Cathorops multiradiatus

Alexandre P. Marceniuk, 2007, Description of Cathorops manglarensis, a new species from the Colombian Pacific, with redescription of Cathorops multiradiatus (Siluriformes; Ariidae)., Zootaxa 1529, pp. 33-48 : 40-46

Cathorops multiradiatus

(fig. 7 and 8)

Bagrus arioides Kner, 1863 : 227, fig. 15 [ Type locality: río Bayano, Panama. Holotype: ZSM destroyed. Preoccupied by Bagrus arioides Valenciennes, 1840 , objectively invalid].

Arius multiradiatus Guenther, 1864 : 173 [New name for Bagrus arioides Kner, 1863 . No type designated].- Regan, 1906: 126 and 128 [Panama; diagnosis in key; synonymy; brief redescription].- Meek & Hildebrand, 1923: 122 and 123 [ Panama: Chame Point, Balboa, Panama City Market ; diagnosis in key; redescription].- Hildebrand, 1946: 127, fig. 28 [ Ecuador: Gulf of Guayaquil off Puerto Pizarro , Panama: Panama Bay ; synonymy; redescription; distribution].

Tachisurus multiradiatus .- Eigenmann & Eigenmann, 1888: 146 [only name].- Eigenmann & Eigenmann, 1890: 50 and 92 [diagnosis in key; synonymy; distribution].

Tachysurus multiradiatus .- Jordan & Evermann, 1896: 121 and 132 [diagnosis in key; synonymy; brief redescription].

Tachysurus emmelane Gilbert, 1898 : 2785 [ Type locality: Panama. Holotype: SU 5818 ].- Gilbert & Starks, 1904: 31, pl. 6, figs. 11 and 11a [ Panama: Panama Bay ; redescription].

Tachysurus equatorialis Starks, 1906 : 766 [ Type locality: Guayaquil, Ecuador. Holotype: USNM 53470 ].- Evermann & Radcliffe, 1917 [Ecuador; redescription].

Cathorops multiradiatus .- Allen & Robertson, 1994: 69 [ new combination].- Kailola & Bussing, 1995: 862 and 881 [diagnosis in key; synonymy; redescription].- Chirichigno & Vélez, 1998: 160 [Peru; diagnosis in key].- Eschmeyer et al., 1998 [synonymy, distribution].- Marceniuk & Ferraris, 2003: 449 [synonymy, distribution].- Ferraris, 2007: 40 [synonymy, distribution].

Diagnosis. Cathorops multiradiatus can be distinguished from all congeners by the following combination of characters: 16-19 gill rakers on first arch; 15-18 gill rakers on second arch; 25-27 anal fin rays; posterior margin of pectoral fin spine with long and conspicuous serrations.

Additional characters help distinguish this species from each of its congeners from the Pacific coast of Central and South America. Cathorops multiradiatus is distinguished from C. dasycephalus in possessing vomerine tooth plates absent (vs. vomerine tooth plates present) and osseous bridge formed by lateral ethmoid and frontal without granulation (vs. granulated osseous bridge along its length). Cathorops multiradiatus differs from C. fuerthii in having medial groove of neurocranium deep and large, with lateral margins regular and progressively narrower posteriorly (vs. median groove narrow and shallow, with irregular margins along its length), shorter distance between posterior nostrils (5.1-5.8 vs. 5.8-7.3% SL), larger orbital diameter (4.1-5.2 vs. 3.7-4.1% SL), accessory tooth plates shorter (2.1-2.8 vs. 3.9-4.9% SL) and narrower (0.7-1.2 vs. 1.6- 2.2% SL), and shorter pectoral fin spine (16.9-18.7 vs. 19.5-21.0% SL). Cathorops multiradiatus differs from C. hypophthalmus in possessing a shorter distance between anterior nostrils (3.7-4.5 vs. 6.9-7.1% SL) and between posterior nostrils (5.1-5.8 vs. 8.2-8.5% SL), larger orbital diameter (4.1-5.2 vs. 3.0-3.5% SL), shorter external mental barbel (18.4-24.6 vs. 34.5-38.1% SL), shorter internal mental barbel (8.6-16.7 vs. 26.1-31.2% SL), and shorter dorsal fin spine (18.2-21.3 vs. 25.0-25.2% SL). Cathorops multiradiatus differs from C. manglarensis in possessing a shorter maxillary barbel (22.9-27.7 vs. 28.4-38.2% SL) (fig. 3), shorter pectoral fin spine (16.9-18.7 vs. 18.5-22.5% SL), dorsal fin spine longer than pectoral fin spine (vs. dorsal fin spine shorter than pectoral fin spine) (fig. 4), and shorter and narrow accessory tooth plates, with small and few molariform teeth (fig. 9) (vs. longer and wider accessory tooth plates, with large and numerous molariform teeth) (fig. 5). Cathorops multiradiatus differs from C. tuyra in possessing a shorter distance from tip of snout to dorsal fin origin (31.2-34.8 vs. 34.5-39.8% SL), shorter supraoccipital process (9.8-11.5 vs. 11.3- 13.7% SL), and accessory tooth plates and dentary with relatively small molariform teeth (vs. accessory tooth plates and dentary with very large molariform teeth).

