Laemolyta proxima ( Garman, 1890 )

Mautari, Kelly Cristina & Menezes, Naércio Aquino, 2006, Revision of the South American freshwater fish genus Laemolyta Cope, 1872 (Ostariophysi: Characiformes: Anostomidae), Neotropical Ichthyology 4 (1), pp. 27-44 : 38-41

Laemolyta proxima ( Garman, 1890)

Fig. 19

Anostomus (Schizodontopsis) proximus Garman, 1890: 19 [original description, type locality: Villa Bella and Ueranduba]; Borodin, 1931:47 [diagnosis, MCZ material listed]; Eschmeyer, 1998: 1386 [catalog].

Laemolyta proximus: Eigenmann & Eigenmann, 1891:50 [listed].

Anostomus proximus: Eigenmann, 1910: 425 [listed].

Laemolyta proxima: Myers, 1950: 197 [diagnosis, typelocality]; Fowler, 1950: 209 [synonymy list, distribution]; Géry, 1964: 466 [identification key], 1974:155–157, 159 [diagnosis, description, identification key]; Garavello & Britski, 2003: 73 [catalog].

Anostomus (Laemolyta) proximus: Géry, 1977: 182 [synonymy, identification key, distribution].

Anostomus (Schizodontopsis) varius Garman, 1890: 19 , 20 [original description, type-locality: Gurupa, José Fernandes, Lake Hyanuary, Manaos (Manaus), Obydos (Óbidos), Porto do Moz, rio Negro]; Ulrey, 1895: 261 [morphological data, color pattern]; Borodin, 1931: 46–47 (diagnosis, MCZ material listed]; Eschmeyer, 1998: 1745 [catalog].

Anostomus varians [error]: Eigenmann & Eigenmann, 1891: 425 [listed].

Laemolyta varia: Myers, 1950: 197 [diagnosis, type-locality]; Fowler, 1950: 209 [synonymy list, distribution]; Géry, 1964: 466 (identification key]; 1974: 155–157, 159 [diagnosis, description, identification key]; Santos, 1982: 713–739 [ecological data]; Santos & Jegú, 1996: 161, fig. 11, p. 179 [INPA’s material listed, rio Uatumã (Amazon basin)]; Garavello & Britski, 2003: 73 [catalog].

Anostomus varius: Vari & Howe, 1991: 5 [type catalog].

Anostomus (Schizodontopsis) varius nitens Garman, 1890: 20 [original description, type-locality: Iça]; Borodin, 1931:47 [diagnosis]; Eschmeyer, 1998: 1190 [catalog].

Laemolyta varius nitens: Eigenmann & Eigenmann, 1891: 50 [listed].

Anostomus varians [error] nitens: Eigenmann, 1910: 425 [listed].

Anostomus (Schizodontopsis) nitens: Borodin, 1931: 46–47 [diagnosis, material of MCZ listed)

Laemolyta nitens: Myers, 1950: 197 [diagnosis, type-locality]; Fowler, 1950: 209 [synonymy list, distribution]; Géry, 1964: 466 [identification key]; 1974:155–157, 159 [diagnosis, description, identification key]; Garavello & Britski, 2003: 73 [catalog].

Anostomus (Laemolyta) nitens: Géry, 1977: 182 [identification key, distribution].

Anostomus nitens: Vari & Howe, 1991:5 [type catalog].

