Aspidoras fuscoguttatus Nijssen & Isbrücker, 1976

Tencatt, Luiz Fernando Caserta, Britto, Marcelo R., Isbrücker, Isaäc Jan Hendrik & Pavanelli, Carla Simone, 2022, Taxonomy of the armored catfish genus Aspidoras (Siluriformes: Callichthyidae) revisited, with the description of a new species, Neotropical Ichthyology (e 220040) 20 (3), pp. 1-159 : 63-73

Aspidoras fuscoguttatus Nijssen & Isbrücker, 1976

( Fig. 34 )

Aspidoras fuscoguttatus Nijssen & Isbrücker, 1976:118 (original description; type locality: córrego Corguinho , Mato Grosso State [now Mato Grosso do Sul], Brazil). — Reis , 2003:292 (listed). — Araujo , Garutti , 2002:89 (reproductive biology study; partim). — Araujo, Garutti, 2003:363 (ecological study; partim). — Ferraris , 2007:109 (listed). — Wosiacki et al., 2014:311 (morphological comparison). — Teresa , Carvalho , 2008:109 (ecological study). — Leão et al., 2015:582 (morphological comparison). — Tencatt, Bichuette, 2017:8 (morphological comparison).

Diagnosis. Aspidoras fuscoguttatus can be distinguished from its congeners, with exception of A. albater , A. aldebaran , A. azaghal , A. belenos , A. depinnai , A. kiriri , A. maculosus , A. mephisto , A. poecilus , and A. raimundi , by having inner laminar expansion of infraorbital 1 ranging from moderately to well developed (vs. extremely well developed in A. gabrieli and A. lakoi ; poorly developed in A. psammatides and A. velites ); from A. albater , A. aldebaran , A. azaghal , and A. mephisto by presenting anterior laminar expansion of infraorbital 1 ranging from well developed, surpassing middle of nasal capsule, to extremely well developed, reaching anterior margin of nasal capsule (vs. ranging from strongly reduced, at same level as posterior margin of nasal capsule, to moderately developed, reaching middle of nasal capsule in A. albater ; ranging from poorly developed, slightly surpassing posterior margin of nasal capsule, to moderately developed, reaching middle of nasal capsule in A. aldebaran ; moderately developed, reaching middle of nasal capsule in A. azaghal ; ranging from strongly reduced, not reaching posterior margin of nasal capsule, to moderately developed, reaching middle of nasal capsule in A. mephisto ); from A. belenos and A. kiriri plus A. aldebaran by having parapophysis of the complex vertebra ranging from poorly to moderately developed (vs. well developed); from A. depinnai by having small spots on dorsal fin (vs. spots absent); from A. maculosus by the following combination of features: absence of relatively large, well-defined dark brown or black blotches on top of the head (vs. presence), inner laminar expansion of infraorbital 1 generally well developed (vs. moderately developed), and frontal bone generally relatively wide, with width equal to or slightly larger than half of entire length (vs. narrow, with width slightly smaller than half of entire length); from A. poecilus it differs by having the following combination of features: inner laminar expansion of infraorbital 1 generally well developed (vs. generally moderately developed), flanks with more dark brown or black markings, not considering the number of blotches in the series along flank midline (vs. fewer markings), frontal bone generally relatively wide, with width equal to or slightly larger than half of entire length (vs. narrow, with width slightly smaller than half of entire length), and generally less evident dark brown or black stripe from anteroventral portion of orbit to upper lip lateral area (vs. generally more evident); it can be distinguished from A. raimundi by having the following combination of features: inner laminar expansion of infraorbital 1 generally well developed (vs. moderately developed), dorsal fin with small spots (vs. generally lacking small spots), and markings on ventrolateral body plates generally more numerous and evident, not considering the number of blotches in the series along flank midline (vs. markings on ventrolateral body plates, when present, generally fewer and less evident, not considering the number of blotches in the series along flank midline). Aspidoras fuscoguttatus differs from A. rochai by having preadipose azygous plates generally with similar sizes; anteriormost plates smaller than remaining plates in some specimens (vs. preadipose azygous plates with variable sizes, alternating between smaller and larger plates).

