Laemolyta fernandezi ( Myers, 1950 )

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: 31-33

publication ID

http://doi.org/ 10.1590/S1679-62252006000100002

publication LSID

lsid:zoobank.org:pub:22071950-40B5-4151-AB3C-D6AE6A2607E9

persistent identifier

http://treatment.plazi.org/id/038187AC-9965-FC41-FEFF-F99DFAC2850C

treatment provided by

Carolina

scientific name

Laemolyta fernandezi ( Myers, 1950 )
status

 

Laemolyta fernandezi ( Myers, 1950)  

Fig. 4 View Fig

Laemolyta fernandezi Myers, 1950: 197   , 198, [original description, type locality: upper Orinoco]; Géry, 1964: 466 [key to species]; Géry, 1974: 157–159, Fig. (3), p. 158 [complementary description, key to species]; Böhlke, 1953: 197 [catalog of types]; Eschmeyer, 1998: 574 [catalog]; Garavello & Britski, 2003: 73 [catalog]; Taphorn et al., 1997:55–100 [catalog]; Lasso et al., 2004:105–195 [list of species and distribution].

Laemolyta petiti Géry, 1964: 464   , plate IV b [type locality: ilha do Bananal, upper rio Araguaia]; Santos & Jégu, 1989: 166, Fig. p. 196 [redescription]; Santos et al., 1984: 33 [lower rio Tocantins]; Eschmeyer, 1998: 1326 [catalog]; Garavello & Britski, 2003: 73 [catalog].

Anostomus (Laemolyta) fernandezi: Géry, 1977: 180   [key to species, distribution].

Material examined. 93 specimens (63.6–212.9 mm SL). Venezuela. Río Orinoco system, upper Orinoco, 1925, C. Ternetz, CAS 116126 View Materials , holotype, 73.1 mm SL. Anzoategui, río Orinoco basin, ANSP 166730 View Materials , 5 View Materials , 80.2–152.6 mm SL. Bolivar, río Orinoco basin, San Pedro de Tauca , ANSP 166532 View Materials , 1 View Materials , 137.0 mm SL. Bolivar, laguna Aricagua , floodplain, río Caura , Vispo Conrad , MHNLS 13061 View Materials , 1 View Materials of 2, 110.9 mm SL. Bolivar, laguna Guaiparo , San Felix , MHNLS 7063 View Materials , 1 View Materials of 3, 102.6 mm SL. Delta Amacuro, caño Guarguapo , in small tributary, approximately 500 m from mouth in río Orinoco , MZUSP 62448 View Materials , 2 View Materials , 80.6–109.8 mm SL. Brazil. Tocantins: upper rio Araguaia , ilha do Bananal , MHNG 2229.01 View Materials , 1 View Materials , 74.8 mm SL. Pará: Itupiranga , Tocantins, INPA 1546 View Materials , 4 View Materials , 136.1 View Materials – 166.6 mm SL, INPA 1548 View Materials , 5 View Materials , 137.8 View Materials – 156.7 mm SL, INPA 1888 View Materials , 1, 141.5 mm SL. Rio Tocantins, Icangui , Projeto Tucuruí , INPA 1547 View Materials , 7 View Materials , 95.1 View Materials 141.7 View Materials , INPA 12234 View Materials , 14 View Materials , 81.8–136.5 mm SL, INPA 15350 View Materials , 6 View Materials , 110.8 View Materials – 162.2 mm SL. Rio Tocantins below dam, Tucuruí , INPA 1549 View Materials , 4 View Materials , 168.3 View Materials – 191.1 mm SL, INPA 16176 View Materials , 2 View Materials , 134.1 View Materials – 164.2 mm SL. Rio Tocantins, poço do Paulo , below Tucuruí Dam , INPA 1889 View Materials , 2 View Materials , 87.5–89.3 mm SL. Rio Tocantins, Jatobal , above Tucuruí Dam , INPA 1890 View Materials , 2 View Materials , 183.2 View Materials – 183.8 mm SL. Rio Tocantins, Tucuruí market, INPA 1891 View Materials , 2 View Materials , 193.4 View Materials – 201.3 mm SL. Rio Tocantins, INPA 15295 View Materials , 2 View Materials , 152.9 View Materials – 191.3 mm SL. Rio Tocantins, reservoir above Tucuruí Dam , INPA 16176 View Materials , 2 View Materials , 134.1 View Materials and 164.2. Rio Tocantins, lago Tauá below Tucuruí , INPA 16177 View Materials , 7 View Materials , 132.5 View Materials – 156.3 mm SL. Base I of Tucuruí reservoir, INPA 16178 View Materials , 5 View Materials , 161.7 View Materials – 193.7 mm SL. Base IV of Tucuruí reservoir, INPA 16179 View Materials , 2 View Materials , 198.3 View Materials – 208.7 mm SL. Rio Xingu , Belo Monte , MZUSP 60180 View Materials , 3 View Materials , 172.8 View Materials – 212.9 mm SL, MZUSP 60181 View Materials , 4 View Materials , 163 View Materials – 178.7 mm SL. MZUSP 61947 View Materials , 1, 164.9 mm SL. Mato Grosso: rio Araguaia , Santa Terezinha , MZUSP 20842 View Materials , 7 View Materials , 63.6–110.3 mm SL   .

