Gymnotus carapo occidentalis, Albert, 2017

Albert, James S., 2017, Revision of the polytypic electric fish Gymnotus carapo (Gymnotiformes, Teleostei), with descriptions of seven subspecies, Zootaxa 4318 (3), pp. 401-438 : 429-430

Gymnotus carapo occidentalis New Subspecies

Figure 3 E, Tables 3 and 4

Holotype: UF 126181, 272 mm, Peru, Loreto, Río Pacaya, Cocha Zapote (05°20’02”S, 074°29’05”W).

Paratypes: UF 126181, 245 mm, Peru, Loreto, Río Pacaya, Cocha Zapote (05°20’02”S, 074°29’05”W).

Non-Types: ANSP 203173 (20) 105–263 mm, Peru, Loreto, Cocha Santo Tomás aff. Río Nanay near Iquitos. INHS 55038 (1) 323 mm, Peru, Loreto, Río Napo aff. Amazon. INPA 6390 (1) 450 mm, Brazil, Mato Grosso, Aripuanã, Río Aripuanã, Igarapé Castanhal. MUSM 11590 (5), 193–211 mm, Cuenca Ebehuabaeji, Sandia. MUSM 58770 (20) 86–275 mm, Peru, Loreto, Cocha Santo Tomás aff. Río Nanay near Iquitos (03°47’59.92”S, 073°20’14.48”W). MZUSP 76061 (1), 260 mm, Brazil, Amazonas, Río Tefé, Lago Tefé, Cabeçeira do Lago Tefé (03°34’35”S, 064°59’19”W). MZUSP 76063 (1), 298 mm, Brazil, Amazonas, MSDR, Ressaca da Vila Alencar (03°07’42”S, 064°48’02”W). MZUSP 76064 (1), 253 mm, Brazil, Amazonas, MSDR, Cano do Lago Mamirauá (03°04’26”S, 064°48’39”W). NRM 27650 (1), 305 mm, Peru, Loreto, Río Samiria, Maynas, right bank stream tributary between Caño Pastos and Hamburgo (05°2’S, 075°08’W). NRM 27650 (1), 305 mm, Peru, Loreto, Río Samiria, Maynas, right bank stream tributary between Caño Pastos and Hamburgo (05°12’S, 075°08’W). NRM 40772 (1), 91 mm, Peru, Loreto, Río Maniti, Maynas, 50 km NE of Iquitos (03°29’S, 072°44’W). NRM 40772 (1), 91 mm, Peru, Loreto, Río Maniti, Maynas, 50 km NE of Iquitos (03°29’S, 072°44’W). UF 116573 (2), 189–279 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay. UF 116665 (1), 298 mm, Peru, Loreto, Río Nanay, Maynas, 3 km upstream Mishana, Reserva Allpahuayo-Mishana (03°52’05”S, 073°29’03”W). UF 116665 (1), 298 mm, Peru, Loreto, Río Nanay, Maynas, 3 km upstream Mishana, Reserva Allpahuayo-Mishana (03°52’05”S, 073°29’03”W). UF 122820 (1), 275 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay. UF 122821 (1), 331 mm, Peru, Loreto, acquired from fishermen 28 May, 2002, Río Amazonas near Iquitos, Loreto Department, Peru (03°46’S, 073°15’W). UF 122822 (1), 330 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay. UF 122822 (1), 334 mm, Peru, Loreto, acquired from fishermen 28 May, 2002, Río Amazonas near Iquitos, Loreto Department, Peru (03°46’S, 073°15’W). UF 122825 (1), 158 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay. UF 122825 (1), 158 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay. UF 122847 (1), 188 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay. UF 122847 (1), 188 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay. UF 122848 (1), 112 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay. UF 122849 (1), 132 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay. UF 122849 (1), 132 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay. UF 122852 (1), 92 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay. UF 128991 (1) 291–307 mm, Peru, Loreto, Ucayali, (05°18’7.3”N, 074°03’36.03”W). UF 131129 (1) 172 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay (03°45”S, 073°15’W). UF 131129 (1), 172 mm, Peru, Loreto, Río Amazonas, Maynas, Río Nanay, near Iquitos. UFRGS 22695 (23) 104–266 mm, Peru, Loreto, Cocha Santo Tomás aff. Río Nanay near Iquitos. UMMZ 228999 (1), 162 mm, Peru, Loreto, Río Tahuayo (04°10’S, 073°12’W). UMMZ 230733 (1), 251 mm, Peru, Loreto, Río Yavari, Buen Suceso, Quebrada Carana (04°08’S, 070°26’W). UMMZ 230733 (1), 251 mm, Peru, Loreto, Río Yavari, Buen Suceso, Quebrada Carana (approx. 04°08’S, 070°26’W). UMMZ 230734 (2), 190–210 mm, Brazil, Santa Cruz, Benjamin Constante, Río Nanay Río Nanay, Río Cayari (04°22’S, 070°02’W). ROM 83885 (1) 233 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 83886 (1) 238 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 83887 (1) 210 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 89520 (1) 189 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 89583 (1) 278 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 89660 (1) 176 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 89661 (1) 158 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 89662 (1) 132 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 93388 (1) 246 mm, Guyana, Essequibo, Cuyuni- Mazaruni. ROM 93389 (1) 238 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 93407 (1) 248 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 93424 (1) 245 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 93425 (1) 205 mm, Guyana, Essequibo, Cuyuni-Mazaruni. ROM 93426 (1) 186 mm, Guyana, Essequibo, Cuyuni-Mazaruni.