Description. Morphometric data presented in Tab. 5. Head compressed with convex dorsal profile; triangular or somewhat trapezoid in dorsal view. Snout moderately developed and slightly pointed; or rounded. Head profile convex from tip of snout to anterior nares; ascending slightly convex from this point to dorsal-fin origin; region of parieto-supraoccipital process, frontals and/or mesethmoid slightly concave in some specimens. Profile slightly convex along dorsal-fin base. Postdorsal-fin body profile slightly concave to adipose-fin spine; slightly concave from this point to caudal-fin base. Ventral profile of body slightly convex from isthmus to pelvic-fin origin; region of gill opening slightly concave in some specimens; nearly straight or slightly concave from this point to anal-fin origin; concave until caudal-fin base. Body roughly elliptical in cross section at pectoral girdle, gradually becoming more compressed toward caudal fin.

Eye rounded, located dorso-laterally on head; orbit delimited dorsally by lateral ethmoid, frontal and sphenotic, ventrally by infraorbitals. Anterior and posterior nares close to each other, only separated by flap of skin. Anterior naris tubular. Posterior naris close to anterodorsal margin of orbit, separated from it by distance equal to, slightly larger or smaller than naris diameter. Mouth small, subterminal, width larger than bony orbit diameter. Maxillary barbel moderate to large in size, ranging from not reaching to surpassing anteroventral limit of gill opening. Outer mental barbel slightly larger than maxillary barbel. Inner mental barbel fleshy, with base close to its counterpart. Lower lip moderately developed, small semicircular or triangular fleshy flap; with two triangular fleshy flaps in some specimens. Small rounded papillae covering entire surface of all barbels, upper and lower lips, snout and isthmus.

Mesethmoid short; anterior tip poorly developed, slightly smaller than 50% of bone length (see Britto, 2003:123, ch. 1, state 1; fig. 1B); or relatively well developed, equal to 50% of bone length (see Britto, 2003:123, ch. 1, state 0; fig. 1A); posterior portion wide, entirely or almost entirely covered by thick layer of skin. Nasal slender, curved laterally, inner margin with moderately- to well-developed laminar expansion; outer margin with reduced or moderately-developed laminar expansion; mesial border contacting only frontal; or contacting frontal and mesethmoid.

Frontal elongated, generally relatively wide, with width equal to or slightly larger than half of entire length ( Fig. 3B ); narrow in some specimens, with width slightly smaller than half of entire length ( Fig. 3A ); anterior projection ranging from short, with size smaller than nasal length, to moderate, with size equal to nasal length; anterior margin partially or entirely covered by thick layer of skin. Frontal fontanel relatively small, ellipsoid or somewhat rhomboid; posterior tip extension not entering anterior margin of parieto-supraoccipital. Sphenotic somewhat trapezoid, contacting parieto-supraoccipital dorsally, pterotic-extrascapular posteriorly, second infraorbital ventrally and frontal anteriorly. Pterotic-extrascapular roughly pipe-shaped, with posteriormost portion contacting first lateral-line ossicle, and ventral margin contacting opercle and cleithrum; posterior expansion almost entirely covering lateral opening of swimbladder capsule, leaving slender pseudotympanic area on its dorsal margin covered only by thick layer of skin. Parieto-supraoccipital wide, posterior process strongly reduced to poorly developed, not contacting nuchal plate. Parieto-supraoccipital medial keel expanded ventrally; laminar, with posterior portion at same level as posterior process tip; expanded posteriorly in some specimens, slightly surpassing tip of posterior process. Parieto-supraoccipital fontanel small, roundish; located medially on parieto-supraoccipital.

