Neoplecostomus langeanii, Roxo, Fábio F., Oliveira, Claudio & Zawadzki, Cláudio H., 2012

Roxo, Fábio F., Oliveira, Claudio & Zawadzki, Cláudio H., 2012, Three new species of Neoplecostomus (Teleostei: Siluriformes: Loricariidae) from the Upper Rio Paraná basin of southeastern Brazil, Zootaxa 3233, pp. 1-21 : 12-15

Neoplecostomus langeanii , new species

Figure 8 , Table 1.

Neoplecostomus sp. 2. Reusing et al. (2011): 497 [photo; Figure 1 b compares this species with Neoplecostomus sp. 1]

Holotype: MZUSP 110365 (1 male, 85.5 mm SL), Brazil, Minas Gerais state, municipality of Muzambinho, Rio São Domingos, tributary of Rio Muzambinho, Rio Grande basin, 21°23’22”S 46°28’40”W, 7 Jan 2008, F. F. Roxo, J. M. Henriques, G. J. Costa e Silva, L. H. G. Pereira.

Paratypes: All paratypes are from Minas Gerais state in Brazil, in the municipality of Muzambinho, Rio Muzambinho, Rio Grande basin. DZSJRP 14882 (6 females, 44.8–63.9 mm SL) 21°19’36”S 46°27’27”W, 10 Jan 2008, F. F. Roxo et al. DZSJRP 14880 (2 males, 69.0– 70.6 mm SL) 21°23’22”S 46°28’40”W, 7 Jan 2008, F. F. Roxo et al. LBP 5870 (17 unsexed, 33.4–63.3 mm SL); 21°20’47”S 46°28’08”W, 9 Jan 2008, F. F. Roxo et al. LBP 5873 (1 unsexed, 37.9 mm SL); 21°19’36”S 46°27’27”W, 9 Jan 2008, F. F. Roxo et al. LBP 5878 (2 males, 53.1– 84.5 mm SL; 7 females, 48.6–70.7 mm SL); 21°23’53”S 46°28’45”W, 9 Jan 2008, F. F. Roxo et al. LBP 5886 (3 males, 52.9–58.9 mm SL; 7 females, 39.0– 64.7 mm SL; 11 unsexed, not measured); 21°18’08”S 46°28’33”W, 9 Jan 2008, F. F. Roxo et al. LBP 5901 (2 males, 61.3–65.0 mm SL; 1 male, not measured; 5 females, 54.2–62.9 mm SL; 4 females, not measured); 21°17’37”S 46°29’06”W, 11 Jan 2008, F. F. Roxo et al. (GenBank numbers GQ214799 and GQ214800 ). LBP 5915 (1 male, 68.3 mm SL, 1 unsexed, not measured); 21°21’33”S 46°28’32”W, 8 Jan 2008, F. F. Roxo et al. LBP 5926 (1 male, 89.2 mm SL; 3 females, 34.6–64.5 mm SL); 21°19’59”S 46°27’24”W, 10 Jan 2008, F. F. Roxo et al. LBP 5931 (4 males, 51.8–69.6 mm SL; 7 females, 48.4–62.8 mm SL; 8 unsexed, not measured); 21°23’22”S 46°28’40”W, 7 Jan 2008, F. F. Roxo et al. LBP 5942 (1 female, 40.9 mm SL), 21°22’48”S 46°28’29”W, 8 Jan 2008, F. F. Roxo et al. LBP 5947 (2 males, 71.6–73.5 mm SL; 6 females, 56.6–67.6 mm SL;

