Author: Springer, 1966
Field Marks:
Scyliorhinids with short and rounded snouts, no nasoral grooves, anterior nasal flaps small and not reaching mouth, labial furrows present on both jaws, short to moderately long, not reaching upper symphysis, dorsal fins equally large at midbases, caudal fin short, without enlarged denticles on dorsal margin, supraorbital crests present on cranium, colour pattern of spots and saddles present.
Diagnostic Features:
Body not tadpole-shaped, moderately stout to very slender, and cylindrical or spindle-shaped, tapering moderately to considerably to caudal fin; body firm and thick skinned, with well-calcified dermal denticles; stomach not inflatable; tail rather long, length from vent to lower caudal origin about 0.9 to 1.4 times in snout-vent length. Head moderately depressed, narrowly rounded and not wedge-shaped in lateral view; head short, less than 1/5 of total length in adults; snout short, less than 3/4 of mouth width, thick, and flattened, bluntly pointed in lateral view; snout not expanded laterally, rounded-parabolic and slightly bell-shaped in dorsoventral view; ampullal pores not greatly enlarged on snout; nostrils enlarged, but with incurrent and excurrent apertures only slightly open to exterior; anterior nasal flaps formed as broad triangular or narrow attenuated lobes without barbels, well separated from each other and ending slightly anterior to mouth; internarial space about 0.8 to 1.2 times in nostril width; nasoral grooves absent; eyes dorsolateral on head, broad subocular ridges present below eyes; mouth angular or arched, moderately long, with lower symphysis somewhat behind upper so that upper teeth are well-exposed in ventral view; labial furrows present along both upper and lower jaws, these short to rather long and extending nearly to level of upper symphysis of mouth or ending well behind it; branchial region not greatly enlarged, distance from spiracles to fifth gill slits about 2/5 to 3/5 of head length; gill slits lateral on head. Two dorsal fins present, about equal-sized or with the sebond slightly larger than the first; origin of first dorsal varying from about over pelvic midbases to over or slightly behind their insertions; origin of second dorsal varying from over the anal midbase to about over the anal insertion; pectoral fins moderately large, their width slightly less to considerably greater than mouth width; inner margins of pelvic fins not fused over claspers in adult males; claspers moderately long, fairly thick, and distally pointed, extending about half of their lengths or slightly less behind the pelvic fin tips; anal fin small and not greatly elongated, slightly smaller to slightly larger than pelvic fins, subequal to slightly smaller than dorsal fins, base length subequal to about 1.3 times the second dorsal base; origin of anal far behind pelvic bases, and insertion separated from lower caudal origin by a broad space varying from 1.2 to over 2 times the anal base; caudal fin short and broad to moderately elongated, less than a fifth of total length in adults. No crests of denticles on the caudal margins; supraorbital crests present on cranium. Colour dark grey or brown to tan with a variegated colour pattern of dark and white spots, and dark to dusky saddles on the sides and dorsal surface.
Remarks:
Springer (1966), originally proposed this genus for his two new dwarf South American Atlantic species S. maculatus and S. tenuis, which supposedly differed from other scyliorhinids in their extremely attenuated forms. Subsequently, Springer (1979) discovered that one of these species, S. tenuis grew to a relatively large size, and that its attenuateness was a juvenile character. The slender body of adult S. maculatus may be a juvenile characteristic retained in a dwarf adult, that is, a result of pedomorphosis. Also, two additional South American species of South American scyliorhinids formerly placed in Halaelurus (H. bivius and H. chilensis) were found by Springer to belong to this genus. In S. bivius at least, newly hatched individuals are as attenuate as adult S. maculatus.
Schroederichthes is close to Aulohalaelurus and Atelomycterus and needs to be critically compared with them.