Description of Arius neogranatensis, a new species of sea catfish from Colombia, with an identification key for Caribbean ariid fishes

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1 aqua, Journal of Ichthyology and Aquatic Biology Description of Arius neogranatensis, a new species of sea catfish from Colombia, with an identification key for Caribbean ariid fishes Arturo Acero P. 1 and Ricardo Betancur-R. 2 1) Universidad Nacional de Colombia (Instituto de Ciencias Naturales), A.A (INVEMAR), Santa Marta, Colombia. aacero@invemar.org.co. 2) Universidad Nacional de Colombia/INVEMAR, A.A. 1016, Santa Marta, Colombia. rbetancur@invemar.org.co. Accepted: Keywords Arius neogranatensis, Ariidae, sea catfishes, southern Caribbean Palabras clave Arius neogranatensis, Ariidae, bagres marinos, Caribe sur Abstract A new species of sea catfish (family Ariidae) from the Caribbean coast of Colombia, Arius neogranatensis n. sp., is described. It can be easily distinguished from other tropical western Atlantic ariid species by the presence of three pairs of barbels, one maxillary and two mental; supraoccipital process broader at base than distally, its base width slightly shorter than its length, in supraoccipital process length; predorsal plate narrow and crescent-shaped; teeth on palate villiform, forming a U-shaped pattern of four closely adjacent patches, the lateral pair largest and subtriangular; and by the lack of a fleshy furrow between the nostrils, a longitudinal fleshy groove in the median depression of the head, and gill rakers on rear surfaces of first two gill arches. So far the species is known only from brackish waters in a small sector of the central northern coast of Colombia. Resumen Se describe a Arius neogranatensis n. sp., una nueva especie de bagre marino (familia Ariidae) de la costa Caribe de Colombia. Esta especie se distingue fácilmente de otras especies de áridos del Atlántico occidental tropical por la presencia de tres pares de barbillones, uno maxilar y dos mentonianos; proceso supraoccipital más amplio en su base que en su extremo distal, la anchura de su base ligeramente más corta que su longitud, en la longitud supraoccipital; placa predorsal semilunar y estrecha; dientes palatinos villiformes, dispuestos en cuatro placas a manera de U, de tal forma que las laterales son más grandes que las mediales y de forma subtriangular; y por la carencia de un pliegue carnoso que conecte las narinas, un surco longitudinal en la depresión media de la cabeza y branquiespinas en la superficie posterior de los dos primeros arcos branquiales. Esta especie es hasta el momento conocida sólo de aguas salobres en un pequeño sector en la porción central de la costa norte de Colombia. Zusammenfassung Ein neuer Meereswels (Familie Ariidae) von der karibischen Küste Kolumbiens, Arius neogranatensis n. sp., wird beschreiben. Er kann leicht von anderen tropischen Westatlantik-Ariiden unterschieden werden durch seine drei Paar Barteln, eine Maxillar und zwei Mental; den supraoccipitalen Prozess der breiter ist an seiner Basis als in der Länge, seine Basenbrei - te etwas kürzer ist als seine Länge, in supraoccipitalem Prozess-Länge; Predorsale Platte schmal und halbmondförmig; Zähne auf dem Gaumen villiform, in Form von einem U-Muster in vier Plaken aufgeteilt, die Lateralen Paare sind grösser als die mittleren subtriangularen; und es fehlt eine fleischiche Falte welche die Nüstern verbindet, eine längliche Furche in der mittleren Kopfdepression, und Kiemenrechen auf dem hinteren Teil der ersten zwei Kiemenbogen. Die Art ist bisher nur aus dem Brackwasser der Zentralkolumbischen Küste bekannt. 5 Résumé Est décrite une espèce nouvelle de poisson-chat marin (famille des Ariidae) de la côte caraïbe de Colombie, Arius neogranatensis n. sp. On la distingue aisément des autres Ariidés de l'atlantique ouest tropical par la présence de trois paires de barbillons, l'une maxillaire et les deux autres inférieures, une excroissance supra-occipitale plus large à la base qu'à l'extrémité, la largeur de la base étant légèrement plus courte que sa longueur, 1,1-1,2 de la longueur de l'excroissance supra-occipitale; une plaque prédoraqua vol. 6 no