27 unsexed, not measured); 21°19’36”S 46°27’27”W, 10 Jan 2008, F. F. Roxo et al. LBP 5961 (10 females, 37.5– 46.3 mm SL; 6 unsexed, not measured); 21°22’48”S 46°28’29”W, 8 Jan 2008, F. F. Roxo et al. LBP 6142 (2 males, 42.2–45.7 mm SL; 7 females, 38.1–49.2 mm SL); 21°24’12”S 46°34’33”W, 15 Apr 2008, F. F. Roxo et al. LBP 6150 (2 males, 43.0– 60.5 mm SL; 2 females, 41.0– 43.2 mm SL), 21°22’43”S 46°33’21”W, 15 Apr 2008, F. F. Roxo et al. LBP 6155 (11 unsexed, not measured); 21°23’49”S 46°33’17”W, 15 Apr 2008, F. F. Roxo et al. LBP 6160 (3 unsexed, not measured) 21°23’04”S 46°32’22”W, 16 Apr 2008, F. F. Roxo et al. LBP 6173 (5 females, 39.7–47.0 mm SL); 21°21’41”S 46°34’36”W, 16 Apr 2008, F. F. Roxo et al. (GenBank number GQ214801 ). LBP 6179 (4 males, not measured; 1 female, not measured; 5 unsexed, not measured); 21°21’40”S 46°33’22”W, 16 Apr 2008, F. F. Roxo et al. LBP 6183 (1 male, 44.4 mm SL); 21°22’13”S 46°32’11”W, 16 Apr 2008, F. F. Roxo et al. LBP 6195 (1 male, 68.0 mm SL; 5 females, 35.1–68.0 mm SL; 1 unsexed, not measured), 21°22’15”S 46°32’35”W, 18 Apr 2008, F. F. Roxo et al. (GenBank numbers GQ214797 and GQ214798 ). LBP 6210 (1 unsexed, not measured). 21º23’31”S 46º30’11”W, 18 Apr 2008, F. F. Roxo et al. LBP 6244 (3 males, 68.7–79.0 mm SL); 21°19’44”S 46°30’04”W, 19 Apr 2008, F. F. Roxo et al. MZUSP 110361 (1 male, 83.4 mm SL); 21°17’37”S 46°29’06”W, 11 Jan 2008, F. F. Roxo et al. MZUSP 110360 (1 male, 54.0 mm SL; 5 females, 46.0– 55.5 mm SL); 21°19’36”S 46°27’27”W, 10 Jan 2008, F. F. Roxo et al. NUP 6102 (2 males, not measured; 5 females, not measured) 21°20’47”S 46°28’08”W, 9 Mar 2008, F. F. Roxo et al. NUP 11988 (1 male, 85.5 mm SL) 21º17’37”S 46º29’06”W, 11 Jan 2008, F. F. Roxo et al.

Diagnosis: Neoplecostomus langeanii differs from N. bandeirante by the absence of keels along each lateral series of plates (vs. presence of moderate keels). Neoplecostomus langeanii differs from N. botucatu and N. paranensis , by having a well-developed adipose fin (vs. adipose fin reduced or absent). Neoplecostomus langeanii differs from N. franciscoensis and N. ribeirensis , by having a dorsal-fin spinelet larger than dorsal-fin spine (vs. dorsal-fin spinelet absent to vestigial and more slender than dorsal-fin spine). Neoplecostomus langeanii differs from N. granosus , N. microps , and N. variipictus by the presence of five conspicuous dark bands on dorsum and lacking evident dark spots (vs. conspicuous dark spots all over body and fins and dorsal bands not evident) characteristics that are more evident in mature adults. Neoplecostomus langeanii is distinguished from N. selenae by lacking enlarged odontodes and a distinct, swollen integument along lateral margins of snout and along ridges anterior to eyes (vs. having enlarged odontodes and distinct swollen integument along lateral margins of snout and along ridges anterior to eyes). Neoplecostomus langeanii is distinguished from N. corumba by having smaller orbital diameter 8.3- 11.4% in head length, 12.9–18.5% in snout length, and 27.0–35.7% in interorbital length (vs. 12.2–13.05%, 18.4– 20.1%, and 36.7–41.5%, respectively); from N. yapo , by having a smaller interdorsal length, ranging from 14.8– 19.5% in SL (vs. 20.7–23.0%), greater caudal peduncle depth 19.8–29.0% in caudal peduncle length (vs. 17.6– 19.6%), smaller orbital diameter 8.3–11.4% in head length (vs. 11.9–21.4%); from N. espiritosantensis , by having greater cleithral width 25.6–30.0% in SL (vs. 19.0–21.0%).

Description: Counts and measurements are presented in Table 1. Body elongated and depressed; greatest width at cleithrum, narrowing to caudal peduncle. Dorsal body profile gently convex, elevating from snout tip to dorsal-fin origin and descending to first caudal-fin procurrent ray. Greatest body depth at dorsal-fin origin; trunk and caudal peduncle dorsally rounded in cross-section. Body ventrally flattened to anal-fin origin, flattened to slightly rounded to caudal fin. Dorsal body surface completely covered by dermal plates, excepting for a naked area around dorsal-fin base. Snout tip with a small naked area.

Ventral head surface naked except for one plate bearing odontodes in front of gill openings; abdomen with conspicuous, small dermal platelets between insertions of pectoral and pelvic fins, forming a thoracic shield surrounded by naked areas; in some specimens some isolated platelets are present near pectoral-fin base. Head wide and depressed; head and snout rounded in dorsal view; interorbital space straight to slightly concave in frontal view; slight median ridge formed by the mesethmoid rising from snout tip to area between nares, not evident in some specimens. Weak ridge from nares to superior margin of orbit; snout gently convex in lateral profile; mature males with moderately enlarged boomerang-like (curved backward) odontodes, from snout tip to post-orbital region. Hypertrophied odontodes not surrounded by distinct swollen skin along dorsal and ventral lateral margin of snout. Eye moderately small (8.3–11.4% of HL), dorsolaterally placed. Lips well developed and rounded; lower lip not reaching pectoral girdle and covered with papillae, wider anteriorly; two or three irregular and conspicuous rows of large and transversally flattened papillae, just posterior to dentary teeth; posterior row of papillae distributed along entire dentary ramus. Maxillary barbel short and coalesced with lower lip; its tip not free from lower lip. Teeth long, slender and bicuspid; mesial cusp longer than lateral; dentary ramus forming an angle of approximately 125–130º.

