Gymnotus carapo madeirensis, 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 : 428-429

Gymnotus carapo madeirensis New Subspecies

Figure 3 D, Tables 3 and 4

Holotype: MUSM 12949, 227 mm, Peru, Puno, Sandia, Río Candamo (13°31’S, 069°41’W).

Paratypes: MUSM 12949 (2), 101–121 mm, Peru, Puno, Sandia, Río Candamo (13°31’S, 069°41’W).

Non-Types: MUSM 12949 b (4), 101–227mm, Peru, Puno, Sandia, Río Candamo , (13°25’S, 070°01’W) . UF 82191 (1), 187 mm, Bolivia, Santa Cruz, Río Guaporé, Río San Pablo, Río San Diablo , Velasco, 71 km N. San José de Chiquitos (17°18’S, 060°35’W) . UF 82211 (2), 196–205 mm, Bolivia, Santa Cruz, Río Guaporé, Río San Pablo, Chiquitos, Comunidad La Esperanza , ca. 40 km N. San José de Chiquitos (17°25’S, 060°47’W) . UF 82345 (3) 111– 360 mm, Bolivia, Santa Cruz, Río Jorge, W. Warnes, Río Piray (17°34’12.0”S, 063°12’36.0”W) . UF 82470 (2), 170–218 mm, Bolivia, Beni, Río Mamoré, Río Ibaré , Cercado, Arroyo San Javier (14°38’S, 064°53’W) . UF 82485 (1), 360 mm, Bolivia, Beni, Río Mamoré, Río Ibaré , Cercado, 20 km N San Javier (14°28’S, 064°56’W) . UMSS 0 6969 (1), 302 mm, Bolivia, Beni, Río Madeira, Arroyo Tres Cuchillas (10°49’23.016”N, 066°04’50.30”W) . UF 82510 (1), 241 mm, Bolivia, Beni, Río Mamoré, Río Ibaré , Cercado, 25 km N San Javier (14°24’S, 064°56’W) . UMMZ 66433 (2), 215–331 mm, Bolivia, Beni, Río Beni, Lago Rogoagua (13°57’S, 066°58’W) . UMSS 0 6962 (1), 108 mm, Bolivia, Beni, Río Madeira, Arroyo Tres Cuchillas (10°49’23.016”N, 066°04’50.3”W) . UMSS 0 6963 (1), 121 mm, Bolivia, Beni, Río Madeira, Arroyo Tres Cuchillas (10°49’23.016”N, 066°04’50.3”W) . UMSS 0 6964 (1), 174 mm, Bolivia, Beni, Río Madeira, Arroyo Tres Cuchillas (10°49’23.016”N, 066°04’50.3”W) . UMSS 0 6964 (1), 177 mm, Bolivia, Beni, Río Madeira, Arroyo Tres Cuchillas (10°49’23.016”N, 066°04’50.30”W) . UMSS 0 6965 (1), 145 mm, Bolivia, Beni, Río Madeira, Arroyo Tres Cuchillas (10°49’23.016”N, 066°04’50.3”W) . UMSS 0 6966 (1), 179 mm, Bolivia, Beni, Río Madeira, Arroyo Tres Cuchillas (10°49’23.016”N, 066°04’50.3”W) . UMSS 0 6970 (1), 119 mm, Bolivia, Beni, Río Madeira, Arroyo Tres Cuchillas (10°49’23.016”N, 066°04’50.3”W) . UMSS 0 6977 (1), 202 mm, Brazil, Amazonas, Río Beni aff. Río Madeira (11°01’41.2”S, 066°05’58.801”W) .

Description: Specimens of G. carapo from the Río Madeira basin overlap substantially in morphometric and meristic PC-space with specimens from other localities ( Figures 4 , 5 , and 12). Gymnotus carapo madeirensis 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): short head (HL 10.4%–13.7% TL, mean 11.7% vs. 10.2%–15.5%, mean 12.7% in all other subspecies), wide interorbital distance (IO 37.7%–44.8% HL, mean 41.0% vs. 31.9%–43.6%, mean 37% in all other subspecies), deep body (BD 85.9%–106.6% HL, mean 95.8% vs. 42.7%–98.8%, mean 83.5% in all other subspecies), deep head (HD 57.1%–72.4% HL, mean 63.6% vs. 44.0%–67.2%, mean 57.9% in all other subspecies) and wide head (HW 59.3%–67.7% HL, mean 63.2% vs. 49.1%–66.8%, mean 59.2% in all other subspecies).

Distribution: Known from the Río Madre de Dios in the Madre de Dios Department of Peru, the Río Candamo in Sandia province Peru, and the Río Guaporé in the Santa Cruz department and the Río Mamoré and Río Madeira and Río Beni in the Beni department of Bolivia ( Figure 2 B).

Etymology: Subspecific epithet derived from the Río Madeira.

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.