Microglanis leniceae, Shibatta, 2016

Shibatta, Oscar Akio, 2016, A new species of bumblebee catfish of the genus Microglanis (Siluriformes: Pseudopimelodidae) from the upper rio Paraguay basin, Brazil, Neotropical Ichthyology (Neotrop. Ichthyol.) 14 (3), No. e 160031, pp. 1-7 : 2-5

Microglanis leniceae , new species

urn:lsid:zoobank.org:act:2566F7BE-D279-4012-816D-8C43ACF4C570

Figs. 1 - 2

Holotype. ZUFMS 4148 , 33.0 mm SL, Brazil, Mato Grosso do Sul, Miranda, upper rio Paraguay basin, rio Betione , 20 o 25’25”S 56 o 23’57” W, 18 May 2013, H. Gimenes Jr.

Paratypes. Brazil, Mato Grosso do Sul: ZUFMS 4143 , 1 , 30.1 mm SL, same data as holotype. Mato Grosso: INPA 27582 , 4 , 19.5 -21.0 mm SL, Araputanga, rio das Pitas, 16 o 09’45”S 58 o 00’05”W, 28 Ago 1984 , V. Py-Daniel. NUP 3533, 1, 29.1 mm SL, Santo Antônio do Leverger, Barão de Melgaço , upper rio Paraguay basin, rio Cuiabá , 15 o 58’S 55 o 56’W, 20 Jan 2003 .

Diagnosis. Microglanis leniceae differs from all congeners, except M. lundbergi Jarduli & Shibatta, 2013 , by the deeply forked caudal fin with pointed lobes, a character invariable even in small specimens (vs. emarginated, rounded, or bifurcated with rounded lobes). Differs from M. lundbergi , by lateral line canal surpassing vertical through end of dorsal fin (vs. not surpassing), 8 to 11 pores on lateral line (vs. 6 to 8), larger dorsal-fin spine length (15.1-17.8% vs. 11.4-15.9% SL), larger predorsal length (38.0-39.5% vs. 35.5-38.6% SL), larger interobital width (44.1-51.2% vs. 40.4-44.2% HL), and larger mouth width (61.5-72.0% vs. 38.0-47.3% HL). Differs from M. cottoides , another species mentioned to the upper rio Paraguay basin, and M. carlae , the species from lower rio Paraguai basin, by the bifurcated hook on anterior margin of pectoral-fin spine (vs. antrorse and retrorse only).

Description. Morphometric data are presented in Table 1. Body depressed from snout to dorsal-fin origin; posteriorly compressed. Dorsal profile slightly oblique upward from snout tip to posterior nostril; slightly convex from posterior nostril to nape; slightly oblique from nape to dorsal-fin origin. Profile from dorsal-fin origin to end of adipose-fin base almost straight (not considering adipose fin), oblique downward. Dorsal profile straighter on small specimens. Ventral profile from tip of lower jaw to end of anal-fin base slightly convex, almost straight. Head large, wider than deep. Mouth terminal, slightly prognathous. Opercular membrane large, well developed. Eye relatively small, covered by skin. Anterior nostril tubular, on superior lips. Posterior nostril rounded, membranous flap on posterior margin, near to eye than to anterior nostril. Maxillary and outer mental barbels slightly surpassing pectoral fin base.

Dorsal fin trapezoidal; posterior border rounded; origin anterior to standard length midpoint; not reaching adiposefin origin when adpressed; first lepidotrichium (“spinelet”) small and rigid, forming dorsal-fin locking mechanism; second ray forming spine, smooth on anterior and posterior margin; I, 6*(6). Adipose fin slightly elongated, posterior border angular and free. Pectoral fin triangular, not reaching pelvic-fin origin when adpressed; first ray rigid, pointed, flattened, slightly arched, strongly serrated on both sides, bifurcated hook between antrorses (distal) and retrorses (proximal) hooks on anterior margin; retrorses hooks on posterior margin ( Fig. 2 ); I, 5*(6). Specimens larger than 21.0 mm SL: retrorses hooks on anterior margin 8*(2) to 9(1); bifurcated hook 0(1) to 1*(2); antrorses hooks 3*(2) or 7(1); small hooks, straight, near tip 0(1), 1(1), 2*(1); retrorses hooks on posterior margin 7*(1) or 10(2). Specimens smaller than 21.0 mm SL: retrorses hooks, proximal 9(2); smaller and straight hooks, distal 2(2) on anterior margin; retrorses hooks on posterior margin 6(1) or 7(1). Pelvic fin rounded, originating just posterior to vertical through end of dorsalfin base, not reaching anal-fin origin when adpressed; i, 5*(6). Anal fin distal profile rounded; anal-fin base length slightly smaller than adipose-fin base; iii, 6*(5)/iv, 5(1). Caudal fin deeply forked; lobes distal profiles pointed; usually lower lobe slightly longer than upper lobe (opposite in one paratype); principal rays i, 7, 6, i (1)* or i, 6, 7, i (5).