Description: Specimens of G. carapo from the western Amazon overlap substantially in morphometric and meristic PC-space with specimens from other localities ( Figures 4 , 5 , and 12). Gymnotus carapo occidentalis is characterized by the following combination of statistically significant (p <0.01) traits when compared to the rest of the species as a whole (see Principal Components Analyses and t-tests): long head (HL 11.4%–15.5% TL, mean 13.1% TL vs 10.2%–14.0%, mean 12.4% in all other subspecies), short preorbital distance (PR 28.0%–39.1% HL, mean 34.2% vs. 31.0%–40.2%, mean 35.3% in all other subspecies), narrow mouth (MW 32.2%–45.2% HL, mean 38.3% vs. 32.9%–49.0%, mean 42.2% in all other subspecies), short interorbital distance (IO 31.9%–40.6% HL, mean 35.6% vs. 32.9%–44.8%, mean 38.1% in all other subspecies), slender body (BD 63.7%–95.2% HL, mean 80.9% vs. 42.7%–106.6%, mean 86.4% in all other subspecies), slender head (HD 44.0%–62.5% HL, mean 56.2% vs. 50.8%–72.4%, mean 59.5% in all other subspecies) and narrow head (HW 50.0%–63.4% HL, mean 58.4% vs. 49.1%–67.7%, mean 60.2% in all other subspecies).

Distribution: Known from the western Amazon basin including Department of Loreto, Peru, the Río Aripuanã in the state of Mato Grosso, Brazil and the Amazon at Tefé in Brazil. Also known from the Cuyuni-Mazaruni in Essequibo basin of Guyana and the Napo basin in Ecuador ( Figure 2 B).

Etymology: Subspecific epithet derived from the Latin “ occidentalis ” meaning “of the West”.

Figures

FIGURE 2. Geographic distribution of Gymnotus carapo. A. Closed circles show 111 localities of specimens used in morphometric analyses, and open circles show 191 other verified G. carapo localities. B. Collection localities color coded by subspecies. Note G. carapo is absent from the interior of the Brazilian shield and the Atlantic coast of Brazil from Ceará to Rio Grande do Sul.

FIGURE 3. Specimens illustrating variation in body shape and color pattern among seven subspecies of Gymnotus carapo A. G. c. australis, MLP 11222, 289 mm, Argentina, Misiones province, Río Iguazú basin, Arroyo Verde (25 ° 40 ’ 15 ” S, 053 ° 56 ’ 00.8 ” W); B. G. c. caatingaensis, AUM 20624, 225 mm. Brazil, Piauí, Río Gurgueia aff. Río Parnaíba (08 ° 32 ’ 24 ” S, 044 ° 25 ’ 48 ” W); C. G. c. carapo, UMMZ 190414, 146 mm. Suriname, Brokopondo, Marshal Kreek, aff. Suriname River (05 ° 14 ’ 24.9 ” N, 055 ° 05 ’ 58.6 ” W); D. G. c. madeirensis, UMSS 0 6964, 178 mm. Brazil, Amazonas, Río Beni (10 ° 51 ’ 44.302 ” S, 066 ° 04 ’ 50.300 ” W); E. G. c. occidentalis, UF 122820, 279 mm. Peru, Loreto, Iquitos (03 ° 43 ’ 51.73 ” S, 073 ° 15 ’ 3.83 ” W); F. G. c. orientalis, MCZ 45189, 165 mm. Brazil, Para, Parauapebas, Río Arari, Ilha de Marajó (01 ° 01 ’ S, 048 ° 58 ’ W); G. G. c. septentrionalis, ROM 83885, 233 mm. Guyana, Essequibo, Río Mazaruni (04 ° 55 ’ 33.208 ” N, 060 ° 36 ’ 53.784 ” W). Scale bars = 10 mm.

FIGURE 4. Landmarks used for geometric morphometric analyses. Fifteen landmarks were recorded for 88 morphologically mature specimens from seven subspecies of G. carapo Landmarks: 1) tip of snout; 2) tip of maxilla; 3) margin of maxilla; 4) external naris; 5) second pore of the supraorbital laterosensory canal; 6) point directly above midline of eye; 7) supraoccipital crest; 8) base of first anal fin ray; 9) anus; 10) seventh pore of the posterior marginal laterosensory canal; 11) anterior margin of eye; 12) posterior margin of eye; 13) top of preopercle; 14) top of opercle; 15) base of most ventral pectoral fin ray.

FIGURE 5. Principal components analysis of linear measurements for 175 specimens from seven subspecies of G. carapo: G. c. australis (AU, n = 25), G. c. caatingaensis (CT, n = 8), G. c. carapo (CA, n = 31), G. c. madeirensis (MD, n = 13), G. c. occidentalis (OC, n = 65), G. c. orientalis (OR, n = 16) and G. c. septentrionalis (SE, n = 15). Head length, head depth, body width and body depth load heavily on PC 1, while pre- and postorbital (PR and PO, respectively) and preanal (PA) lengths load heavily on PC 2. Note the substantial overlap in PC space between subspecies.