Rineloricaria maacki, Ingenito & Ghazzi & Duboc & Abilhoa, 2008
Ingenito, Leonardo F. S., Ghazzi, Miriam S., Duboc, Luiz F. & Abilhoa, Vinícius, 2008, Two new species of Rineloricaria (Siluriformes: Loricariidae) from the rio Iguaçu basin, southern Brazil, Neotropical Ichthyology 6 (3), pp. 355-355 : 355-
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Rineloricaria maacki , new species
Paratypes. MHNCI 11457 View Materials , 2 View Materials (1 male, 1 female), 113.0-128.0 mm SL, collected with the holotype . MHNCI 11455 View Materials , 1 View Materials (female), 102.8 mm SL, Brazil, Paraná, Lapa, areal Água Azul, rio Iguaçu , 50°11’34”W 25°47’34”S, 22 Feb 2001, L. F. Duboc, L. F. S. Ingenito & F. Wegbecher GoogleMaps . MHNCI 11682 View Materials , 1 View Materials (female), 79.7 mm SL, Brazil, Paraná, Lapa, areal Água Azul, rio Iguaçu , 50°11’34”W 25°47’34”S, 10 Nov 2000, L. F. Duboc & L. F. S. Ingenito. NUP 2540, 3 (1 male, 1 female, 1 c&s female), 110.8-133.5 mm SL, Brazil, Paraná, Cruz Machado / Bituruna , Foz do Areia rerservoir, rio Iguaçu , approx. 51°37’W 26°00’S, 26 Oct 1998, NUPELIA. NUP 3059, 1 (male), 136.2 mm SL, Brazil, Paraná, Cruz Machado / Bituruna , Foz do Areia reservoir, rio Iguaçu , approx. 51°37’W 26°00’S, 6 Oct 1999 GoogleMaps , COPEL.
Diagnosis. Rineloricaria maacki is easily distinguished from all Rineloricaria species except from R. latirostris , R. microlepidogaster , R. misionera , R. baliola , R. tropeira , and R. anhaguapitan by having a naked pectoral girdle and the abdomen covered by plates (vs. pectoral girdle and abdomen completely covered by plates). In addition, the complete covering of plates of the abdominal region of Rineloricaria maacki distinguish it from R. setepovos (that has the abdo- 360 Two new species of Rineloricaria from the rio Iguaçu basin men naked); from R. aequalicuspis , R. maquinensis , and R. malabarbai (that have the abdomen variably covered, sometimes naked); and from R. reisi (that has the abdomen almost naked with few irregular platelets). Rineloricaria maacki can be distinguished from R. latirostris by the presence of five dorsal transverse bands (vs. six bands) and by having the dorsal unbranched caudal-fin ray not prolonged (vs. dorsal unbranched caudal-fin ray produced as a long filament); from R. misionera , it is distinguished by having the pectoral girdle completely naked (vs. pectoral girdle with, a few small, well-
L. F. S. Ingenito, M. S. Ghazzi, L. F. Duboc & V. Abilhoa 361
defined lateral plates). It can be distinguished from both R. anhaguapitan and R. baliola by its snout having a naked area not reaching to anterior most pore of infraorbital ramus of sensory canal species (vs. snout with a naked area reaching to anterior most pore of infraorbital ramus of sensory canal) and by having all fins, except the dorsal fin, without a distal dark band (vs. wide dark band covering the distal onehalf of all fins in R. baliola and the same color pattern on dorsal, anal and caudal fins in R. anhaguapitan ); and from R. microlepidogaster , by having abdominal plates between lateral abdominal bones arranged in four (vs. five to six) series and larger than abdominal plates of this species. Furthermore, R. maacki can be distinguished from R. microlepidogaster by having the pectoral fin usually not reaching the pelvic-fin origin (vs. pectoral fin surpassing pelvic-fin origin).
