Dasyloricaria filamentosa ( Steindachner, 1878 )

Londoño-Burbano, Alejandro & Reis, Roberto E., 2016, Taxonomic revision and phylogenetic relationships of Dasyloricaria Isbrücker & Nijssen, 1979 (Siluriformes: Loricariidae), with description of a new species, Neotropical Ichthyology (Neotrop. Ichthyol.) 14 (1), No. e 150120, pp. 1-32 : 4-7

Dasyloricaria filamentosa ( Steindachner, 1878)

Figs. 3-4 , Tables 1-2

Loricaria filamentosa Steindachner, 1878: 45 , pl. 9, fig. 1 (type locality: río Magdalena, Colombia, Lectotype NMW 44874). Eigenmann, 1920b: 30 (lower río Magdalena); 1922: 90 (description). Schultz, 1944: 328 (description; tables of measurements and counts; distributed in lago Maracaibo basin). Miles, 1947: 112; fig. 61 (brief description; lower Cauca and Magdalena; identification keys).Dahl & Medem, 1964: 46 (brief description; río Sinú). Dahl, 1971: 92, fig. 101 (description). Galvis et al., 1997: 90 (repeat of Dahl, 1971 synonymy; brief description; Atrato, Sinú, Cauca, Magdalena, Cesar and Catatumbo basins; ventral and dorsal view photos).

Dasyloricaria filamentosa .—Isbrücker & Nijssen, in Isbrücker 1979: 87 (description of Dasyloricaria with D. filamentosa as type species; lectotype designation). Isbrücker, 1980: 111 (composition of Dasyloricaria ; species distribution; type series location); 1981: 10 (identification key for Loricariidae ). Rapp Py-Daniel, 1997: 142 (brief description; assignment to Spatuloricaria -Rhadinoloricaria clade). Ferraris, 2003: 333 (genus distribution; synonymy; type material location; maximum body size). Maldonado-Ocampo et al., 2005: 134, fig. 130 (description; distribution). Villa-Navarro et al., 2006: 13 (río Magdalena). Covain & Fisch-Muller, 2007: 4 (identification key for Loricariinae ; characters of Dasyloricaria ). Ferraris, 2007: 233 (synonymy; type-material depositories).

Loricaria filamentosa seminuda Eigenmann& Vance , inEigenmann, 1912: 13 (type locality: Girardot , Colombia, holotype FMNH 55116 , NEW SYNONYM). Eigenmann, 1920b: 30 (upper río Magdalena in Colombia). Ibarra & Stewart, 1987: 53 (holotype at FMNH; previous CM number).

Loricaria seminuda . — Eigenmann, 1922: 91, pl. XIV, figs. 1 and 2 (brief description of 182 mm SL specimen from Girardot, Colombia). Dahl, 1971: 92 (junior synonym of Loricaria filamentosa ; distribution; maximum and minimum body size; ontogeny; common names in Colombia).

Dasyloricaria seminuda .—Isbrücker & Nijssen, in Isbrücker, 1979: 87 (description of Dasyloricaria with D. filamentosa as type species). Isbrücker, 1980: 111 (composition of Dasyloricaria ; distribution; type series depositories); 1981: 10 (identification key for Loricariidae ). Ferraris, 2003: 333 (genus distribution; synonymy; types location, including “FMNH 55117” as holotype of D. seminuda [that lot holotype of Loricaria fimbriata ]; maximum body size; common names). Maldonado-Ocampo et al., 2005:135 (brief description; distribution; types at FMNH and USNM). Villa-Navarro et al., 2006: 13 (río Magdalena). Covain & Fisch-Muller, 2007: 4 (identification key for the Loricariinae ; characters of Dasyloricaria ). Ferraris, 2007: 234 (synonymy; location of type material, including “FMNH 55117” as holotype of D. seminuda [that lot holotype of Loricaria fimbriata ]).

