, as wide anteriorly as medially (vs. notched laterally, narrower medially than anteriorly, Figs. 2 and 3View FIGURE 3); from A. simonsi  , from Colombia to Peru (EP), by the absence of osseous medial groove (vs. present; Figs. 2 and 3View FIGURE 3).

Description. Morphometrics and meristics summarized in Tables 2–5. Head moderately long, wide and relatively low, notably depressed at lateral ethmoid and frontal area, profile elevated posteriorly, straight from mesethmoid to parietosupraoccipital. Snout rounded and moderately long. Anterior nostrils rounded, with fleshy edge, posterior nostril covered by flap of skin; nostrils moderately separated and moderately distant from orbit, not connected by fleshy furrow. Eye lateral, relatively large. Eyes widely spaced. 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 wide on supracleithrum area, and relatively narrow 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, without reaching eyes, posterior osseous medial groove inconspicuous or absent. Lateral margin of sphenotic straight, as wide medially as anteriorly. Pterotic lateral margin markedly convex, sometimes angled. Parietosupraoccipital process keeled, triangular, with straight lateral margins converging posteriorly, relatively short and moderately wide at posterior portion, with posterior margin convex. Nuchal plate crescent-shaped, conspicuously granulated dorsally, moderately long and relatively narrow. Mouth subterminal, moderately 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, moderately 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, 17–20 spike-shaped gill rakers on second arch and some rudiments at the end; rakers present on posterior margin of all gill arches.

13 14 15 16 17 18 19 20

Ariopsis assimilis  1 2 8 2 1

Ariopsis canteri  3 7 1 5 11 Ariopsis felis  2 4 3 1

Ariopsis gilberti  2 3 Ariopsis guatemalensis  1 1 1

Ariopsis jimenezi  3 8 1

Ariopsis seemanni  2 6 1 1

Ariopsis simonsi  1 4 7 3 2

14 15 16 17 18 19 20 21 22 23 24

Ariopsis assimilis  1 4 3 4

Ariopsis canteri  2 5 9 11 5 4 Ariopsis felis  2 5 3

Ariopsis gilberti  1 3 3 1 Ariopsis guatemalensis  1 1 Ariopsis jimenezi  1 1 6 4

Ariopsis seemanni  3 1 3

Ariopsis simonsi  3 1 2 3 3 2 1 1

Body significantly 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-fin 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-fin 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 conspicuous serrations. Nine to 11 pectoral-fin soft rays. Posterior process of cleithrum triangular, slightly visible, smooth to rugose. Pelvic-fin deep and large at base, with six rays, 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 17–20 rays and ventral profile concave. Caudal peduncle moderately high. Caudal-fin forked, dorsal and ventral lobes moderately long, dorsal lobe somewhat longer than ventral lobe, posteriorly slightly pointed.

Maximum length: Grows to 350 mm TL.

Coloration in alcohol. Head and body counter-shaded, dorsum brown to blackish, venter light beige; dorsal surfaces of pelvic and pectorals proximally black, distally lighter; anal dark, distal tips lighter; caudal grayish to blackish ( Fig. 1View FIGURE 1).

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 WA Ariopsis assimilis  occurs in fresh and estuarine waters, from Quintana Roo on the Caribbean coast of Mexico to Honduras ( Fig. 5View FIGURE 5).

Remarks. Ariopsis assimilis  was described by Günther (1864) based on a single specimen collected at Lake Izabal, Guatemala ( Figs. 1View FIGURE 1 and 2). The original description used characters that are shared with congeneric species. Thus, the recognition of A. assimilis  relies on a combination of morphometric, meristic, and osteological features observed on the type specimen and non-type specimens. Posteriorly, Jordan & Gilbert (1882) assigned A. assimilis  to both coasts of tropical America, including Magdalena Bay, Mazatlán, and Altata in Mexico, and the Magdalena River, Colombia. The Colombian Magdalena record is in error, since Jordan & Gilbert (1882) described a fontanel prolonged backward as a narrow groove. After Gunther “ median longitudinal fonticulus on the upper side of the head does not extend to the base of occipital process”, a condition that is verified in the type specimen ( Fig. 2).

USNM

Smithsonian Institution, National Museum of Natural History

UMMZ

University of Michigan, Museum of Zoology

FMNH

Field Museum of Natural History

AMNH

American Museum of Natural History

Kingdom

Animalia

Phylum

Chordata

Class

Actinopterygii

Order

Siluriformes

Family

Ariidae

Genus

Ariopsis

Loc

Ariopsis assimilis ( Günther, 1864 )

Marceniuk, Alexandre P., Acero, Arturo, Cooke, Richard & Betancur-R, Ricardo 2017

2017
Loc

Arius assimilis Günther, 1864 :146

Gunther 1864: 146