Cathorops mapale, Ricardo Betancur-R. & Arturo Acero P., 2005

Ricardo Betancur-R. & Arturo Acero P., 2005, Description of Cathorops mapale, a new species of sea catfish (Siluriformes: Ariidae) from the Colombian Caribbean, based on morphological and mitochondrial evidence., Zootaxa 1045, pp. 45-60 : 47-58

Cathorops mapale new species

Figs. 1-2

Arius spixii (non Agassiz); Dahl (1971): 49-50.

Cathorops spixii (non Agassiz); Taylor and Menezes (1978); Galvis (1983): 108-146; Santos-Martinez and Acero (1991): 254; Cervigón et al. (1992): 260 (in part); Grijalba-Bendeck (1998); Tíjaro et al. (1998): 87-102; Rueda (2001): 217-226; Acero (2002): 849 (in part); Marceniuk and Ferraris (2003): 449-450 (in part).

Cathorops sp.9 ; Marceniuk (1997): 127-134; Betancur-R. et al. (2004).

Cathorops sp.12 ; Marceniuk (1997): 135-142 (in part).

Holotype. INVEMAR-PEC 5333 (stri x3600), female, 183.5 mm SL, May 2003, Ciénaga Grande de Santa Marta (CGSM), Magdalena, CO (10°59’ N, 74°17’ W). Cyt b, ATPase 8 and ATPase 6 sequences are available in GenBank, accession numbers AY575016, AY575018 and AY575021, respectively.

Paratypes. ICN-MHN 8244, female, 166 mm SL, December 2003, CGSM, Magdalena, CO (10°59’ N, 74°17’ W) ; INVEMAR-PEC 277, female, 256 mm SL, March 1988, Tasajera, Magdalena, CO (11°0’ N, 74°20’ W) ; INVEMAR-PEC 1584, male, 166 mm SL, October 1988, Costa Verde, CGSM, Magdalena, CO (11°02’ N, 74°15’ W) ; ICN-MHN 8245, one female and one male, 196-164 mm SL , INVEMAR-PEC 5730, female, 157 mm SL , INVEMAR-PEC 5733, 14 males and 12 females cleared and stained, 110-144 mm SL, February 1998, 20 m depth, Golfo de Salamanca, Magdalena, CO (11°6’ N, 74°18’ 19’ W) ; INVEMAR-PEC 3654, female, 180 mm SL, August 2001, Ciénaga de Soledad, Cór-, CO (9°20’ N, 75°52’ W) ; INVEMAR-PEC 5197, female, 156 mm SL, August 1995, mouth of Río Tinajones, Córdoba, CO (9°25’ N, 75°48’ W) ; ICN-MHN 8246, one female and one male, 165-179 mm SL, January 2004, mouth of Río Sinú, Córdoba, CO (9°26’ N, 75°55’ W) ; INVEMAR-PEC 5501, one female and one male, 151-152 mm SL, January 2003, 20 m depth, Golfo de Urabá, Antioquia, CO (8°29’ N, 77°13’ W) ; INVEMAR-PEC 5732, male, 157 mm SL, February 2003, 10 m depth, Golfo de Urabá, Antioquia, CO (7°56’ N, 76°53’ W) ; INVEMAR-PEC 5731, two females, 139-172 mm SL, February 2003, 10 m depth, Golfo de Urabá, Antioquia, CO (8°17’ N, 76°48’ W) ; INVEMAR-PEC 5348 (stri x3601), female, 118 mm SL, June 2003, Río Atrato, mouth El Roto, Golfo de Urabá, Antioquia, CO (76°58’W, 8°07' N), Cyt b, ATPase 8 and ATPase 6 sequences are available in GenBank, accession numbers AY575017, AY575019 and AY575020, respectively ; ICN-MHN 8247, female, 143 mm SL, January 2004, Río Atrato, mouth El Roto, Golfo de Urabá, Antioquia, CO (76°58’W, 8°07' N) .

Diagnosis. Cathorops mapale is distinguished from other Cathorops species inhabiting the western Atlantic by the following combination of features: anterior gill rakers on first gill arch 6-8+14-16 (20-24, mode 23), anterior gill rakers on second gill arch 5-6+13-15 (18-21, mode 20); maxillary barbels 27.8-39.3% (mean 32.3%) SL; medial head groove long and deep, extending posteriorly almost to supraoccipital keel (Fig. 2). The species is also distinguished from the C. fuerthii species group, its sister clade from the eastern Pacific, by having higher anterior gill raker counts on first (14-15 in the C. fuerthii group) and second (15-16 in the C. fuerthii group) gill arches and by having a smaller mouth (8.3-10.6% SL in C. mapale and 11.0-11.6% SL in the C. fuerthii group). Meristic and morphometric data of the type series are summarized in Table 1.