2 Description of a new species of sea catfish from Colombia, including an identification key for Caribbean ariid fishes sale étroite en forme de croissant; des dents palatales villiformes, présentant une disposition en forme de U de quatre implantations resserrées, la paire latérale étant plus grande et subtriangulaire; il se distingue aussi par l'absence de sillon carné entre les narines, un creux carné longitudinal à la dépression médiane de la tête et des branchiospines aux faces arrières des deux premiers arcs branchiaux. L'espèce n'est signalée jusqu'ici qu'en eaux saumâtres dans un secteur limité de la côte centre nord de la Colombie. Sommario Viene descritta una nuova specie di pesci gatto marini (famiglia Ariidae) della costa caraibica della Colombia, denominata Arius neogranatensis n. sp. Essa può essere agevolmente distinta dalle altre specie tropicali della famiglia che abitano l Atlantico occidentale, per avere tre paia di barbigli, uno mascellare e due nella regione del mento, il processo sopraoccipitale più allargato alla base che nella zona distale, con l ampiezza della base lievemente minore della lunghezza e compresa volte nella lunghezza stessa, la piastra predorsale stretta e a forma di luna, denti villiformi sul palato, formanti un disegno ad U risultante da quattro aree distinte e ravvicinate, dove le due laterali sono più slargate e subtriangolari, e per l assenza di una grinza carnosa estesa tra le narici, di un solco carnoso longitudinale nella depressione mediale del capo, e di rastrelli branchiali sulla superficie posteriore dei primi due archi branchiali. La specie è per ora nota solo in ambienti salmastri di una ristretta area geografica della costa centro-settentrionale della Colombia. Introduction The catfish family Ariidae includes approximately 130 species in the world s tropical and subtropical seas and fresh waters (Jayaram and Dhanze, 1986). The systematic and taxonomic status of neotropical ariids is chaotic, since some genera lack adequate definitions and many species are undescribed. Taylor and Menezes (1978) included 15 species in their lists of the central western Atlantic marine and brackish species of the family, presenting nine of them as Arius. Cervigón (1991) reported 12 ariid species from Venezuelam including nine of them in Arius. Mejía- Ladino et al. (in press) mentioned eight sea catfish species from the Colombian Caribbean, placing two of them in Arius. Recently, a new species of sea catfish was found in a small sector of the central northern coast of Colombia. That species has a very restricted geographical distribution, is under fishing pressure and a degree of environmental stress, making its legal protection urgent. For that reason, the species is herewith officially described as new. Materials and methods Counts and measurements were made following Allen and Fischer (1978); all measurements were made as the shortest line between two points. Width of the supraoccipital process was measured at the base of the process, where it originates from the skull; its length was measured from the midpoint of the base to its distal end. Head depth was measured at the anterior end of the supraoccipital keel. SL is standard length, HL is head length, TL is total length. The type material comes from the Caribbean coast of Colombia and is deposited in the fish collections of the Museo Colombiano de Historia Natural Marina, Instituto de Investigaciones Marinas y Costeras (INVEMAR- PEC), Santa Marta, Colombia, and of the Museo de Historia Natural of the Instituto de Ciencias Naturales, Universidad Nacional de Colombia (MHN-ICN), Bogotá, Colombia. Aditional squeletonized material was also examined: Fig. 1. Lateral view, holotype (INVEMAR-PEC 3754, 362 mm TL) of Arius neogranatensis n. sp., from the Colombian Caribbean. aqua vol. 6 no

3 Arturo Acero P. and Ricardo Betancur-R. A. neogranatensis n. sp., female, 289 mm SL (not deposited), collected by A. Roa, 28 April 2001, Ciénaga de Mestizo, San Antero, Córdoba, Colombia (9 25 N, W); A. cookei Acero P. and Betancur- R. 2002, male, 445 mm SL (not deposited), collected by S. Corro, 29 April 1999, río Santa María, Herrera, Panama, (8 9 N, W); A. kessleri Steindachner 1877, female, 281 mm SL (not deposited), purchased and identified by A. Acero, 20 October 1998, Buenaventura, Valle del Cauca, Colombia (3 55 N, W); Smithsonian Institution, National Museum of Natural History, Washington, DC, USA (USNM) , A. planiceps Steindachner 1877, one specimen, not sexed or measured, purchased 25 January 1984, Buenaventura, Valle del Cauca, Colombia. Arius