Description. Morphometric data in Table 2. Head and body deeply depressed. Body depth greatest at dorsal-fin origin. Head triangular in dorsal view. Dorsal profile slightly convex from the tip of the snout to dorsal-fin origin, thereafter gradually depressed up to caudal-fin base. Ventral profile of body nearly straight from snout tip to anal-fin origin, then becoming more depressed towards caudal-fin base. Caudal peduncle depressed forming lateral keels with 11 (3*), 12 (4) or 13 (2) coalesced plates from 28 (1), 29 (4*) or 30 (4) total lateral plates in middle series. Five lateral series of plates, mid-dorsal series present. Scapular bridge completely naked. Abdomen completely covered by plates. Four series of abdominal plates irregularly distributed. Pre-anal plate present and anteriorly rounded by three polygonal plates. Lateral abdominal plates four (3*), five (3) or six (3). Dorsal-fin base with five plate rows.Anal-fin base with two (2) or three (7*) plate rows. Two 362 Two new species of Rineloricaria from the rio Iguaçu basin
(2) or three (7*) rows of plates between urogenital pore and anal fin. Plate counts on opposite sides of body usually different, except at dorsal- and anal-fin bases.
Top of head and parieto-supraocciptal smooth. Ridges of parieto-supraocciptal slightly divergent posteriorly. Plates of first three mid-dorsal series without evident ridges, almost smooth. Upper edge of orbit low. Postorbital notch with variable deep, short and narrow, not surpassing one third of the orbital diameter.
Head and body covered by very small odontodes, making fish somewhat smooth. Mature males with small hypertrophied odontodes distributes only on lateral margins of the head and weakly on dorsum of pectoral fin ( Fig. 5 View Fig ). Snout tip with wide naked area, not reaching last pore of infra-orbital ramus of sensory canal. Snout tip ventraly naked, without odontodes between it and upper lip. Lips well developed and covered by papillae; only one irregular papillae row at anterior most area of the upper lip. Two rows of inconspicuous papillae separating upper and lower lips. Maxillary barbel thin and shorter than orbital diameter. Notch present in lower lip. Teeth bicuspid with lateral cusp smallest than medial. Premaxilla with five (2*), six (1), seven (3) or eight (3) teeth.Dentary with five (2), six (1), seven (1) or eight (5*) teeth. Total number of vertebrae 32. Five ribs attached to vertebrae 7 to 11.
Pectoral-fins rays seven (i,6); fin margin sometimes reaching pelvic-fin origin when adpressed. Pelvic-fin rays six (i,5). Dorsal-fin rays eight (i,7); first ray shorter than head lenght; its origin located dorsal of pelvic-fins base. Anal-fin rays six (i,5). Caudal-fin rays 12 (i,10,i); its distal margin slightly concave; dorsal principal rays longer than ventral rays; in two
L. F. S. Ingenito, M. S. Ghazzi, L. F. Duboc & V. Abilhoa 363
specimens dorsal unbranched ray slightly elongated, extending distally less than one-third of orbital diameter and not prolonged as filament.
Color in alcohol. Ground color of dorsal surface light brown with darker small spots or vermiculated lines. Parietosupraocciptal dark brown. Five dark brown transverse bars across body; first on dorsal-fin origin, second on distal margin of dorsal-fin rays, third near vertical line surpassing through tip of anal-fin rays, fourth and fifth over caudal peduncle. Pores of laterosensory system without evident dark chromatophores. Ventral surface of the body pale or yellowish.
Fins yellowish with interradial skin hyaline and small darkbrown blotches on its rays. Blotches of distal margin of caudal fin very expanded and jointed over interradial skin, forming one bar occupying only its distal third. Caudal fin with darkish base.
Distribution and habitat. Rineloricaria maacki is known from middle and lower rio Iguaçu, a tributary of the rio Paraná basin ( Fig. 6 View Fig ). This species inhabits the main channel and 364 Two new species of Rineloricaria from the rio Iguaçu basin finding consistent diagnostic characters to describe them. Those two species can only be assigned at present to a generic description of Rineloricaria lima , which is taxonomically problematic (see below).