Description (based on combined data from type series). Body depth 4.5-5.9 in SL, slightly deeper in females than in males; body width 4.9-5.9 in SL, slightly wider in females than in males. Head moderately depressed, posterior profile slightly convex; depth 5.5-6.6 in SL and 1.4-2.0 in HL; length 3.3-4.2 in SL, slightly longer in males than in females. Snout rounded in transverse section, length 3.1-4.3 in HL. Mouth width 2.5- 3.2 in HL. Lips thin to moderate, upper lip width 16.2-46.0 in HL. Maxillary barbels 0.6- 1.0 in HL and 2.5-3.6 in SL, reaching beyond pectoral fin bases; mandibulary barbels 0.9- 1.5 in HL and 3.8-5.3 in SL, passing gill membrane; mental barbels 1.4-2.2 in HL and 5.6-7.7 in SL, not reaching gill membrane. Distance between anterior nostrils 5.3-7.3 in HL; distance between posterior nostrils 4.2-6.0 in HL; fleshy furrow between posterior nostrils absent. Eyes lateral; diameter 19.3-26.9 in SL, 4.6-7.3 in HL, and 2.1-3.5 in interorbital distance. Interorbital distance 7.3-9.4 in SL and 1.9-2.6 in HL. Postorbital length 1.6-2.0 in HL, slightly longer in males than in females. Head shield exposed, covered posteriorly with scattered granules, extending anteriorly to opposite eyes; coarse to sharp bony spines on its anterior surface absent. Bony ridges formed by frontals and lateral ethmoids sharp and evident on the skin. Supraoccipital process keeled and slightly convex; length 8.2-9.8 in SL and 1.9-2.8 in HL; posterior width 30.6-44.8 in SL, 7.7-11.5 in HL, and 3.4-4.8 in its length. Predorsal plate narrow and crescent-shaped, width 3.3-4.5 in HL, length 4.7-6.7 in HL. Dentary teeth villiform, relatively coarse, and molariform. Palatine teeth molariform, arranged in two elliptical patches; patches larger and with higher tooth counts in females (46-84) than in males (33-48). Vomerine tooth patches absent. Gill rakers well developed and uniformly distributed along rear surfaces of all gill arches. Predorsal fin length 2.6-3.0 in SL. Dorsal-fin base 9.4-11.2 in SL; dorsal-fin spine thick and long, its anterior margin slightly granular, its posterior margin almost totally serrated, longer than pectoral-fin spine, height 3.8-5.3 in SL. Distance between dorsal fin and adipose fin 3.1-4.0 in SL. Base of adipose fin 9.6-18.5 in SL; height of adipose 7.8-13.1 in SL. Prepectoral fin length 4.1-5.0 in SL. Pectoral-fin base 19.2-25.4 in SL; pectoral-fin spine wide and long, its anterior margin granular, its posterior margin serrated, length 5.2- 5.8 in SL. Prepelvic fin length 1.9-2.2 in SL. Pelvic-fin base 22.2-33.1 in SL, slightly larger in females than in males; pelvic-fin length 5.4-7.0 in SL in females and 7.1-8.1 in males. Anal-fin base 4.9-6.4 in SL, slightly larger in females than in males; anal-fin height 4.6-6.1 in SL, slightly higher in females than in males. Caudal peduncle depth 12.2-14.5 in SL, slightly deeper in females than in males. Caudal fin deeply forked, its lower lobe shorter than upper lobe. Dorsal-fin elements I,7; pectoral-fin elements I,10-11; pelvic-fin elements 6; anal-fin elements 21-25; ribs 10-13, postweberian vertebrae: 10 precaudal and 34 caudal (two females and two males).

Coloration. In alcohol, dark gray to brown on dorsum, silvery to white below. Individuals living in freshwaters are said to have dark golden cast (Galvis, 1983).

Size. Largest specimen examined 256 mm SL and 306 mm TL (INVEMAR-PEC 277, paratype). The maximum length reported by Galvis (1983) in the CGSM is 31 cm TL.

Etymology. The specific epithet mapale refers to the common name (chivo mapalé) given to the species by artisanal fishers in most Colombian localities. This is also the name of a Colombian rhythm of African origin typical of the fishery community of the Colombian Caribbean. The specific name should be treated as a noun in apposition.