neogranatensis n. sp. English name: Caribbean sculptured sea catfish Spanish name: Bagre parindera Figs. 1 and 2 Holotype: INVEMAR-PEC 3754, male, 299 mm SL. Collected by A. Roa, 31 May 2001, mouth of Río Tinajones medio, San Antero, Córdoba, Colombia (9 25 N, W) Paratypes: INVEMAR-PEC 3755 (female, 253 mm SL) and ICN-MHN 5722 (male, 265 mm SL), same data as the holotype. Diagnosis A western central Atlantic species of Arius characterized by the following combination of features: head length in SL; snout length in HL; width Fig. 2. Dorsal view, head of holotype (INVEMAR-PEC 3754, 80 mm HL) of Arius neogranatensis n. sp., from the Colombian Caribbean. of mouth in HL; interorbital distance in HL; no fleshy furrow between nostrils; no longitudinal fleshy groove in median depression of head; supraoccipital process broader at base than distally, its base width slightly shorter than its length, in supraoccipital process length; predorsal plate narrow and crescent-shaped; teeth on palate villiform, forming a U-shaped pattern of four closely adjacent patches, the lateral pair largest and subtriangular; no gill rakers on rear surfaces of first two gill arches. Meristic and morphometric data of the type series appears in Table I. Description Body relatively robust; its depth in SL; its width in SL. Head rounded and broad, slightly flattened above; its width in SL and in HL; its depth in SL and in HL. Snout overhanging, extends well forward of mouth. Mouth broad and inferior; lips relatively thick, upper lip width in HL. Three pairs of barbells (one maxillary and two mental), the maxillary pair relatively long, their length in SL, always passing base of pectoral-fin spines. Distance between anterior nostrils in HL. Distance between posterior nostrils in HL. Eye relatively small, in HL, in distance between anterior nostrils and in interorbital distance. Postorbital length in HL. Exposed head shield clearly visible, very rugose, extending anteriorly, almost reaching the eyes; a broad frontal depression present. Supraoccipital process somewhat narrow and keeled; its length in HL; its width in HL. Mandibular band of teeth somewhat exposed when mouth is closed; teeth pointed, fine, and strong. Inner pair of palatine patch of teeth smaller than laterals and separated medially. Gill rakers on first arch ; gill rakers on second arch Predorsal-fin length 2.7 in SL. Dorsalfin elements I,7; dorsal-fin base in SL; dorsalfin spine height in SL. Distance between dorsal fin and adipose fin in SL. Base of adipose fin in SL, longer than base of dorsal fin; height of adipose in SL. Pectoral-fin elements I,11; pectoral-fin base in SL; pectoral-fin spine length in SL, its inner margin with strong and curved serrations. Anal-fin elements 18-19; anal-fin base in SL. Caudal peduncle depth in SL. Colour in alcohol. Brownish on back, whitish below. Size. Largest specimen 362 mm in TL (holotype). Habitat and distribution A. neogranatensis has been collected only in a small portion of the northern Colombian coast; hence, it seems to be endemic to the Colombian Caribbean, having a very restricted range compared to other western central Atlantic ariid species. The examined material was collected in brackish waters. 7 aqua vol. 6 no

4 Description of a new species of sea catfish from Colombia, including an identification key for Caribbean ariid fishes Table I. Meristic and morphometric data on the holotype, paratype series and undeposited skeletonized specimen (USS) of Arius neogranatensis n. sp. For the paratypes and USS counts, figures between brackets indicate number of specimens with each count. Holotype measurements are given in millimeters, percentages of the standard length appear between brackets. Paratypes and USS measurements are given as a range; total length and standard length are expressed in millimeters, the additional measurements are expressed as percentages of the standard length. Holotype Paratypes and USS Sex Male Male (1), females (2) Dorsal-fin elements I, 7 I, 7 Pectoral-fin elements I, 11 I, 11 Pelvic-fin elements 6 6 Anal-fin elements 18 18(1)-19(2) Upper and lower gill rakers on 1st arch (1)-10(2) Total gill rakers on 1st arch 13 13(1), 14(2) Upper and lower gill rakers on 2nd arch (1)-4(2)+10(1)-11(2) Total gill rakers on 2nd arch 15 14(2), 15(1) Total length Standard length Body depth 56 (18.7) Body width 64 (21.4) Head length 80.4 (26.9) Head