Description. (Table 1 and 3). Head moderately long and depressed, profile slightly convex at level of frontals and supraoccipital. Body wider than deeper on pectoral girdle area. Cephalic shield moderately granulated and visible under skin, moderately long and broad on lateral ethmoid and epioccipital area and narrow on frontal and supracleithrum areas. Osseous bridge formed by lateral ethmoid and frontals slender and visible under skin. Medial groove of neurocranium formed by frontals and supraoccipital very distinct, deep and large, progressively narrower posteriorly. Supraoccipital process of moderate length and funnel shaped, its posterior part considerably narrower than its base and profile moderately convex. Nuchal plate half moon shaped, long and wide. Snout round in transverse section. Anterior and posterior nostrils closer among themselves. Eyes lateral and relatively large. Interorbital distance and distance between nostrils and orbit large. Short maxillary barbel, reaching base of pectoral fin spine and moderately long mental barbels, external mental pair reaching margin of gill membrane, internal pair not reaching margin of gill membrane.

Mouth of moderate size, lower jaw moderately arched. Lips moderately thick, lower thinner than upper. Vomerine tooth plates absent. One pair of elongated and narrow oval shaped accessory tooth plates, quite small and distant from each other. Accessory tooth plates with small molariform teeth. Premaxillary moderately long and wide. Dentary with posterior projection poorly development or absent, with many sharp teeth on anterior portion and few small molariform teeth on posterior portion. Sixteen to nineteen (19) acicular gill rakers on first arch, 6 (6) on upper limb, 10-13 (13) on lower limb. Fifteen to eighteen (17) spike shaped gill rakers on second arch, 4-5 (5) on upper limb, 10-13 (12) on lower limb.

Ten to eleven (10) soft pectoral fin rays. Pectoral fin spine short and thin; anterior margin granulated on two thirds, serrated on distal third; posterior margin straight on basal fourth, distal three quarters with quite long serrations. Seven (7) dorsal fin rays. Dorsal fin spine of moderate length and thin, longer than pectoral fin spine; anterior margin granulated on basal two thirds, distal third serrated; posterior margin serrated almost all its length. Six (6) pelvic fin rays, low and length of base long. Adipose fin small, its base less than half as long as anal fin base. Twenty-five to twenty-seven (27) anal fin rays, low and length of base long. Upper and lower lobes of caudal fin of moderate length, upper longer than lower. Caudal peduncle high. Lateral line reaching base of caudal fin upper lobe.

Coloration in alcohol. Head dark brown on dorsal and lateral portions, ventrally whitish. Body with same dark brown color on dorsal portion, progressively lighter towards lateral line and whitish under lateral line, with few brown spots. Barbels dark brown. All fins dark beige overall.

Sexual dimorphism. Sexual dimorphism was observed in 1 female (174.0 mm SL) and 4 males (120.0- 209.0 mm SL) with respect to following morphological features (Table 3).

Males with relatively longer and wider head than females, as expressed by longer head, longer snout, greater distance between nostrils and orbit, greater distance between lateral horn of lateral ethmoid and external branch of supracleithrum, greater distance from tip of snout to posterior margin of medial groove of neurocranium, greater distance from tip of snout to dorsal and anal fins origin, greater interorbital distance, greater distance between nostrils, and wider cephalic shield on lateral ethmoid, frontal and epioccipital areas. Males have wider body than females.

Females with larger accessory tooth plates than males (fig. 9) and males with accessory tooth plates generally covered by epithelial tissue. Dentary in females with a longer posterior expansion and larger and more molariform teeth on posterior portion than males (fig. 9).

Pelvic fin and maxillary barbel longer in females than in males. Males present longer pectoral and dorsal fin spines, relatively longer caudal fin lower lobe, and deeper caudal peduncle than females.

Distribution. The literature indicates that C. multiradiatus occurs from Guatemala to Paita, Peru (Hildebrand, 1946; Kailola & Bussing, 1995). The examined specimens are from Panama and Colombia (fig. 6). Common in shallow coastal areas and mangrove regions.

Remarks. Kner (1863) described Bagrus arioides based on one specimen collected in the River Bayano, in Panama. The name is preoccupied by a species described by Valenciennes (1840) from Bengal, India. Homonymy was recognized by Günther (1864), who proposed Arius multiradiatus as a replacement for Bagrus arioides Kner, 1863 . According to Article 59 (a) of the International Code of Zoological Nomenclature (1999), which deals with cases of primary homonyms, Bagrus arioides Kner, 1863 must be definitely rejected and recognized as an invalid senior synonym of Cathorops multiradiatus ( Guenther, 1864) . The specimen examined by Kner (1863) was destroyed (personal communication of Dirk Neumann) and C. multiradiatus may be recognized by its original description, partially reproduced by Günther (1864), with the number of anal-fin rays was long identified as an exclusive characteristic of the species within the genus (Eigenmann & Eigenmann, 1890; Jordan & Evermann, 1896; Regan, 1906; Meek & Hildebrand, 1923; Hildebrand, 1946; Kailola & Bussing, 1995). Cathorops manglarensis has a similar number of anal-fin rays, rendering the recognition of C. multiradiatus imprecise, if based exclusively on its original description. Given the loss of the holotype, the previously only known type specimen of B. arioides , a neotype is herein designated to insure the stability of the name and to avoid future doubts concerning the identity of the species. The specimen chosen as neotype of C. multiradiatus is a male of 192.0 mm SL, from the Bay of Panama, belonging to the National Museum of Natural History (USNM 79408).