Diagnosis. Dasyloricaria filamentosa is diagnosed by having six to eight dark transverse bars on dorsum (vs. none to four bars in D. latiura and eight in D. paucisquama ). It is further distinguished from D. paucisquama by having seven to 12 central abdominal plates in each row (vs. four to six); and the pelvic fin always surpassing the anal-fin origin (vs. pelvic fins never reaching the anal-fin origin). Dasyloricaria filamentosa is further distinguished from D. latiura by having the anterior abdominal plates smaller than central plates (vs. same size); the anal fin with welldefined spots without forming a distal band (vs. anal fin with black band on the distal portion of the rays); the black band covering the eyes never extending onto the snout (vs. the black band sometimes extending onto the snout); and the abdominal plate next to the pectoral-fin origin usually absent (vs. always present).

Description. Dorsal profile of head slightly convex to straight from snout to supraoccipital process. Dorsal profile of body slightly convex to straight from end of supraoccipital process to caudal-fin base. Plates at dorsal-fin base forming slight depression. Dorsal margin of orbit elevated; orbital notch well developed. Snout triangular in dorsal view. Odontodes poorly developed and not readily visible.

Upper lip with broad filaments that sometimes cover premaxillary teeth; short and thin filaments laterally on rictal barbel. Lower lip with filaments on posterior border similar to those on rictal barbel. Teeth slender and long in both premaxilla and dentary; number of teeth increases with ontogeny. Teeth bifid, main cusp longer and broader, almost twice as long as lateral.

Central abdominal plates always arranged in two rows in adults, without intervening spaces between them and lateral abdominal plates. Smaller plates in juveniles always arranged in two rows and with naked intervening spaces between them, lateral abdominal plates and posterior abdominal plates. Space between central and lateral abdominal plates frequently broader than single plate row of central abdominal plates. Anterior abdominal plates rounded, without regular arrangement and having naked space between anterior most plates and filaments of lower lip border.

Plates in mid-ventral and median lateral series with well-developed keels. One pair of predorsal plates between supraoccipital and nuchal plate with two well-developed keels.

Posterior margin of dorsal fin concave; its distal tip when adpressed reaching sixth to ninth plate posterior to dorsalfin base. Posterior pectoral-fin margin straight or slightly convex; spine long, reaching to or barely surpassing pelvicfin origin. Posterior pelvic-fin margin straight or slightly convex; third and fourth branched rays longest and barely reaching anal-fin origin. Distal anal-fin margin straight to rounded; second branched ray longest. Tip of anal-fin spine reaching seventh or eighth plate posterior to its base; three plates along anal-fin base. Posterior caudal-fin margin concave, upper ray extended into long filament usually as long as or longer than SL.

Color in alcohol. Ground color of head and trunk greyish brown dorsally; pale yellow or light brown ventrally. Upper lip filaments grey or pale yellow; upper and lower lips pale yellow. Six to eight transverse, dark, dorsal bars; first bar crossing eyes, second bar on predorsal paired plates ( Fig. 3 ). Small and irregular black spots present on dorsal-, pectoral- and pelvic-fin rays and membranes. Anal fin with scattered black spots not forming bands. Caudal-fin rays with black spots at base and complete black vertical band distally.

Sexual dimorphism. Poorly developed hyperthophied odontodes on the lateral portions of head, pectoral- and pelvic-fin spines and sometimes on the supraoccipital in males. Thickening of pectoral-fin spine was observed, associated with sexual maturity in some males. Females lack these sexually dimorphic features.

Distribution. Dasyloricaria filamentosa occurs in the lower and middle Magdalena basin, lower Cauca, and the río Sinú in Colombia, and the lago Maracaibo basin in Colombia and Venezuela ( Fig. 2 ).

Remarks. Steindachner (1878) described Loricaria filamentosa from specimens collected in the río Magdalena, Colombia, without a precise locality. Eigenmann (1912) indicated that the specimens used by Steindachner were collected in the lower portion of the río Magdalena, but this information was not found in the NMW field records (W. Helmut, pers. com.). According to the observations herein, Eigenmann was correct concerning the distribution of D. filamentosa in the lower and middle portions of the río Magdalena basin (see material examined; Fig. 2 ).