Two laminar infraorbitals with minute odontodes; infraorbital 1 large, ventral laminar expansion generally ranging from well developed to extremely well developed; poorly- or moderately-developed expansion in some specimens; anterior portion with laminar expansion ranging from well developed, surpassing middle of nasal capsule, to extremely well developed, reaching anterior margin of nasal capsule ( Fig. 35 ); inner laminar expansion generally well developed ( Fig. 5B ); single specimen with moderately-developed expansion (NUP 11397, 30.0 mm SL) ( Fig. 5C ); small portions of external surface covered by thick layer of skin; infraorbital 2 small, slender; with posterior laminar expansion generally moderately developed; relatively well developed in some specimens; inner laminar expansion moderately developed; posteroventral margin directly contacting posterodorsal ridge of hyomandibula, dorsal tip contacting only sphenotic; external surface partially covered by thick layer of skin ( Fig. 35 ). Posterodorsal ridge of hyomandibula, close to its articulation with opercle, oblong, relatively slender; exposed or entirely covered by thick layer of skin; dorsal ridge of hyomandibula, between pterotic-extrascapular and opercle, generally exposed; entirely covered by thin or thick layer of skin in some specimens; exposed areas generally bearing small odontodes. Interopercle covered by thick layer of skin on its anterior portion; or entirely covered by thick layer of skin; somewhat triangular, anterior projection ranging from poorly to well developed. Preopercle relatively slender, elongated, minute odontodes sparse on external surface. Opercle compact in shape, width larger than half of its length; free margin convex; posterodorsal region variably with smoothly concave area; without serrations and covered by small odontodes; entire surface or some portions of bony distal margin irregular in some specimens.

Four branchiostegal rays decreasing in size posteriorly. Hypobranchial 2 somewhat triangular, tip ossified and directed towards anterior portion, posterior margin cartilaginous; ossified portion well developed, about twice size of cartilaginous portion; extremely well developed in some specimens, about triple size of cartilaginous portion. Five ceratobranchials with expansions increasing posteriorly; ceratobranchial 1 with small process on anterior margin of mesial portion; ceratobranchial 3 with continuous postero-lateral margin; ceratobranchial 5 toothed on postero-dorsal surface, 25 to 30(8) teeth aligned in one row. Four epibranchials with similar size; epibranchial 2 slightly larger than others, with small pointed process on laminar expansion of posterior margin; epibranchial 3 with triangular uncinate process on laminar expansion of posterior margin. Two wide pharyngobranchials (3 and 4), pharyngobranchial 3 with triangular laminar expansion on posterior margin; triangular laminar expansion with notches in some specimens. Upper tooth plate oval, with 28 to 44 (8) teeth generally aligned in two rows on postero-ventral surface; aligned in three rows in specimen MZUSP 62269.

Lateral-line canal entering neurocranium through pterotic-extrascapular, branching twice before entering sphenotic: pterotic branch with single pore; preoperculomandibular branch conspicuously reduced, with single pore opening close to postotic main canal; more developed, with pore opening closer to anteroventral border of pterotic-extrascapular in some specimens; postotic main canal widens just posterior to pterotic branch. Sensory canal continuing through pterotic-extrascapular, entering sphenotic as temporal canal, which splits into two branches: one branch giving rise to infraorbital canal, another branch entering frontal through supraorbital canal, both with single pore. Supraorbital canal branched, running through nasal bone. Epiphyseal branch of supraorbital canal relatively long, with pore opening close to frontal fontanel. Nasal canal with three openings, first on posterior edge, second on posterolateral portion, generally fused with the first pore, and third on anterior edge. Infraorbital canal running through entire second infraorbital, extending to infraorbital 1 and opening into two or three pores. Preoperculomandibular branch giving rise to preoperculo-mandibular canal, which runs through entire preopercle with three openings, leading to pores 3, 4, and 5, respectively; pore 3 generally opening at posterodorsal ridge of hyomandibula.