width 67.7 (22.6) Head depth 45.2 (15.1) Snout length 27.4 ( 9.2) Mouth width 48.1 (16.1) Upper lip width 5.9 ( 2.0) Maxillary barbels 79.1 (26.5) External mental barbels 40.4 (13.5) Internal mental barbels 28.7 ( 9.6) Anterior internarial distance 25.8 ( 8.6) Posterior internarial distance 23.4 (7.8) Interorbital distance 38.3 (12.8) Eye diameter 9 ( 3.0) Postorbital length 48.4 (16.2) Width of supraoccipital process 20.8 ( 7.0) Length of supraoccipital process 24.6 ( 8.2) Predorsal-fin length 110 (36.8) Dorsal-fin base 31.4 (10.5) Dorsal-fin spine height Distance between dorsal and adipose fins 73.6 (24.6) Preadipose-fin length 219 (73.2) Adipose-fin base 35.4 (11.8) Adipose-fin heigth 35.3 (11.8) Prepectoral-fin length 66 (22.1) Pectoral-fin base 19.3 ( 6.5) Pectoral-fin spine length Prepelvic-fin length 159 ( 53.2) Pelvic-fin base 19.9 ( 6.7) Pelvic-fin length 48.8 (16.3) Preanal-fin length 213 (71.2) Anal-fin base 45.2 (15.1) Anal-fin height 44.9 (15.0) Caudal peduncle depth 19 ( 6.4) aqua vol. 6 no

5 Arturo Acero P. and Ricardo Betancur-R. Comments After examining ariid osteological material from both American coasts, there are clear morphological trends in neurocranium structure between A. planiceps, A. kessleri and A. cookei, from the eastern Pacific, and the Caribbean sculptured sea catfish (unpublished data; R. Cooke, pers. comm., 2002; Fig. 3). Acero and Betancur-R. (2002), in describing A. cookei, commented that the similarities shared by that one and other four eastern Pacific species could be an indication of phylogenetic affinity. Since A. neogranatensis shows the same morphological trends, it seems that its closest relatives are a group of eastern Pacific species including A. kessleri, A. cookei, A. planiceps, A. osculus, and the undescribed catfish called Arius species A by Kailola and Bussing (1995). Therefore, the distribution of A. neogranatensis, apparently restricted to a small area of the southern Caribbean, may be due to an imagined event, the rising of the Panama isthmus occurred at least 3.5 Ma (Coates and Obando, 1996). Such an event may have led to the allopatric speciation of A. neogranatensis from its putative relatives. Any conclusions on this subject should await consistent phylogenetic evidence of the relationships of A. neogranatensis. At this time, the placement of this species and other New World sea catfishes in the genus Arius is provisional (Kailola and Bussing, 1995; Acero, in press). A proper decision on this may be only be reached after a detailed systematic examination of the type species of the genus, A. arius. The key for the western central Atlantic ariids prepared by Taylor and Menezes (1978) led to the identification of A. neogranatensis material as A. phrygiatus, a species restricted to eastern Venezuela and the Guianas, based on the presence of a crescentshaped predorsal plate, much shorter than the supraoccipital process, a long, narrow supraoccipital process tapering posteriorly, and similar totals of gill rakers counts in the first (13-14 in A. neogranatensis, in A. phrygiatus) and second (14-15 in A. neogranatensis, in A. phrygiatus) arches. Nevertheless, A. neogranatensis can be easily distinguished from A. phrygiatus by its four closely adjacent patches of palatine teeth, arranged in a U- shaped pattern (only two small rounded or elliptical widely-separated patches in A. phrygiatus). Fig. 3. Dorsal view, neurocraniums of A. neogranatensis from the Caribbean Sea (105 mm skull length, upper left) A. kessleri (104 mm skull length, upper right), A. planiceps (69 mm skull length, lower left), and A. cookei (179 mm skull length, lower right) from the tropical American Pacific. Etymology The specific epithet neogranatensis refers to the New Granada, the oldest name given to Colombia by the Spaniard conquerors, because the new species seems to be endemic to that South American country. We propose as the official common English name Caribbean sculptured sea catfish, since it seems to be close to the Pacific species, the sculptured sea catfish (A. kessleri) and the false sculptured sea catfish (Arius cookei). 9 aqua vol. 6 no