Diagnosis. Laemolyta fernandezi   is distinguished from all congeners by its deeper body (22.9–31.6 % vs. 17.2–29.8 %, respectively, Fig. 5 View Fig ). It can be further distinguished from all Laemolyta species   , except L. orinocensis   , by having more lateral line scales (49–58 vs. 40–47). Although L. fernandezi   cannot be separated from L. orinocensis   on the basis of this character, the latter species has a very conspicuous midlateral dark stripe, whereas in L. fernandezi   this stripe is inconspicuous and the transverse dark spots are much more evident than in L. orinocensis   .

Description. Morphometric and meristic data presented in Table 1. Body moderately large (SL = 63.6–212.9 mm). Dorsal profile of body straight or slightly concave from snout tip to end of supraoccipital spine, slightly convex from that point to origin of dorsal fin, straight and posteroventrally aligned along dorsal-fin base and straight or slightly convex from base of posterior most dorsal-fin ray to caudal peduncle. Ventral profile of body straight or slightly convex from anterior tip of lower jaw to region near isthmus and slightly convex from that point to anal-fin origin and slightly concave at region of pelvic-fin insertion. Upper limb gill-rakers 9–12 on first gill arch and 11–15 on lower limb.

Scales small, 49–58 (51*, usually 53, Table 2) perforated along all of lateral line. Longitudinal scale rows from lateral line to dorsal-fin origin 7–8 (8*, usually 8), scale rows from lateral line to anal-fin origin 5–7 (7*, usually 6). Predorsal scales irregularly arranged. Scales rows around caudal peduncle 17–20 (19*, usually 18).

Dorsal fin rays ii,10–12 (10*, usually 11); distal margin of fin slightly rounded. Anal fin short, slightly falcate, with ii–iii (iii, rarely),8–10 (8*, rarely 10) rays. Pectoral fin rays i,11–15 (14*, usually 14). Pelvic fin rays i,8; distal margin of fin truncate. Vertebrae 39–42 (42*, usually 39, N=30).

Color in alcohol.Adult specimens usually with dark, but sometimes very inconspicuous, longitudinal stripe, covering 1.5

to almost 3 longitudinal scale rows. Stripe extends from posterior region of opercle to caudal peduncle where it usually ends in form of darker triangular or oval spot. Upper region of body usually dark, with dark coloration extending ventrally to below midlateral dark stripe. Ventral region of body unpigmented from ventral limit of dark midlateral stripe on body to midventral one. Body with 4 transverse dark but sometimes inconspicuous bars or blotches, sometimes inconspicuous. First series situated between opercle and dorsal fin, but closer to opercle; second below dorsal fin, and usually more conspicuous; third located between pelvic and anal fins and last, anterior to adipose fin. First and second series usually more conspicuous and last series usually diffuse ( Fig. 6 View Fig ).

Young specimens ( Fig. 7 View Fig ) with midlateral longitudinal stripe indistinct, extending from anterior part of snout to rear of caudal peduncle and usually finishing in form of triangular spot. Four transverse bars or blotches present in adults absent. Upper part of body sometimes with approximately 14 narrow transverse dark bars extending ventrally to near lateral line. Adult specimens sometimes retain faded transverse bars. Adult specimens from río Orinoco basin ( Fig. 8 View Fig ) with bars faded and midlateral longitudinal stripe on body very conspicuous.