The specimens mentioned by Reis & Cardoso (2001) were not available for examination during the present study. However, information provided by Wolmar B. Wosiacki (MPEG) indicates that the lot MCP 17455 View Materials examined by those authors is composed by at least one of the two new species assigned as Rineloricaria sp. aff. lima by us. This species was also cited by Vitule & Abilhoa (2003) for rio Piraquara (a headwater river of the rio Iguaçu basin), and it was part of a series of specimens cited by Ingenito et al. (2004) for upper Iguaçu basin (MHNCI 9133 and MHNCI 9212). The fishes assigned here to Rineloricaria sp. aff. lima are widely distributed in the river basins rio Piraquara, rio Negro and rio da Várzea, and are sympatric to R. langei in the rio Iraí. Moreover, comparisons carried out by us with Rineloricaria specimens from coastal drainages indicate that Rineloricaria sp. aff. lima seems to be widely distributed along the coastal drainages of Paraná State, where it is found with a new species under description by us, which is characterized by having a short body and naked thoracic and abdominal regions.
Rineloricaria lima , the type species of the genus, was collected by Johann Natterer from “Brazilian rivers” during the 18 years that he lived in Brazil (1817-1835) (Riedl-Dorn, 2000; Vanzolini, 2004). The type specimen of R. lima has been lost and the original description, which was based on a dry specimen, is poor and characterizes most of species of the genus. With the loss of the type specimen of R. lima ( Isbrücker, 1979) , and the extensive nature of Natterer’s travels (including the Amazon basin, rio Paraguay, rio Paraná, rio Paraíba do Sul, and to the cities of Curitiba (rio Iguaçu) and Paranaguá (coastal Atlantic drainages of Paraná State)), it is not easy to associate any specimen to this name until the designation of a neotype, what is beyond the scope of this paper.
The absence of ventral plates observed in R. maacki is widely variable among loricarids, but among species of Rineloricaria sensu lato this character is restricted to species from the rio Paraná basin ( R. latirostris , R. maacki ), rio Uruguay ( R. misionera , R. setepovos , R. anhaguapitan , R. reisi , R. capitonia , and R. tropeira ) and coastal drainages from southeastern and southern Brazil ( R. aequalicuspis , R. maquinensis , R. malabarbai , R. baliola , R. microlepidogaster , and an undescribed species from Rio de Janeiro State). This character is not exclusive to Rineloricaria but can be an indicative of common ancestry between some species from geographical range cited above, as suggested by Ghazzi (2008), and proposed by Isbrücker et al. (2001), Ferraris (2007), and Rodriguez & Reis (2008). However, such a hypothesis requires a phylogenetic analysis of the members of Rineloricaria , what is also beyond the scope of the present study. The distribution of Rineloricaria species having a naked ventral area may also indicate close biogeographic relationship among Paraná and coastal Atlantic drainages through rio Iguaçu, that strengthens the hypotheses of Ingenito et al. (2004) and Torres et al. (2008). Such hypotheses also may explain the morphological similarities among R. langei and R. quadrensis .
The species herein described do not corroborate the statement proposed by Rodriguez & Reis (2008), who recognized two ecomorphological groups of Rineloricaria inhabiting sandy or rocky habitats. Both R. langei and R. maacki inhabit mostly sandy environments. However, the two new species have the naked area of the tip of snout not reaching the most anterior pore of the infraorbital ramus of sensory canal, which was reported to be a characteristic of the “rocky group” according to Rodriguez & Reis (2008). Such incongruence also occurs in some of the species assigned by those authors to the “sandy group” (e. g. R. kronei , R. misionera , R. quadrensis , R. steindachneri , and R. strigilata ). Moreover, the presence of the mid-dorsal series of lateral plates in R. maacki , a character of the “rocky group”, also contradicts those authors’ statement. The variation evidenced here may indicate that such characters are not informative to distinguish the “sandy” and “rocky” species groups, or that the morphological characters proposed by Rodriguez & Reis (2008) are not associated to specific habitats.
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