Dorsal fin somewhat triangular, located just posterior to third dorsolateral body plate. Dorsal-fin rays II,8*(21), posterior margin of dorsal-fin spine smooth. Nuchal plate poorly to moderately developed in length; posterior portion exposed, with minute odontodes; anterior tip covered by thick layer of skin ( Fig. 36 ); nuchal plate entirely covered by thick layer of skin in specimen MZUSP 62269 (CS, 26.0 mm SL); spinelet extremely short or short; partially exposed; spine generally moderately developed, adpressed distal tip surpassing middle portion of dorsal-fin base; or poorly developed, adpressed distal tip reaching middle portion of dorsal-fin base; anterior margin with small odontodes. Pectoral fin roughly triangular, its origin just posterior to gill opening. Pectoral-fin rays I,8*(29), I,9(2); posterior margin of pectoral spine with 14 to 27 moderately- to well-developed serrations along almost its entire length; small region just posterior to origin of spine lacking serrations; some serrations directed towards origin of spine, perpendicularly directed or directed towards tip of spine; presence of bifid serrations in some specimens; base of branched rays with small laminar expansions on its inner margin, generally more evident on first rays; laminar expansions variably with irregular margins ( Fig. 37 ). Anteroventral portion of cleithrum partially exposed; posterolateral portion of scapulocoracoid reduced, externally visible. Pelvic fin oblong, located just below third or fourth ventrolateral body plate, and at vertical through third dorsal-fin branched ray. Pelvic-fin rays i,5*(21). Adipose fin somewhat triangular, separated from posterior origin of dorsal-fin base by eight or nine dorsolateral body plates. Anal fin somewhat triangular, located just posterior to 13 th or 14 th ventrolateral body plates, and at vertical through region of preadipose platelets. Anal-fin rays, ii,5(1), ii,6*(20). Caudal-fin rays i,11,i(2), i,12,i*(19), generally five or six dorsal and/or ventral procurrent rays; caudal fin bilobed, dorsal lobe generally slightly larger than ventral lobe; or lobes with similar size.

Two or three laterosensory canals on trunk; first ossicle tubular, second ossicle laminar, third lateral-line canal, if present, encased in third dorsolateral body plate. Body plates with conspicuous line of relatively large odontodes confined to posterior margins; dorsolateral body plates 25(1), 26(2), 27*(15), 28(3); ventrolateral body plates 23(1), 24*(13), 25(7); dorsolateral body plates along dorsal-fin base 6(16), 7*(5); dorsolateral body plates between adipose-fin spine and caudal-fin base 6(1), 7(1), 8(14). 9*(4), 10(1); preadipose platelets 3*(1), 4(5), 5(10), 6(5); single specimen (MZUSP 27298, 34.3 mm SL) with seven preadipose platelets; small platelets covering base of caudal-fin rays; small platelets disposed dorsally and ventrally between junctions of lateral plates on posterior portion of caudal peduncle. Anterior margin of orbit, above junction of frontal and lateral ethmoid, and dorsal and lateral portions of snout with small platelets in some specimens. Region between nuchal plate and posterior process of parieto-supraoccipital generally with small- to medium-sized platelets ( Fig. 3 ); Ventral surface of trunk generally densely covered by small irregular platelets.

Vertebral count 23(1), 24(3), 25(5); ribs 6(4), 7(5), first pair conspicuously large; parapophysis of complex vertebra generally moderately developed ( Fig. 8C ); poorly developed in some specimens ( Fig. 8B ).