Material examined. 244 specimens (48.1–249.9 mm SL). Brazil. Amazonas: Villa Bella ( rio Amazonas at Parintins and environs), 27 August 1865, L. Agassiz, MCZ 19331 , 1 lectotype (designated herein), 165.3 mm SL. Lago José Fernandes (location unknown, presumably near Manaus ), November 1865, Maj. J. M. S., MCZ 19378 , 5 paralectotypes, 75.9–113.1 mm SL. Rio Negro at Manaus , 1863, J. C. Fletcher, MCZ 809 , 1 paralectotype, 160.7 mm SL. Lago Hyanuary (Paraná do Janauari ), 27 October 1865, L. Agassiz, MCZ 19335 , 4 paralectotypes, 98.6–188.1 mm SL. Içá, November, 1865, USNM 120242 , 3 paralectotypes, 82.9–92.5 mm SL. José Fernandes, 1867, USNM 120398 , 1 paralectotype. Mouth of rio Ituxi , MZUSP 21487 , 2 , 168.7 and 174 mm SL. Lagoa Central, left bank of rio Negro , between rivers Camaraú and Apaú, MZUSP 21062 , 3 of 4, 81.4–91.4 mm SL. Lago Janauacá, MZUSP 27898 , 1 , 80.0 mm SL. Lago Puraquequara, rio Amazonas , MZUSP 53640 , 4 , 65.6–83.4 mm SL. Lago Janauarí , MZUSP 62434 , 3 , 76–83.4 mm SL. Lago Manacapuru , MZUSP 5886 , 1 of 2, 224.5 mm SL. Lago Berurí, rio Purus , MZUSP 6003 , 2 , 170.7 and 178.8 mm SL. Rio Negro near Manaus , MZUSP 6703 , 1 , 86.1 mm SL. Rio Madeira , 25 km below Nova Olinda, MZUSP 6964 , 1 , 95.1 mm SL. Rio Canumá , MZUSP 7058 , 2 , 170.8 and 188.9 mm SL. Paraná de Urucará, Urucará , MZUSP 7517 , 3 , 95.6–103.7 mm SL. Mouth of Lake José-Açu , Parintins, MZUSP 7643 , 2 , 99.2–119.9 mm SL. Lago Castro, mouth of rio Purus , MZUSP 20907 , 1, 106.9 mm SL. Rio Negro , Cantagalo, MZUSP 43293 , 1, 228 mm SL. Lago Janauacá, right bank of rio Solimões , MZUSP 21557 , 1, 200.8 mm SL. Lago Janauacá and surroundings, rio Solimões , MZUSP 21693 , 3 , 175.5 – 239.6 mm SL. Costa do Japão, lower rio Japurá , Tefé, MZUSP 27381 , 1, 101.8 mm SL, MZUSP 27382 , 1 , 92 mm SL. Rio Tefé, Mucurá , MZUSP 29186 , 6 , 72.2–97.3 mm SL, MZUSP 60185 , 4 of 7, 188.5– 214.4 mm SL. Rio Negro , Anavilhanas, MZUSP 29191 , 2 , 97.9–100.7 mm SL, MZUSP 32414 , 1, 169.5 mm SL, MZUSP 32415 , 3 , 194.9 – 226.7 mm SL, MZUSP 60176 , 1, 172.9 mm SL, MZUSP 60185 , 4 of 7, 188.5– 214.4 mm SL, MZUSP 60177 , 1, 159.3 mm SL. Rio Tefé, Aranatuba , MZUSP 29187 , 1 of 3, 97 mm SL. Rio Tefé , beach at Vista Escura, MZUSP 31426 , 1, 178.4 mm SL, MZUSP 32403 , 4 of 14, 169.8– 249.9 mm SL Rio Tefé, Mastro, Ressaca, MZUSP 32399 , 1, 208.3 mm SL. Rio Tefé, beach at Jurupari , MZUSP 32400 , 5 , 212.6 – 229.5 mm SL, MZUSP 61458 , 5 , 201.2 – 230.7 . Lake at Tefé , MZUSP 32401 , 8 of 17, 201.3– 239.2 mm SL. Rio Tefé, Mastro, Capim , MZUSP 60171 , 2 , 214.6 – 224.7 . Tefé, beach at Jurupari , MZUSP 60173 , 1, 212.5 mm SL. Rio Tefé, Supiã-Pucu , MZUSP 60174 , 3 , 205.7 – 231.7 mm SL. Rio Tefé, Ressaca de