Common names. We propose the official English common name of Mapalé Sea Catfish for Cathorops mapale . To fulfill the need of official names in other languages, we also propose chivo mapalé (Spanish) and mâchoiron mapalé (French).

Habitat and distribution. The examined material of C. mapale comes from the central and southwestern coasts of the Colombian Caribbean, including CGSM and its surrounding marine waters, mouth of Río Sinú, and the Golfo de Urabá (Fig. 3). The species seems to be endemic to Colombia, and it inhabits fresh and brackish waters in coastal lagoons and near-shore marine waters. Examined paratypes from Golfo de Salamanca and INVE- MAR-PEC 5501 from Golfo de Urabá were collected at 20 m depth.

Discussion

Cathorops spixii was described by Agassiz in Spix and Agassiz (1829) from equatorial Brazil; however, the original description is unclear and apparently no type material was designated. The name spixii has been employed to include other species of the genus Cathorops with uncertain status that occur in the western and southwestern Caribbean Sea and even in the southern Gulf of Mexico. This confusion can be traced back at least to Dahl (1971) and Taylor and Menezes (1978), who extended the species’ distribution to Colombia and to the eastern coast of Middle America, respectively. Marceniuk (1997), in his unpublished M.Sc. thesis, presented a taxonomic revision of Cathorops species from both American coasts, using morphometry and multivariate statistics. He stated that C. spixii is a valid species, but restricted its distribution to the region from Brazil to the Guianas. Marceniuk (1997) also proposed that in the Caribbean Sea there are three undescribed species, one of which is our Mapalé Sea Catfish (Marceniuk’s Cathorops sp.9 ). We examined material of C. spixii collected by L. Agassiz in Brazil at several latitudes ranging from 1ºS to 22ºS and found morphological differences between that species and C. mapale . The latter can be distinguished from the former by having modally higher anterior gill raker counts on first (23 in C. mapale , 19 in C. spixii ) and second (20 in C. mapale , 18 in C. spixii ) gill arches (see also Table 2).

Cathorops mapale can be differentiated from C. spixii not only by external morphology, but also by taking into account the species’ genealogical histories. Betancur-R. (2003), in his study of the systematics of New World sea catfishes using cyt b and ATPase 8/6 mitochondrial markers, presented a relatively complete phylogenetic hypothesis of at least 11 species of the genus Cathorops (including Arius dasycephalus Guenther ) (Fig. 4). From his hypothesis it is evident that the Mapalé Sea Catfish is more closely related to the C. fuerthii species group from the eastern Pacific (posterior probability support = 1.0; Bootstrap support = 100%) than to the C. spixii / C. cf. arenatus clade from the western Atlantic. Also, the K2 genetic divergence values of the combined mitochondrial genes are lower between C. mapale and the C. fuerthii group (2.21-2.81%) than between C. mapale and the C. spixii / C. cf. arenatus group (5.88-6.22%) (Betancur-R., 2003). The genetic divergences found within the transisthmian C. mapale / C. fuerthii clade are close to those found in other sister-species of fishes implicated in vicariant speciation due to the Pliocenic rising of the Panamá isthmus (see Bermingham et al., 1997). Alternatively, it might be possible to accept a single transisthmian species of Cathorops , comprising the C. fuerthii group and C. mapale . Nevertheless, because C. mapale is unambiguously separated from C. fuerthii by external characters (see diagnosis and Table 2), such a hypothesis is supported neither by morphology nor by the relatively high genetic distances between lineages (see other K2 divergence values within sister-species of Cathorops in Table 3). The Mapalé Sea Catfish is also separated from other congeners by 8.09-13.37% combined K2 sequence divergence (see details in Table 3).