Lateral line incomplete, pores extending just beyond vertical through posterior margin of pelvic-fin, at middle distance between dorsal fin to adipose fin; lateral line pores 8(4), 9(1), or 11*(1). Total gill rakers 5(2), 6(1), 7(2), or 9*(1). Axillary pore absent.

Color in alcohol. Ground color light brown; flanks covered by several darker stripes. Dorsal and lateral head dark brown, limited posterior at vertical trough pectoral fin; light stripe between posterior nostril and eye; thin, undulated light stripe between anterior and posterior nostrils. Large, quadrangular dark brown saddle on trunk, starting soon after vertical through base of pectoral fin, finishing at vertical through posterior dorsal-fin base. Dark brown blotch V-shaped on trunk, starting soon after dorsal fin, finishing at middle adipose fin, rarely surpassing body axis ventrally. Caudal peduncle dark brown blotch Y-shaped. Dorsal-fin base dark brown blotch confluent anteriorly to dark brown arched stripe along superior third dorsal-fin; oval-shaped hyaline blotch between dark brown areas; hyaline superior margin. Rounded light spot on dorsal-fin anterior base. Pectoral fin hyaline; several dark brown spots on middle region. Pelvic fin hyaline; several spots scattered irregularly. Dark brown blotch on anterior half of adipose fin confluent downward with V-shaped blotch of trunk. Dark brown blotch on anterior region of anal-fin base; dark brown stripe on posterior third. Caudal fin hyaline; dark brown spots scattered irregularly; dark brown stripe on posterior third. Ventral region light brown, covered by dark brown spots.

Distribution. Known from the upper rio Paraguay basin, in Mato Grosso and Mato Grosso do Sul states, Brazil ( Fig. 3 ), in one of the largest wetland regions in the world known as Pantanal. However, M. leniceae seems to be not common in the flooded area, occurring preferentially in small streams, as can be inferred from collection localities. Besides that, the species is possibly rare, as noticed by its absence in surveys of fish species for that region ( Willink et al., 2000; Teresa et al., 2010; Severo-Neto, 2015).

Etymology. The specific epithet is homage to Lenice Souza Shibatta, for her dedication to the study of biogeography and evolution of Neotropical fishes. A genitive noun.

Multivariate morphometrics analysis. The first Principal Component (PC) retained the largest amount of variance, 90.52% of original data, and all loadings of characters presented positive values. The second PC retained 3.36% and the third, 2.42%, with positive and negative characters loadings ( Table 2). Microglanis leniceae differs from M. carlae in the second PC, and from M. cottoides in the third PC ( Fig. 4 ). The variables that distinguish M. leniceae from M. carlae were the larger preanal length, adipose-fin base length, caudal peduncle depth (highest positive values), and the smaller orbital diameter (highest negative values); M. leniceae differs from M. cottoides by the larger body width (highest positive value), and shorter adipose-fin base length, anal-fin base length, posterior cleithral process length, and preanal length (highest negative values).

Conservation status. Few specimens of M. leniceae were obtained from collections, even if fish surveys in the region are made with frequency, leading to assume that the species is rare. However, the geographic distribution of M. leniceae at Pantanal region must be wide, as noticed from the dispersed localities of studied material in a broad geographic region with up to 115,000 km 2. In light of extent of occurrence superior to 20,000 km 2, without fragmentation, and lack of evidence indicating population decline or fluctuations, the current status of M. leniceae should be “Least Concern” or LC, according to IUCN Standards and Petitions Subcommittee (2016).

Figures

Fig. 1. Microglanis leniceae, holotype, ZUFMS 4148, 33.0 mm SL, rio Betione, Miranda, Mato Grosso do Sul State, Brazil.

Fig. 2. Dorsal view of right pectoral-fin spine of holotype (ZUFMS 4148, 33.0 mm SL) of Microglanis leniceae, from the upper rio Paraguay basin, Mato Grosso State, Brazil. Scale bar = 1 mm.

Fig. 3. Geographic distribution of Microglanis leniceae in states of Mato Grosso (MT) and Mato Grosso do Sul (MS) (yellow star = type locality). Brazilian states acronyms: GO = Goiás; SP = São Paulo.

Fig. 4. Scatter diagram of Sheared Principal Components analysis of combined samples of Microglanis leniceae (diamond, n = 6), M. carlae (squares,n= 9),andM. cottoides (triangle, n = 7).