Paula , MZUSP 60179 , 11 of 23, 162.5– 225.6 mm SL. Rio Negro , junction with Ararirá, MZUSP 60188 , 1, 218 mm SL, MZUSP 60189 , 5 , 159.1 – 238.4 mm SL. Pará: Gurupá ( rio Amazonas delta at Gurupá ), 22 August 1865, L. Agassiz et al., MCZ 19340 , 3 paralectotypes, 111.5–126.7 mm SL. Porto Moz, rio Xingu at Porto do Moz , 23 August 1865, L. Agassiz et al., MCZ 19341 , 1 paralectotype, 175.9 mm SL. Rio Amazonas at Óbidos , November 1865, Bento, MCZ 19348 , 2 paralectotypes, 87.8–103.8 mm SL. Óbidos (rio Amazonas at Óbidos ), December 1865, James, W. & W. Hunnewell, MCZ 19532 , 1 paralectotype, 58.1 mm SL. Rio Tapajós, Pimentel, below mouth of rio Jamanxim , INPA 6906 , 3 , 54.0– 65.6 mm SL. Rio Trombetas, lago Jacaré, Expedição do Departamento de Zoologia and Museu Goeldi, MZUSP 64066 , 4 , 117.8 – 132.1 mm SL. Lago Bernardino, near Badajós, rio Capim , MZUSP 6874 , 1 of 2, 101.1 mm SL. Paraná Samuuma, mouth of rio Tocantins , MZUSP 21249 , 2 , 197 – 200.0 mm SL. Igarapé Açu , Aveiro, MZUSP 21360 , 1, 125.3 mm SL. Rio Tapajós, São Luís , MZUSP 21388 , 1 of 2, 191.3 mm SL. Rio Tapajós , Barreirinha, MZUSP 21411 , 1, 178.3 mm SL. Rio Tapajós, Maloquinha , MZUSP 21400 , 2 , 173.3 and 186.1 mm SL. Rio Tapajós , lake in front of Monte Cristo, MZUSP 21414 , 1, 148.4 mm SL. Igapó do lago Farias, rio Trombetas , Trombetas Biological Reserve , MZUSP 15788 , 1, 202.3 mm SL, MZUSP 15960– 61 , 1 200.1 mm SL. Rio Xingu, Belo Monte , river channel, MZUSP 60182 , 5 of 19, 179.5– 194.8 mm SL, MZUSP 61640 , 1 of 2, 192.1 mm SL. Rio Tapajós , between Itaituba and São Luís, MZUSP 61640 , 1 of 2, 192.1 mm SL. Rio Trombetas , 20 km above mouth, MZUSP 61950 , 1, 145.5 mm SL. Roraima: rio Branco , INPA 14046 , 5 , 74.7– 97.2 mm SL. Rio Branco, Marará, Paraná-Fechada , MZUSP 60183 , 2 , 205.2 – 210.6 mm SL. Rio Branco between mouth and rio Xeriuni , MZUSP 61443 , 1, 197.4 mm SL. Rio Branco, beach and Paraná at Marará, MZUSP 61642 , 5 , 149.6 – 191.7 mm SL. Bolivia, Beni: río Baures at mouth on right bank 6 km SW of Costa Marques, AMNH 39987 , 6 , 48.1–143.9 mm SL. Río Itenez, 1 km downstream (W) of Costa Marques , Mamoré-Madeira-Amazon drainage, UMMZ 204904 , 3 , 69.9–187.7 mm SL. Guiana. Essequibo River , Rockstone, ANSP 137804 , 1, 114.8 mm SL. Peru. Loreto: río Nanay , well above Moronacocha, vicinity of Iquitos, ANSP 137804 , 1, 114.8 mm SL. Itaya, Ancieta , UMMZ 216875 , 1 , 96.7 mm SL. Shansho caño, drainage of Ampiyacu, USNM 175839 , 1, 144.9 mm SL. Río Itaya, main channel and portions below caños, 5 to 20 km above Belen, Iquitos , USNM 280741 , 1 , 74 mm SL. Río Nanay , approximately 20 km above mouth, main channel, lateral channels and ponds, USNM 280712 , 3 of 4, 76.8–81.7 mm SL.