Dorsal, pectoral, and ventral fins hyaline with scattered dark chromatophores. Dark chromatophores also scattered along fin margin and over median rays of caudal fin. Adipose fin usually dark.

Some specimens with 4 transverse dark bars quite evident, with dark blotch present on caudal peduncle and dark midlateral stripe on body faded ( Fig. 9 View Fig ).

Common name: Venezuela: Mije ( Lasso, 1992).

Distribution: Río Orinoco and Amazon basin (rios Xingu, Tocantins and Araguaia) ( Fig. 10 View Fig ).

Remarks. Laemolyta fernandezi Myers, 1950   , was described based on a young specimen (73.1 mm SL), that was considered to be a new species in having a compressed body and more longitudinal scale rows (8/7) than L. garmani   , L. proxima   and L. taeniata   (4–6/4–7). According to Myers the specimen was collected in the upper río Orinoco, but the precise locality was not provided.

The description of L. petiti Géry, 1964   , is also based on a young specimen (76.4 mm SL), collected in the rio Araguaia. When Géry (1964) described his new species he recognized its similarity with L. fernandezi   , but noted that a comparison between the two nominal forms was impossible because of the succinct description and lack of illustration of L. fernandezi   . Later on Géry (1974) redescribed L. fernandezi   and compared the data he obtained with those of L. petiti   and found that L. fernandezi   has fewer longitudinal scale rows (7–7 ½ / 6–6 ½), more lateral line scales (55) and a deeper caudal-peduncle than did L. petiti   .

The comparison of meristic and morphometric data among specimens of L. fernandezi   from the Orinoco, Tocantins / Araguaia and rio Xingu basins revealed no significant differences between these populations. The number of vertebrae in a sample from the río Orinoco is 41 (10 specimens) and 42 (1 specimen - holotype) and from the rios Tocantins /Araguaia 39 (15 specimens), 40 (3 specimens) and 41 (1 specimen). The number of vertebrae in 4 specimens from the rio Xingu basin is 39 (1 specimen), 40 (2 specimens) and 41 (1 specimen). The comparison of body depth, that seemed to be visually different among the populations originating from the three basins mentioned, also did not show any significant difference ( Fig. 11 View Fig )   .

In spite of the slight difference in number of vertebrae we prefer to recognize just one widely distributed species represented by allopatric populations, especially because no other meristic or morphometric differences were found to distinguish the populations.

Laemolyta fernandezi   was recorded from the rios Tocantins and Araguaia by Santos & Jégu (1989) and is the most common anostomid species in the lower rio Tocantins ( Santos et al., 1984). It is to date the only species of Laemolyta   found in the central portion of the rio Araguaia basin. In the lower rio Araguaia it occurs in sympatry with L. garmani   .

Laemolyta fernandezi   reaches 25 cm SL and eats small invertebrates (Santos & Jegú, 1989), vegetable material and periphiton ( Santos et al., 1984). Sexual maturity seems to occur in specimens at approximately 130 mm SL judging from direct observation of the gonads. Reproduction seems to occur during the flood season ( Santos et al., 1984).

Kingdom

Animalia

Phylum

Chordata

Class

Actinopterygii

Order

Characiformes

Family

Anostomidae

Genus

Laemolyta

Loc

Laemolyta fernandezi ( Myers, 1950 )

Mautari, Kelly Cristina & Menezes, Naércio Aquino 2006
2006
Loc

Anostomus (Laemolyta) fernandezi: Géry, 1977: 180

Gery, J 1977: 180
1977
Loc

Laemolyta petiti Géry, 1964: 464

Eschmeyer, W 1998: 1326
Santos, G 1984: 33
Gery, J 1964: 464
1964
Loc

Laemolyta fernandezi

Lasso, C & Lew, D & Taphorn, C & do Nascimiento, O & Alcala, F 2004: 105
Eschmeyer, W 1998: 574
Taphorn, D & Royero, A 1997: 55
Gery, J 1974: 157
Gery, J 1964: 466
Bohlke, J 1953: 197
Myers, G 1950: 197
1950