Coloration in alcohol. Ground color of body light or brownish yellow, with top of head dark brown. Posterodorsal portion of head, region below eye, opercle and cleithrum with scattered dark brown or black chromatophores. Snout covered by dark brown or black chromatophores on its dorsal surface; chromatophores densely disposed in some specimens; generally forming dark brown or black rounded, striated or irregular spots; with dark brown or black diffuse stripe from anteroventral portion of orbit to upper lip lateral area in some specimens; ventrolateral portion of snout with dark brown or black chromatophores. Upper lip and maxillary barbel with dark brown or black chromatophores; area of lateral portion of upper lip with conspicuous concentration of dark brown or black chromatophores in some specimens; outer mental barbel with dark brown or black chromatophores, generally more evident on its proximal portion, in some specimens. Dorsal series of three to four dark brown or black blotches, first on anterior portion of dorsal-fin base, second on posterior portion of dorsal-fin base, third on adipose-fin base, and fourth, if present, on caudal-fin base; blotches variably diffuse or absent. Dorsal portion of body with conspicuous concentration of dark brown or black chromatophores between counterparts of dorsolateral body plates in some specimens. Ventral surface of body on region posterior to urogenital opening with dark brown or black chromatophores in some specimens. First dorsolateral body plate with conspicuous concentration of dark brown or black chromatophores; posterior margin of some dorso- and ventrolateral plates, and lateral line pores with conspicuous concentration of dark brown or black chromatophores in some specimens. Midline of flank with longitudinal series of four to six mediumto large-sized conspicuous dark brown or black blotches; blotches rounded, oblong or irregular; variably fused to each other. Dorsal half of dorsolateral body plates with dark brown or black chromatophores; region of posterior portion of dorsal-fin base and adipose-fin base with more concentrated chromatophores, forming conspicuous blotches in some specimens. Ventral half of dorsolateral body plates and dorsal half of ventrolateral body plates with concentration of dark brown or black chromatophores, forming conspicuous blotches in some specimens; blotches generally more evident on anterior portion of body and on area of flank midline blotches. Mid-ventral portion of ventrolateral body plates on area of flank midline blotches with concentration of dark brown or black chromatophores; variably forming conspicuous blotches; blotches generally more evident posteriorly to pelvic-fin origin; ventral portion of ventrolateral body plates with concentration of dark brown or black chromatophores, generally more evident posterior to anal-fin anterior origin, in some specimens. Dorsal fin with dark brown or black spots; aligned spots, forming longitudinal or oblique bars in some specimens; conspicuous concentration of dark brown or black chromatophores on some areas of membranes, forming larger dark brown or black patches in some specimens; dorsal-fin base with conspicuous concentration of dark brown or black chromatophores, generally more concentrated on bases of first and last branched rays; spine covered by dark brown or black chromatophores. Pectoral fin with dark brown or black chromatophores on its dorsal surface, generally more evident on spine and first branched rays; generally forming dark brown or black spots; spots more evident on first branched rays; diffuse spots in some specimens; or entirely hyaline; region of body around dorsal portion of pectoral-fin origin generally with concentration of dark brown or black chromatophores in some specimens. Pelvic fin generally hyaline or with sparse dark brown or black chromatophores on its dorsal surface; variably forming up to two oblong dark brown or black patches; region of body around dorsal portion of pelvic-fin origin with concentration of dark brown or black chromatophores in some specimens. Adipose-fin membrane with dark brown or black chromatophores; conspicuous concentration of dark brown or black chromatophores in some areas of membrane, generally more evident close to spine, forming isolated patches in some specimens; adipose-fin spine generally with dark brown or black chromatophores. Anal fin with conspicuous concentrations of dark brown or black chromatophores in some areas, generally more evident on its middle portion and bases of last branched rays; with one or two dark brown or black blotches in some specimens. Middle portion of caudal-fin base, posteriorly to last flank midline blotch, generally with small- to medium-sized dark brown or black blotch; blotch diffuse or fused with last midlateral blotch in some specimens. Caudal fin with three to six transversal dark brown or black slender bars.

Coloration in life. Similar to that observed in preserved specimens but with ground color of body grayish yellow in some specimens. Body covered by whitish yellow and green iridescent coloration ( Fig. 38 ).

Geographical distribution. Aspidoras fuscoguttatus is known from the upper rio

Paraná basin in Goiás, Mato Grosso do Sul, Minas Gerais, and São Paulo states, Brazil

( Fig. 10 ).

Conservation status. Aspidoras fuscoguttatus is currently known from several records in the upper rio Paraná basin, within the territories of Goiás, Mato Grosso do Sul, Minas Gerais and São Paulo states, and no threat to the species as a whole is suspected in the present moment. According to the International Union for Conservation of Nature ( IUCN) categories and criteria (IUCN Standards and Petitions Subcommittee, 2019), Aspidoras fuscoguttatus can be classified as Least Concern (LC).