Diagnosis. Laemolyta proxima differs from L. garmani and L. taeniata in having more longitudinal rows of scales from the lateral line to the dorsal-fin origin (6–8 vs. 4–5) and also from L. garmani in having more longitudinal rows of scales from the lateral line to the anal-fin origin (5–6 vs. 4). Laemolyta proxima differs from L. orinocensis in having fewer scales along the lateral line (43–47, usually 45 vs. 47–52). Laemolyta proxima has fewer perforated scales along the lateral line than does L. fernandezi (43–47 vs. 49–58).

Description. Meristic and morphometric data presented in Table 5. Body moderately large (SL = 48.1–249.9 mm SL). Dorsal profile of body straight from tip of snout to end of supraoccipital spine, slightly convex from that point to origin of dorsal fin, straight and posteroventrally-inclined along dorsal-fin base and straight and posteroventrally-inclined or slightly convex from posterior margin of dorsal-fin base to caudal peduncle. Ventral profile of body almost straight from tip of lower jaw to region near isthmus, slightly convex from that point to origin of anal fin, and slightly concave at insertion of pelvic fins.

Gill rakers on dorsal limb of first branchial arch 9–12 and 10–14 on lower limb.

Perforated scales on lateral line 43–47 (46*, usually 45, Table 2). Longitudinal scale rows from lateral line to dorsalfin origin 6–8 (6*, usually 6); scales rows from lateral line to anal fin origin 5–6 (5*, usually 5). Predorsal scales irregularly arranged. Scales rows around caudal peduncle 16 (16*).

Dorsal-fin rays ii–iii,10–12 (11*, usually 11); distal margin of fin convex. Anal fin short, slightly falcate, with i–ii,8 rays. Pectoral fin rays i,11–16 (13*, usually 13). Pelvic fin rays i,7– 9 (8*, usually 8); distal margin of fin truncate. Vertebrae 41–42 (42*, usually 42, N=5).

Color in alcohol. Dorsal region of body of adult specimens ( Fig. 20 ) generally dark, extending ventrally to within 1–1.5 longitudinal scale rows above lateral line. Sometimes inconspicuous dark midlateral longitudinal stripe, covering 1.5 to 2

40 Revision of the South American Anostomid genus Laemolyta longitudinal scale rows extending from tip of snout to rear of caudal peduncle. Stripe ends in form of triangular or ovalshaped dark spot. Ventral part of body lighter from lower limit of longitudinal dark stripe to midlateral line. Four vertical dark bars sometimes crossing body, first located between opercle and dorsal fin nearer to opercle, second under dorsal fin, third between pelvic and anal fins, and fourth anterior to vertical through base of adipose fin. Young specimens with highly variable number of narrow, transverse, dark bars (up to 26) extending from dorsal margin of body to near lateral line. Dorsal, pectoral, pelvic and caudal fins hyaline. Anal and adipose fins with scattered dark chromatophores.

Several specimens from the rio Tapajós have the body coloration very light with the dorsum dark and the remaining parts of body almost entirely silvery. Santos (1982) examined young specimens (up to 70 mm SL) bearing 12 to 16 dark, vertical bars on the dorsal part of the body. According to author, specimens longer than 70 mm SL tend to loose most of these bars, with only those which form the four bars found in adult specimens retained. In the present study 14 to 26 dark, vertical bars were found in specimens smaller than 88 mm SL, with most having 14 to 16 bars. Other specimens did not show any dark bars or spots on the body probably due to the method of preservation. In some other individuals, only the longitudinal stripe ( Fig. 21) and the transverse, dark bars or oval-shaped spots over the inconspicuous longitudinal stripe ( Fig. 22 ) were visible.

Distribution. Amazon basin ( Peru and Brazil) and Essequibo River in Guiana ( Fig. 13 ).