Dorsal-fin origin slightly posterior to vertical passing through pelvic-fin origin; nuchal plate not covered by skin; dorsal-fin spinelet short and wider than dorsal-fin spine base; dorsal-fin locking mechanism absent; dorsal-fin with one flexible spine, followed by seven branched rays; its posterior margin straight or slightly furcate, not reaching the end of pelvic-fin rays when adpressed. Well-developed and always present adipose fin, not preceded by azygous plate. Pectoral fin with one spine and six branched rays; spine depressed and curved inward (more curved in larger specimens), shorter than longest branched ray; its posterior margin emarginate, reaching about half pelvicfin unbranched ray length when adpressed. Pelvic fin with one unbranched ray and five branched rays; its posterior margin straight to nearly straight, surpassing anal-fin insertion when adpressed. Pelvic-fin unbranched ray ventrally flattened, with dermal flap on its dorsal surface in males. Anal fin with one flexible unbranched ray and five branched rays; its posterior margin slight emarginated to straight. Caudal fin furcate; lower lobe slightly longer than upper; 14 branched rays. Pectoral spine and pelvic-fin unbranched ray with odontodes on lateral and ventral portions; anal-fin unbranched ray with odontodes only ventrally.

Color in alcohol: color of dorsal surface of head and body yellowish. Dorsal color pattern, even in mature larger individuals, retains the generic juvenile color pattern of five transverse dark bands: the first through supraoccipital, the second anterior to dorsal fin, the third posterior to dorsal fin, the fourth at adipose fin, and the last at caudal-peduncle posterior portion. Head usually with two clear, short and parallel inconspicuous lines anterior to nares, bordering the naked area on snout tip. Orbital margin slightly lighter, mainly on its superior portion; small pale spot on interorbital space, inconspicuous in some specimens.

Lateral portion of body with upper darker region and lower lighter one, just below lateral line, not easily visualized in large specimens. Dorsal fin with irregular series of dark marks or bands on rays. Caudal fin with two to three faded and irregular dark bands at base, at middle portion, and at distal portion of rays, leaving two interspaced lighter areas among dark bands. Pectoral, pelvic, and anal fins with dark marks forming irregular bands, usually diffuse. Adipose fin generally dark on spine and pale on the membrane portion. Ventral surface of head and body mostly depigmented, except on lateral body margins and from pelvic fin to caudal-fin base. Upper lip dark brown, except for its light narrow margin.

Sexual dimorphism: Mature males have a papilla in the cloaca and a slender membrane in the pelvic fin. Both characteristics are absent in females ( Figure 4 ).

Distribution: The species is found in the drainages of Rio Muzambinho in the municipality of Muzambinho, Minas Gerais state, Brazil ( Figure 5 ).

Etymology: The specific name, langeanii , is in honor of researcher Francisco Langeani Neto from Universidade Estadual Paulista (UNESP), Instituto de Biociências, Letras e Ciência Exatas, in recognition of his dedication and contributions to the study of Neotropical fishes.

Figures

FIGURE 1. Neoplecostomus bandeirante, MZUSP 110363, (male) SL = 109.9 mm, holotype from Rio Paraitinguinha in the municipality of Salesópolis.

FIGURE 4. Sexual dimorphism in Neoplecostomus species. (a) Dorsal view of a male Neoplecostomus botucatu, MZUSP 110362, 84.3 mm SL; (b) Picture corresponding to the highlighted area in (a) showing the membrane in the pelvic fin; (c) Ventral view of a male Neoplecostomus botucatu, MZUSP 110362, 84.3 mm SL; (d) Picture corresponding to the highlighted area in (c) showing the urogenital papilla; (e) Dorsal view of a female Neoplecostomus botucatu, LBP 8065, 75.3 mm SL; (f) Picture corresponding to the highlighted area in (e) showing the absence of a membrane in the pelvic fin; (g) Ventral view of a female Neoplecostomus botucatu, LBP 8065, 75.3 mm SL; (h) Picture corresponding to the highlighted area in (g) showing the absence of a urogenital papilla. Scale bars = 1 mm.

FIGURE 5. Distribution of Neoplecostomus samples used in the molecular analysis. Yellow triangles refer to the former, nominal species and red triangles refer to the new species. The geographic position is shown in the Table 2.

FIGURE 8. Neoplecostomus langeanii, MZUSP 110365, (male), SL = 85.05 mm, holotype from Rio Muzambinho drainages in Muzambinho municipality.