Remarks. Aspidoras fuscoguttatus has also made it into the aquarium hobby ( Fig. 38 ). Though it was not recorded specifically in the rio Araguaia basin in Goiás but rather in the rio Paraná basin in this state, A. fuscoguttatus seems to represent the species identified as Aspidoras sp. C 36. Despite their vague collecting data, the specimens used to assign the codes C118 and C119, said to be from “ Brazil ”, strikingly resemble A. fuscoguttatus . Although C36, C118 and C119 may represent A. fuscoguttatus , no material of any of them could be examined herein.

Material examined. In addition to the material examined by Nijssen, Isbrücker (1976:118) the following material was analysed. All from Brazil, upper rio Paraná basin. DZSJRP 1359 , 20 of 29, 23.4–30.8 mm SL, São Paulo, córrego do Cedro. DZSJRP 4414 , 15 of 23, 14.7–30.2 mm SL, São Paulo, stream tributary to the córrego do Cedro. DZSJRP 4422 , 48 , 11.7–33.4 mm SL, São Paulo, stream tributary to the córrego do Cedro. DZSJRP 4877 , 17 , 20.0– 36.6 mm SL, São Paulo, córrego da Helena. 20.9–34.7 mm SL, São Paulo, córrego Feio. DZSJRP 4909 , 30 of 52, 18.1–31.3 mm SL, São Paulo, stream tributary to the córrego Veadão. DZSJRP 4957 , 10 of 17, 22.8–35.1 mm SL, São Paulo, córrego do Cajueiro. DZSJRP 5978 , 10 of 23, 15.7–23.9 mm SL, São Paulo, unnamed stream tributary to the ribeirão da Prata. DZSJRP 5897 , 7 , 16.5–28.7 mm SL, São Paulo, unnamed stream tributary to the rio São José dos Dourados. DZSJRP 5984 , 17 , 16.9–27.2 mm SL, São Paulo, unnamed stream tributary to the rio São José dos Dourados. DZSJRP 6056 , 20 of 35, 17.6–26.4 mm SL, São Paulo, stream tributary to the ribeirão Buritis. DZSJRP 6156 , 4 , 17.5–23.2 mm SL, São Paulo, stream tributary to the ribeirão Três Barras. DZSJRP 6187 , 29 of 44, 16.6–29.4 mm SL, 1 CS of 44, 29.9 mm SL, São Paulo, unnamed stream tributary to the rio São José dos Dourados. DZSJRP 7270 , 4 , 16.2–29.4 mm SL, São Paulo, unnamed stream tributary to the ribeirão Barreiro. DZSJRP 7277 , 15 of 25, 17.9–30.7 mm SL, São Paulo, unnamed stream tributary to the córrego Três Lagos. DZSJRP 9622 , 7 , 20.5–29.1 mm SL, São Paulo, córrego Açoita Cavalo. DZSJRP 9702 , 20 of 32, 15.9–32.6 mm SL, São Paulo, córrego Invernada. DZSJRP 9746 , 10 of 19, 18.1–39.1 mm SL, São Paulo, córrego do Gregório. DZSJRP 9822 , 23 , 14.6 –28.0 mm SL, São Paulo, córrego do Cerne. DZSJRP 9852 , 11 , 16.9 –25.0 mm SL, São Paulo, unnamed stream tributary to the ribeirão Onça. DZSJRP 9882 , 9 , 16.4–30.4 mm SL, São Paulo, unnamed tributary to the rio Turvo. DZSJRP 9898 , 6 of 7, 23.4–29.9 mm SL, 1 CS of 7, 30.8 mm SL, São Paulo, córrego do Barro Preto. DZSJRP 10944 , 9 , 19.7–26.9 mm SL, São Paulo, stream tributary