Dahl & Medem (1964) and Galvis et al. (1997) recorded this species in the río Sinú, Colombia, an occurrence corroborated herein. Galvis et al. (1997) and Maldonado- Ocampo et al. (2005, 2006) reported that D. filamentosa is widely distributed in northern South America, in the Catatumbo, Magdalena, Cauca, Sinú, San Jorge, and Atrato basins, what is not confirmed here, since D. filamentosa is only found in the Maracaibo, Magdalena and Sinú basins.

In their original description of Loricaria filamentosa seminuda, Eigenmann & Vance (in Eigenmann, 1912) indicated that the only difference between their subspecies and D. filamentosa was a naked space between the central and the lateral abdominal plates. This difference was observed in this study to reflect ontogenetic variation with the plate arrangement described for D. f. seminuda being the juvenile condition of the plates in adults of D. filamentosa . This was also noted by Steindachner (1878: 47), who commented “…the central rows are rudimentary in young specimens and are not in contact; in adult specimens it is not strange for them to be divided…” (our translation).

Dahl (1971), in a study of the fishes of northern Colombia, proposed D. filamentosa as a senior synonym of Loricaria fimbriata Eigenmann & Vance, 1912 , Dasyloricaria seminuda , D. latiura and D. tuyrensis . The author discussed about the few specimens used by Steindachner in the original description of D. filamentosa , and suggested that the five species belonged to an ontogenetic series of a single species, having collected himself the five species at the same locality. In this study we found that D. filamentosa is the senior synonym of D. seminuda , but we rejected the remaining synonyms proposed by Dahl, since D. latiura is a valid species with D. tuyrensis as its junior synonym and L. fimbriata was transferred to Spatuloricaria .

The description of Loricaria filamentosa seminuda (in Eigenmann, 1912) was based on five specimens collected at Soplaviento (CM 3804a-b and IUM 12694a-c) and a single specimen from Calamar (CM 3805); both localities in the lower Magdalena basin (Bolivar, Colombia). Those specimens were later mistakenly cataloged at FMNH as the type series of L. f. seminuda (FMNH 55113, 55114, 55116). The specimens in FMNH 55113 (CM 3804) and FMNH 55114 (CM 3805) were collected in the lower río Magdalena and identified as D. filamentosa . These were not among the specimens included in the original description of D. seminuda , and thus not types of the species. In addition, FMNH 55116 (CM 3807) is not a syntype, but the holotype of Loricaria filamentosa seminuda according to Eigenmann (1912: 13; 1922: 91), who indicated it as “type” of that species. The collection data of this specimen reads only “Girardot”, a city in Cundinamarca Department, Colombia, in the upper río Magdalena. The holotype of Loricaria filamentosa seminuda is the only record of this species in the upper Magdalena, and a confirmation of its exact locality is needed.

Steindachner (1878) reported the presence of hypertrophied lower lip on mature males of D. filamentosa , a feature suggesting that the species is a lip brooder. That characteristic was not, however, observed on the specimens in this study. It is uncertain whether this is a function of the collection period during the year, or if the samples are composed only of females and/or non-nuptial males. Ecological studies on the species and the genus in general are lacking.

Figures

Fig. 3. Dasyloricaria filamentosa. CP-UCO 350, 192.9 mm SL, Colombia, Caldas Department, Norcasia, río La Miel at La Cachaza, middle Magdalena basin, 5°39’N 74°46’W.

Fig. 4. Lectotype of Loricaria filamentosa. NMW 44874, 233.2 mm SL, Colombia, río Magdalena basin (exact locality unknown; photo provided by W. Helmut).

Fig. 2. Map of northwestern South America (Colombia, Panama and Venezuela) showing the distributions of species of Dasyloricaria. Black dots: Dasyloricaria filamentosa; black squares: D. paucisquama; black triangles: D. latiura; white circle: holotype of Loricaria filamentosa seminuda (=Dasyloricaria filamentosa); white square: holotype of D. paucisquama; white triangle: lectotype of Loricaria filamentosa latiura; and white star: holotype of Loricaria capetensis (= Dasyloricaria latiura) and holotype of L. tuyrensis (= Dasyloricaria latiura).