6 Description of a new species of sea catfish from Colombia, including an identification key for Caribbean ariid fishes Key to the species of the family Ariidae present in the Caribbean Sea (modified from Taylor and Menezes, 1978) 1a. Only two pairs of barbels, one of which is mental; maxillary barbels and filaments of dorsal- and pectoral-fin spines appearing as long, flattened ribbons...2 1b. Three pairs of barbels, one pair maxillary and two pairs mental, all round in cross section...3 2a. Anal fin comparatively short, with 22 to 28 rays....bagre marinus 2b. Anal fin comparatively long, with 29 to 37 rays......bagre bagre 3a. A furrow, partially covered by a flap of skin, extending across snout, connecting posterior nostrils...selenaspis herzbergii 3b. No fleshy furrow between posterior nostrils a. No longitudinal fleshy groove in median depression of head; no gill rakers on rear surfaces of first two gill arches...5 4b. A longitudinal fleshy groove in median depression of head variously developed or absent; gill rakers present on rear surfaces of first two gill arches (minute and few in Ariopsis)...7 5a. Predorsal plate enlarged, variously shieldshaped, its length more than one-half of supraoccipital process...arius proops 5b. Predorsal plate chevron- or crescent-shaped, much shorter than supraoccipital process a. Supraoccipital process usually narrower at base than distally, with nearly parallel sides, or the sides variously expanded distally into a large rounded plate...arius grandicassis 6b. Supraoccipital process broader at base than distally, the sides converging posteriorly to meet the predorsal plate...arius neogranatensis n. sp. 7a. Teeth on palate molariform in most species, arranged in a small patch on each side; gill rakers well-developed and uniformly distributed along rear surfaces of first gill arches......genus Cathorops. 7b. Teeth on palate small, villiform, arranged in two patches on each side (two small rounded median patches and two larger obovate lateral patches); gill rakers on rear surfaces of first two arches tiny, usually three to five in number and confined to upper limb of each arch...8 8a. Longitudinal fleshy groove in median depression of head very short; anterior gill rakers (total number) on first arch 16 to 18; anterior gill rakers (total number) on second arch 18 to 22; number of vertebrae free from Weberian complex 43 to 46...Ariopsis assimilis 8b. Longitudinal fleshy groove in median depression of head moderate in length; anterior gill rakers (total number) on first arch 17 to 20; anterior gill rakers (total number) on second arch 19 to 24; number of vertebrae free from Weberian complex 45 to 47...Ariopsis bonillai Acknowledgements A. Roa-Varón donated the type series; Dr. R. Cooke discussed with us the relationships of the new species; L.M. Mejía took the photograph of the holotype. COLCIENCIAS and Universidad Nacional de Colombia funded this study through proposal References Acero P., A. In press. Family Ariidae. In: Western Central Atlantic (Fishing Area 31) FAO species identification sheets for fishery purposes (Ed. K.E. Carpenter). FAO, Rome. Acero P., A. & R. Betancur-R Arius cookei, a new species of ariid catfish from the tropical American Pacific. Aqua, 5 (4): Allen, G. R. & W. Fischer Bony fishes. In: FAO species identification sheets for fishery purposes. Western Central Atlantic (Fishing Area 31). (Ed. W. Fischer). Vol. I, FAO, Rome. Cervigón, F Los peces marinos de Venezuela. Second edition. Vol. 1. Fundación Científica Los Roques, Caracas, 423 pp. Coates, A. G. & J. A. Obando The geologic evolution of the Central American isthmus. In: Evolution and enviroment in tropical America (Eds. J. B. C. Jackson, A. F. Budd and A. G. Coates) University of Chicago Press, Chicago. Jayaram, K. C. & J. R. Dhanze Evolution and biogeography of the Indian genera of the family Ariidae. Proceedings of the Indian Academy of Sciences (Animal Sciences) 95(2): Kailola, P. J. & W. A. Bussing Ariidae. In: Guía FAO para Identificacising. y of Sciences (Animal Sciences)phy of the Indian genera of th. Vol. II, Part 1. (Eds. W. Fischer, F. Krupp, W. Schneider, C. Sommer, K. E. Carpenter and V. Niem) FAO, Rome. Mejía-Ladino, L.M., R. Betancur-R. & A. Acero P. In press. Presencia de Arius grandicassis en el Caribe colombiano, incluyendo una clave para la identificación de los peces de la familia Ariidae en el área. Boletín de Investigaciones Marinas y Costeras, 31. Taylor, W. & N. Menezes Family Ariidae. In: Western Central Atlantic (Fishing Area 31) (Ed. W. Fischer). FAO species identification sheets for fishery purposes. FAO, Rome, Tome I. aqua vol. 6 no