to the rio Tietê. DZSJRP 11090 , 29 of 46, 11.7–27.6 mm SL, 1 CS of 46, 27.2 mm SL, São Paulo, córrego Sucuri. DZSJRP 14125 , 2 , 22.4–23.6 mm SL, São Paulo, tributary to the ribeirão Borboleta. DZSJRP 14959 , 10 of 11, 25.3–33.8 mm SL, 1 CS of 11, 34.2 mm SL, São Paulo, stream tributary to the rio Tietê. DZSJRP 18665 , 4 , 19.9 –22.0 mm SL, São Paulo, Volta Grande Reservoir. LBP 19447 , 1 of 4, 28.2 mm SL, São Paulo, unnamed stream tributary to the rio Grande. LIRP 8208 , 1 , 26.4 mm SL, São Paulo, córrego dos Buritis. LIRP 8214 , 11 , 14.9–25.1 mm SL, São Paulo, córrego Olhos d’água. LISDEBE 2560, 7, 13.5–29.5 mm SL, São Paulo, stream tributary to the córrego da Onça. LISDEBE 2901, 1, 18.1 mm SL, São Paulo, Virgolino Power Plant. LISDEBE 2917, 8, 18.4–24.2 mm SL, São Paulo, Virgolino Power Plant. LISDEBE 5489, 1, 15.5 mm SL, Mato Grosso do Sul, Jupiá Reservoir. LISDEBE 5561, 19 of 20, 19.6–28.9 mm SL, 1 CS, 30.4 mm SL, São Paulo, córrego do Taquaral. LISDEBE 5569, 1, 26.0 mm SL, São Paulo, ribeirão Tabarana. MNRJ 27298 , 3 , 25.6–34.3 mm SL, São Paulo, uncertain locality. MNRJ 29812 , 1 , 18.9 mm SL, São Paulo, córrego da Inácia. MNRJ 46493 , 10 , 20.5–31.9 mm SL, Minas Gerais, córrego Capão Rico. MNRJ 48933 , 4 , 20.2–22.4 mm SL, Minas Gerais, swampy area tributary to the rio Paranaíba. MZUSP 23138 , 7 , 22.4 –29.0 mm SL, São Paulo, córrego do Pernilongo. MZUSP 24516 , 1 , 30.5 mm SL, São Paulo, São José do Rio Preto. MZUSP 35833 , 30 of 34, 13.6–30.2 mm SL, São Paulo, córrego São José. MZUSP 47763 , 4 , 20.7 –24.0 mm SL, Goiás, ribeirão João Leite and tributaries. MZUSP 62269 , 46 of 47, 16.7–33.2 mm SL, 1 CS, 25.5 mm SL, Minas Gerais, ribeirão Boa Vista. MZUSP 73237 , 1 , 23.1 mm SL, Minas Gerais, stream tributary to the rio Piedade. MZUSP 85795 , 15 , 21.4–29.7 mm SL, São Paulo, stream tributary to the rio Pardo. MZUSP 88357 , 1 , 25.3 mm SL, Mato Grosso do Sul, stream tributary to the rio Paraná, crossing the road Três Lagoas-Selviria. MZUSP 92041 , 2 , 28.2–40.4 mm SL, São Paulo, córrego Tamburi. MZUSP 101002 , 1 , 23.4 mm SL, São Paulo, stream tributary to the rio Preto. NUP 9744 , 7 , 25.5–30.9 mm SL, Minas Gerais, córrego Candinho. NUP 11397 , 2 CS, 28.9‒30.0 mm SL, Goiás, rio dos Bois. NUP 12677 , 25 , 20.1– 38.3 mm SL, 2 CS, 36.1–36.8 mm SL, Goiás, rio Corumbá. NUP 19124 , 5 , 25.1‒27.9 mm SL, Minas Gerais, córrego do Jaó. NUP 19127 , 5 , 15.3 –25.0 mm SL, Minas Gerais, córrego Frutal. NUP 19133 , 1 , 30.9 mm SL, Minas Gerais, córrego Frutal. NUP 19137 , 2 , 23.2–24.1 mm SL, Minas Gerais, córrego do Marianhinho. NUP 19138 , 1 , 35.2 mm SL, Minais Gerais, córrego Frutal. ZUFMS-PIS 2358 , 1 , 20.5 mm SL, Mato Grosso do Sul, córrego do Morgado .