Marceniuk (1997) reported Cathorops sp.9 from the central and northeastern coasts of Colombia ( Ciénaga de la Virgen and CGSM) and western Venezuela (lago de Maracaibo). He also reported another undescribed Caribbean species (Marceniuk’s Cathorops sp.12 ) occurring from Río Sinú and Golfo de Urabá, Colombia, to Honduras. Because part of the material of C. mapale that we examined was collected at the mouth of Río Sinú and Golfo de Urabá (Fig. 3), southwest of the locations reported by Marceniuk (1997) for his Cathorops sp.9 , it would correspond to Marceniuk´s (1997) Cathorops sp.12 . After comparing topotype material of C. mapale from CGSM and surrounding marine waters with type material from both southwestern locations slight differences are found. The three pairs of barbels and the eye tend to be smaller in topotype material (Table 1); however, those differences could be reflecting allometry, because CGSM material examined is larger (157-256 mm SL) than southwestern material (118-180 mm SL). Nevertheless, even if the differences are consistent after examining additional material, we conclude that they are only valid at the population level. This hypothesis is also confirmed by the mitochondrial genetic divergence values. In Table 3 are presented K2 genetic distances among several sister-species pairs within the genus Cathorops (see clades in Fig. 4) from the three loci sequenced by Betancur-R. (2003). The combined mitochondrial divergence value between the holotype and a Golfo de Urabá paratype (INVEMAR-PEC 5348) seems too small (0.62%) to represent specific differentiation. Such a value corresponds to less than half of those observed in the closest sister species pairs of Cathorops studied by Betancur-R. (2003), C. spixii and C. cf. arenatus , with 1.46-1.68% combined K2 distances. However, it is possible that Marceniuk´s (1997) Cathorops sp.12 is a valid species different from C. mapale . If so, the species probably occurs farther north in the Caribbean Sea. The distribution given for Cathorops sp.12 by Marceniuk (1997) is also rejected in the light of the distributional pattern revealed by other ariids inhabiting in the southern Caribbean, which western limit is the Golfo de Urabá [e.g. New Granada Sea Catfish ( Ariopsis sp.), Notarius neogranatensis (Acero and Betancur-R.) , Bagre bagre (Linnaeus) , Sciades proops Valenciennes ].

Another undetermined species of Cathorops occurs along the northeastern coast of Colombia (Guajira) (Fig. 3). This species can be easily separated from the Mapalé Sea Catfish by having modally lower anterior gill raker counts on first (19 in Cathorops sp., 23 in C. mapale ) and second (18-19 Cathorops sp., 20 in C. mapale ) gill arches and shorter maxillary (21.8-26.0% SL, mean 23.9, in Cathorops sp.; 27.8-39.3% SL, mean 32.3, in C. mapale ), mandibulary (15.9-19.4% SL, mean 17.2, in Cathorops sp; 18.7-26.4% SL, mean 22.4, in C. mapale ), and mental (11.1-13.5% SL, mean 12.4, in Cathorops sp.; 13.0- 17.8% SL, mean 15.1, in C. mapale ) barbels (see also Table 2). Due to the apparent absence of C. mapale along the northeastern coast of Colombia, its presence in western Venezuela, as reported by Marceniuk (1997), needs confirmation. Further studies should include material of Cathorops species from Venezuela and the Guianas in order to establish the identity of Cathorops sp.

Other Cathorops species described from the western Atlantic, such as Arius fissus Valenciennes , A. pleurops Boulenger , Tachisurus agassizii Eigenmann and Eigenmann , and the inquirendae (see Marceniuk and Ferraris, 2003) A. laticeps Guenther , A. nuchalis Guenther , A. puncticulatus Valenciennes , and A. variolosus Valenciennes , were not examined in this work. Nevertheless, the type localities of all of them are between Guyana and Argentina. Because the northeastern distributional limit of C. mapale seems to be the CGSM in the Colombian Caribbean, more than 2500 km of coastline away from Guyana, it is most unlikely that C. mapale is conspecific with any of those species. Material from two putative new species of Cathorops reported from the Centro American Caribbean [ Cathorops sp.10 / Cathorops sp. from the coast of Belize (Marceniuk, 1997; Greenfield and Thomerson, 1997), and Cathorops sp.12 (Marceniuk, 1997)] was neither examined. Comparisons of select features distinguishing C. mapale from five western Atlantic and one eastern Pacific species of Cathorops are summarized in Table 2.

Several Colombian authors have gathered a considerable amount of biological and fishery information about the Mapalé Sea Catfish. Galvis (1983) reported that it spawns throughout the year in the CGSM, with a peak between November and March, and that each female lays 24-30 eggs, which average 9 mm in diameter. He also established that females mature after reaching 20 cm TL and the sex ratio is 4.4 females/male. Grijalba-Bendeck (1998) calculated the biomass of the species to be 141 tons in the CGSM. Following a survey in 1994, Tíjaro et al. (1998) estimated the size of female maturity to be 23 cm and stated that the species is being overfished in the CGSM. INVEMAR (2003) reported that the average size of capture has been below the average size of female maturity between 2000 and 2002 in the CGSM. This information suggests that the Mapalé Sea Catfish is in need of protection, not only due to its restricted distribution, but because it is threatened by overfishing.