Aspidoras marianae Leão, Britto & Wosiacki, 2015

Family:  Callichthyidae (Callichthyid armored catfishes), subfamily: Corydoradinae
Max. size:  2.85 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater,
Distribution:  South America: known only from its type locality, an unnamed stream tributary of the Rio Curuá, itself a tributary of the Rio Iriri in the Rio Xingu basin, Brazil (Ref. 114781).
Diagnosis:  Dorsal spines (total): -2; Dorsal soft rays (total): -8; Anal spines: -0; Anal soft rays: -7; Vertebrae: -23. Aspidoras marianae is distinguished from its congeners by having minute odontode-bearing platelets scattered over surface of snout region. It can be diagnosed from its congeners, except A. taurus, by having infraorbital 1 and 2 covered by thick skin and not visible externally (vs. externally visible), and from A. taurus by the possession of minute platelets between parieto-supraoccipital process and nuchal plate (vs. absence); from Aspidoras microgalaeus and A. belenos by the presence of 3 nasal pores (vs. 2); from A. velites by presenting ventral laminar expansion of the 1st infraorbital conspicuously expanded (vs. very reduced, almost absent in some specimens); by the number of dorsal-fin rays, II,7,i (vs. II,7-II,8); the reduced number of ventrolateral body plates, 22-23 (vs. 24-26); the greater depth of body, 28.0-31.0% SL (vs. 15.0-20.3%); the greater maximum cleithral width, 24.1-28.5% SL (vs. 12.5-17.1%); the greater head depth, 68.2-83.0% HL (vs. 53.2-64.6%); the greater least interorbital distance, 49.9-58.6% HL (vs. 30.3-38.3%); and the greater least internareal distance, 26.9-31.8% HL (vs. 11.1-17.9%); distinguish from A. microgalaeus by the greater head length, 32.5-38.6% SL (vs. 25.4-28.7%); the greater horizontal orbit diameter, 18.9-23.5% HL (vs. 10.1-17.0%); the reduced number of total free vertebrae, 23 (vs. 25); the 1st infraorbital notoriously expanded ventrally (vs. not expanded); anal fin with a diffuse blotch restricted to the base of the last 2 rays, and 1 blotch each over 3rd and 4th branched rays (vs. 2 series of dots on all rays); differs from A. belenos and A. brunneus, it by the overall coloration in a roughly marbled pattern (vs. characterized by stripes and/or solid, uniform coloration); also from A. belenos by conical serrations on the pectoral-fin spine (vs. bifid serrations) (Ref. 114781). Description: small species, largest specimen 28.5 mm SL; head slightly compressed, with convex dorsal profile; snout rounded in dorsal view; dorsal profile of body convex from snout dorsal-fin base; slightly concave from last dorsal-fin ray to caudal peduncle; ventral profile of body slightly convex from snout to pelvic girdle region; straight from this point to anal-fin origin; markedly concave from 1st anal-fin ray to caudal-fin base; body roughly elliptical in cross-section at pectoral girdle, gradually more compressed toward caudal fin; eye rounded, dorsolaterally on head; orbit delimited dorsally by frontal and sphenotic, anteriorly by lateral ethmoid, and ventral and posteriorly by infraorbitals; anterior and posterior nares very close, separated by thin skin flap; anterior naris tubular; small papillae on surface of snout; mouth small and subterminal; 1 pair of maxillary barbels and 2 pairs of mental barbels; maxillary barbel not reaching limit of gill opening ventrally; maxillary barbel slightly longer than outer mental barbel; inner mental barbel fleshy, nearly 1/4 of outer mental barbel length; minute rounded papillae over all barbels and upper and lower lips; minute odontode-bearing platelets scattered over surface of snout region; gill membranes united to isthmus; 4 branchiostegal rays covered by thick layer of skin; distal 2 rays united at their tips by branchiostegal cartilage; teeth on upper pharyngeal tooth plate 21(1), 24(1) or 25(1) in 2 rows, and on 5th ceratobranchial 22(1), 25(1) or 26(1) aligned in 1 row; minute vermiculate platelets homogeneously scattered over entire surface between isthmus and pelvic region; nasal, frontal, sphenotic, parieto-supraoccipital and compound pterotic visible externally, all covered by thin layer of skin and bearing minute scattered odontodes; 2 cranial fontanels; anterior small, ovoid, delimited by frontal bones, its posterior margin contacting anterior margin of parieto-supraoccipital; posterior rounded and smaller than anterior fontanel, restricted to middle of parieto-supraoccipital; nasal slender, slightly curved, inner margin contacting frontal; frontal quadrangular, anterior extension contacting nasal bone; posteriorly, frontal contacts sphenotic and parieto-supraoccipital; sphenotic quadrangular, contacting parieto-supraoccipital dorsally, compound pterotic posteriorly and infraorbital 2 ventrally; compound pterotic anterior portion contacting sphenotic