Figures

FIGURE 3 | Dorsal view of the head of CS specimens showing the three patterns of paired frontal bones (outlined in black) in Aspidoras: (A) narrow, with width of each frontal slightly smaller than half of its entire length (Aspidoras maculosus, UFBA 3291, 30.7 mm SL), (B) relatively wide, with width equal to or slightly larger than half of entire length (Aspidoras albater, MZUSP 40793, 29.4 mm SL), and (C) extremely narrow, with width clearly smaller than half of entire length (Aspidoras psammatides, UNT 9604, 27.3 mm SL). Scale bars = 1 mm.

FIGURE 5 | Dorsal view of the infraorbital series of CS specimens showing the four patterns of size and shape of the inner laminar expansion of infraorbital 1 (white arrows) in Aspidoras: (A) extremely well developed (Aspidoras albater, MNRJ 13080, 30.9 mm SL), (B) well developed (Aspidoras fuscoguttatus, NUP 12677, 36.1 mm SL), (C) moderately developed (Aspidoras poecilus, UNT 6249, 30.9 mm SL), and (D) poorly developed (Aspidoras psammatides, UNT 9604, 27.3 mm SL). Abbreviations: io1: infraorbital 1, io2: infraorbital 2. Scale bars = 1 mm.

FIGURE 8 | Ventral view of the complex vertebra in CS specimens of (A) Aspidoras belenos, paratype, UFRJ 4419 (ex-UFRJ 3861), 22.1 mm SL, with well-developed parapophysis, (B) Aspidoras albater, MNRJ 12571, 35.3 mm SL, with poorly-developed parapophysis, and (C) Aspidoras albater, MNRJ 12581 (disarticulated, indeterminate size), with moderately-developed parapophysis. Abbreviations: ccv: centrum of the complex vertebra, pcv: parapophysis of the complex vertebra. Scale bars = 1 mm.

FIGURE 10 | Map showing the geographical distribution of Aspidoras albater (type locality: red circle; non-type localities: black circles), A. aldebaran (type locality: red star; non-type localities: white stars), A. azaghal (purple triangle), A. belenos (type locality: purple diamond), A. brunneus (possible region of type locality: grey diamond), A. carvalhoi (type locality: purple circle), A. depinnai (type locality: red square; nontype localities: black squares), A. fuscoguttatus (type locality: red triangle; non-type localities: white triangles), A. gabrieli (type locality: red pentagon; non-type locality: white pentagon), A. kiriri (black cross), A. lakoi (type locality: red diamond; non-type locality: black diamond), A. maculosus (red cross), and A. mephisto (type locality: white cross). Each symbol may represent more than one locality.

FIGURE 34 | Aspidoras fuscoguttatus, holotype, MZUSP 8573, 29.5 mm SL, córrego Corguinho, Três Lagoas Road, Mato Grosso do Sul State, Brazil. Dorsal (top), lateral (middle) and ventral (bottom) views. Photo in lateral view by Eduardo Baena.

FIGURE 35 | Lateral view of the head of CS specimen of Aspidoras fuscoguttatus, DZSJRP 9898, 30.8 mm SL, showing its general infraorbitals pattern. Abbreviations: io1: infraorbital 1, io2: infraorbital 2, sph: sphenotic, pes: pterotic- extrascapular. Scale bar = 1 mm.

FIGURE 36 | Aspidoras fuscoguttatus, DZSJRP 9898, CS, 30.8 mm SL, showing predorsal region of trunk in dorsal view. Abbreviations: np: nuchal plate, pso: parieto-supraoccipital. Scale bar = 1 mm.

FIGURE 37 | Aspidoras fuscoguttatus, LISDEBE 5561, CS, 30.4 mm SL, showing dorsal view of the pectoral fin. Arrows indicate the small laminar expansions at the base of branched rays. Scale bar = 1 mm.

FIGURE 38 | Uncatalogued aquarium specimens of Aspidoras fuscoguttatus from the córrego Bacalhau, upper rio Paraná basin, Goiás State, photographed alive. (A) female and (B) a pair, with female on the left and male on the right. Photos by Hans Evers.