Remarks. Laemolyta proxima was described by Garman (1890) as Anostomus (Schizodontopsis) proximus together with A. (Schizodontopsis) varius and A. (Schizodontopsis) nitens . These three species were recognized as distinct by Borodin (1931) who, nonetheless, considered the first A. proximus and A. varius to be very similar on the basis of their body shape and color pattern, and with A. nitens very similar to A. varius but having the body more elongate and with an overall lighter coloration.

Géry (1974) considered these three species as part of a complex and divided that into two units: the proxima-varia group, which was characterized by the presence of a dark, midlateral longitudinal stripe and nitens , which had dark spots over an inconspicuous dark longitudinal stripe, a larger orbital diameter, and the body more elongate. In the same paper, Géry cast doubts on the recognition of two different species within the first group. The same author (1977) included Laemolyta as a subgenus of Anostomus , considered L. nitens to be a valid species and provided an identification key which suggested that Anostomus (Laemolyta) proximus is a synonym of Anostomus (Laemolyta) varius .

According to Garman (1890) Laemolyta proxima would be closely related to L. taeniata from which it could be distinguished in having smaller and consequently more numerous scales. Indeed some of the examined specimens of L. proxima species have a color pattern identical to that of L. taeniata , but the differences in scale counts make their identification possible.

Notwithstanding the differences in color pattern and number of scales between Laemolyta varia and L. proxima reported by Garman (1890), an examination of the syntypes of L. varia indicated that these characters fall within the range of variation found in L. proxima . The two species are, thus, considered synonymous, with L. proxima utilized because it appears first in Garman’s publication.

The color pattern described by Garman (1890) to characterize Laemolyta nitens dark longitudinal stripe, dark spots along the lateral line, and the presence in some specimens of narrow, dark, vertical bars and faint dark spot on the caudal peduncle also occurs in some specimens of L. proxima ( Fig. 22 ). This, however, falls within the color pattern variation in this species. The comparison of meristic and morphometric data between the two nominal species failed to reveal any significant difference, and L. nitens is, thus, placed as a junior synonym of L. proxima .

Lasso (1992) reported Laemolyta proxima from the río Suapare (tributary of the río Orinoco, Venezuela). Two out of the 3 specimens in the lot that served as the basis of that record (MHNLS 5512) were examined. One specimen proved to be L. taeniata and the other L. orinocensis . The third specimen, probably the one illustrated in the paper, also looks very much like L. taeniata , because of the clearly visible dark longitudinal stripe, and the whitish areas on the scales above the lateral line that form forming light stripes and which are characteristic of this species.

Data from Santos & Jégu (1996) indicate that Laemolyta proxima is found in floodplain lakes in large shoals during certain parts of the year, sometimes occurring together with L. garmani . Those authors note that L. proxima is fished commercially. The species is omnivorous, but feeds mainly on insect larvae and vegetable material ( Santos, 1982). It is widely distributed through the Amazon Basin including Peru.

In the original description several specimens were designated syntypes of Anostomus (Schizodontopsis) proxima . The specimen in MCZ 19331 was examined and is herein designated as the lectotype .

Figures

Fig. 19. Laemolyta proxima, MCZ 19331, lectotype, 165.3 mm SL; Brazil,Amazonas, rio Amazonas, Vila Bela, Parintins.

Fig. 20. Adult specimen of Laemolyta proxima, MZUSP 61642, 180.3 mm SL; Brazil, Roraima, rio Branco, Marará, Paraná-praia.

Fig. 22. Young specimen of Laemolyta proxima, MZUSP 27382, 92 mm SL; Brazil,Amazonas, Costa do Japão, Ressaca do Japão, lower rio Japurá.

Fig. 13. Geographic distribution of Laemolyta proxima (black dots; open circle = type-locality), Laemolyta garmani (black squares; open squares = type-locality), and Laemolyta orinocensis (black triangles; open triangle = type-locality). Some symbols might correspond to more than one locality.