anteriorly and parieto-supraoccipital dorsally; posterior portion contacting 1st dorsolateral body plate dorsally and 1st lateral line ossicle posteriorly; ventrally, compound pterotic contacting opercle and cleithrum; parieto-supraoccipital quadrangular, with elongated posterior process separated from nuchal plate by 1 dorsal body plate; minute platelets between these elements; 2 infraorbital bones, both covered by thick skin and not visible externally; 1st infraorbital notoriously expanded; opercle exposed, ovoid and roughly elongated; preopercle externally visible, slender and covered by thin layer of skin; interopercle quadrangular, covered by thin layer of skin; trunk lateral line composed of 1 perforated dorsolateral body plate (3rd) and 2 laterosensory canals, reduced to small ossicles; lateral line canal entering neurocranium through compound pterotic, splitting into 3 branches before entering sphenotic: pterotic, preoperculomandibular, and postero-lateral, each with single pore; postero-lateral branch open in compound pterotic itself, just above upper margin of opercle; sensory canal continuing through compound pterotic, entering sphenotic as temporal canal, which splits into 2 branches: 1 branch giving rise to infraorbital canal, other branch entering frontal through supraorbital canal; supraorbital canal with 2 branches: epiphyseal, opening near anterior fontanel; and anterior running through nasal bone; nasal canal with 1 opening anteriorly and 2 posteriorly; infraorbital canal running through entire 2nd infraorbital, extending to infraorbital 1 and opening into 2 pores; preoperculomandibular branch giving rise to preoperculomandibular canal, which runs through entire preopercle with 3 openings, corresponding to pores 3, 4 and 5, respectively; body plates with minute odontodes restricted to posterior margins; nuchal plate exposed; dorsolateral body plates 24 or 25; ventrolateral plates 22 or 23; dorsolateral body plates along dorsal-fin base 6 or 7; dorsolateral body plates from adipose-fin to caudal-fin base 8 or 9; preadipose platelets 4 or 5; precaudal vertebrae 8; caudal vertebrae 15; 6 pairs of ribs, 1st pair conspicuously larger than others; dorsal fin rectangular; its origin just posterior to third dorsolateral body plate; dorsal spine shorter than 1st 5 dorsal-fin rays and with smooth anterior and posterior margins; adipose origin just posterior to 16th or 17th dorsolateral body plate; preceded by small curved well-ossified spine; pectoral fin roughly triangular; origin just posterior to gill opening; ossified portion of pectoral spine shorter than all branched pectoralfin rays; anterior margin with small, scattered odontodes; posterior border of pectoral spine with 14-19 conical serrations, roughly perpendicularly oriented relative to main axis of spine; pelvic fin ovoid; origin just below 2nd ventrolateral body plate; anal fin roughly ellipsoid; origin just posterior to 13th or 14th ventrolateral body plate; caudal fin bilobed, lobes bluntly pointed and equal in size; principal caudal-fin rays i,6/6,i; procurrent caudal-fin rays 5or 6 and 5 or 6 on dorsal and ventral lobes, respectively; all fins with minute odontodes scattered on all rays (Ref. 114781). Color in alcohol: background coloration pale yellow; presence of 4 large brown blotches along midline of flank, 1st located between pectoral and pelvic girdles, 2nd between pelvic girdles and anal fin, 3rd above anal fin, and last on caudal peduncle and caudal-fin base; 1st, 2nd and 3rd blotches chevron shaped, 4th roughly triangular; tiny dark brown blotches on dorsal surface of head; more numerous and concentrated on parieto-supraoccipital region; elongated, oblique, dark brown blotch on antorbital portion; opercle with few brown saddles; roughly rounded, brown blotch on base of dorsal fin, from base of spine to interradial membrane after 3rd branched ray; small brown patches scattered along dorsal fin, larger until 3rd or 4th branched rays; dark spot on base of adipose-fin spine and few diffuse chromatophores on medial portion; pectoral spine with small, diffuse, light brown blotches on proximal and distal portions; with tiny chromatophores; small, light brown patches until 4th or 5th pectoral-fin rays; pelvic fin hyaline; anal fin with small, diffuse, light brown blotches restrict to base of last 2 rays, and 1 diffuse light brown blotch each over 3rd and 4th branched rays; 3 to 4 irregular, vertical series of small, brown blotches restrict to rays on caudal fin (Ref. 114781).
Biology:  Found in a slow-flowing stream with clear water and a sandy bottom with mud, leaf litter, submerged logs, and some aquatic macrophytes (Ref. 114781).
IUCN Red List Status: Not Evaluated (N.E.) Ref. (130435)
Threat to humans:  harmless

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