The nominal species Tachysurus emmelane Gilbert, 1898 and Tachysurus equatorialis Starks, 1906 , are recognized as junior synonyms of C. multiradiatus . The determination of the specific status of both nominal species is based on their original descriptions. Tachysurus emmelane Gilbert, 1898 was described based on one specimen of 280 mm TL, colleted in Panama. The original description presents characteristics of the species common to C. multiradiatus , which also distinguishes it from C. manglarensis : “posterior mandibular (dentary) teeth stronger than those in front bluntly conic, not, however, granular or flat and pavement like (molariform), as are the posterior mandibular teeth in T. fuerthii , T. melanopus and T. liropus ”, “palatine (accessory tooth plates) teeth granular (molariform), in small oblanceolate patches, which taper to a point laterally, and are widely separated on medial line, the patches agreeing in size and shape with those in T. liropus ”, “the maxillary barbels reaching edge of gill membrane in front of pectoral spine, the outer mental barbels extending beyond gill membrane, ..., the inner not to edge of membrane”, “gill rakers 6 + 13”, “dorsal spine ... its length to tip of calcified portion 1 2/5 in head” and “pectoral spine strong, ridged and granulated in front, the hinder edge with very strong serrae; length of spine 1 ¾ in head”. Additionally, the type specimen of T. emmelane was examined by Dave Catania (Department of Ichthyology, California Academy of Sciences), that sent the following data on the type: 6 + 13 gill rakers on first gill arch; 6 + 13 gill rakers on second gill arch; maxillary barbel 52.4 mm (22.8 % SL) (fig. 3); pectoral fin spine 41.5 mm (17.9 % SL) (fig. 4); dorsal fin spine 44.8 mm (19.5 % SL and longer than pectoral-fin spine) (fig. 4); pectoral fin spines with long and conspicuous serrations on posterior surface.

Starks (1906) described Tachysurus equatorialis based on only one specimen from Guayaquil, Ecuador. Tachysurus equatorialis differs from C. manglarensis and may be recognized as a synonym of C. multiradiatus based on the following characteristics presented in its original description: “palatine patches (accessory tooth plates) small, elliptical, and widely separated, each bearing about 30 bluntly rounded teeth (molariform); length of each patch two-fifths of length of eye and half as wide as long”, “posterior, median, mandibular(dentary) teeth not enlarged as in other species”, “maxillary barbel reaching to axillary pore; posmental barbel to base of pectoral spine; and mental barbel to base of branchiostegal membrane” and “gill rakers .... 6 + 13 in number”. The condition of T. equatorialis as a synonym of C. multiradiatus is also based on observations done by Hildebrand (1946). The author redescribed C. multiradiatus based on the examination of three specimens from the Gulf of Guayaquil and on specimens examined by Evermann & Radcliffe (1917), on which the authors based their redescription of Tachysurus equatorialis (USMN 77596). Hildebrand (1946) compared the cited specimens with specimens from Panama identified as C. multiradiatus and the type-specimen of T. equatorialis (USNM 53470), recognizing that all of them did not differ meaningfully from each other and probably represent the same species. Additionally, the type specimen of T. equatorialis was examined by Carl J. Ferraris (California Academy of Sciences) and Richard P. Vari (Division of Fishes, Smithsonian Institution) and the latter sent the following data on the type: 6 + 14 gill rakers on first gill arch; 5 + 13 gill rakers on second gill arch; maxillary barbel 35.5 mm (18.6% SL) (fig. 3); pectoral fin spine broken; dorsal fin spine broken; pectoral fin spines with long and conspicuous serrations on posterior surface.

Material Examined. Neotype (herein designated): USNM 79408 (male, 192.0 mm SL) Panama, Panama Bay, Balboa, canal zone, May 05 and 06 1911, Meek, S. E. & Hildebrand, S. F. USNM 388315 (1, 209.0 mm SL) collected with neotype ; USNM 292703 (1, 174.0 mm SL) Colombia, Sandy Beach immediately South of Punta Canchaco in enseada de Juan Chaco, about 1, 1/2 hrs. by motor boat north of Buenaventura (03° 56' 40" N 77° 21' W), Sep 18 1969, Knapp, L. ; USNM 00286400 (3, 120.0-125.0 mm SL) Colombia, off Cape Manglares, south of Tumaco (01° 39' 00" N 79° 02' 30" W to 01° 37' 30" N 79° 02' 00" W), Oct 27 1970, Knapp, L.