Pterocryptis anomala

biology_ecology

Habitat and ecology. Pterocryptis anomala is found in habitats from sea level to at least 760 m a. s. l. (M. Lau, pers. comm. to BPLC). It prefers boulder-strewn, fast-flowing streams with step-pool formation. The fish are largely nocturnal and hides amongst rocks and submerged plant roots during the day, but can be seen during overcast days or in shaded stream pools. When active, P. anomala hovers near the streambed searching for small invertebrates. Stream water in Hong Kong is typically soft, slightly acidic, with a conductivity of less than 50 µs / cm, and dissolved oxygen level between 0.4 - 1.0 mg / L (BPLC, unpubl. data). Fish species typically found syntopically with P. anomala include Parazacco spilurus spilurus, Psuedograstromyzon myersi, Liniparhomaloptera disparis disparis, Schistura fasciolata, Oreonectes platycephalus, and Rhinogobius duospilus.

Revalidation and redescription of Pterocryptis anomala (Herre, 1933), a catfish (Teleostei: Siluridae) from southern China.

description

Description. Biometric data is given in Table 2. Body laterally compressed. Head somewhat depressed. Dorsal profile straight, descending gently from dorsal-fin origin to snout tip. Anterior profile of snout rounded. Anterior pair of nostrils tubular and anteromedial to maxillary barbel base. Posterior pair of nostrils bordered by fleshy dorsal and ventral membranes and situated posteromedial to maxillary barbel base. Eyes small, subcutaneous; located in anterior half of head; visible dorsally, but not ventrally. Mouth subterminal; gape horizontal or very slightly oblique. Well-developed rictal fold present, consisting of large and fleshy upper lobe joined at corner of mouth with lower lobe; lower lobe subtended by short submandibular groove. Teeth villiform. Dentary teeth in slightly curved, elongate bands narrowing posteriorly, reaching from symphysis almost to mouth corners; premaxillary teeth in broader, slightly curved rectangular bands; vomerine teeth in a single crescent-shaped band.

Revalidation and redescription of Pterocryptis anomala (Herre, 1933), a catfish (Teleostei: Siluridae) from southern China.

description

Distal margin of dorsal fin pointed, with i, 2, i (50) or i, 3, i (11) rays; segments of first ray not co-ossified to form spine. Distal margin of pectoral fin broadly convex, with 9 (1), 10 (5), 11 (46) or 12 (9) rays. Segments of the proximal two-thirds of first pectoral-fin element co-ossified, forming spine. Pectoral spine and articulated segments sexually dimorphic in mature individuals. Spine in males with broad and somewhat flattened dorsoventrally, with 5 - 9 serrations on posterior edge, increasing in size distally; proximal articulated segments with 0 - 6 serrations on posterior edge. Spine in females or juveniles slender, with 0 - 7 small serrations on posterior edge, and 0 - 3 serrations on posterior edges of proximal articulated segments. Distal margin of pelvic fin convex, with i, 6, i (44) or i, 7, i (17) rays. Distal margin of anal fin straight, with 59 (7), 60 (4), 61 (10), 62 (6), 63 (9) 64 (4), 65 (3), 66 (8), 67 (5), 68 (3) or 69 (2) rays; joined to caudal fin for length of last anal-fin ray. Integument over anal fin thickened proximally for slightly more than half of ray lengths; fin-ray erector muscles extending along anterior edges of anal-fin rays, ventralmo

Revalidation and redescription of Pterocryptis anomala (Herre, 1933), a catfish (Teleostei: Siluridae) from southern China.

description

Maxillary barbels slightly flattened, reaching to anterior third of anal fin. One pair of mandibular barbels present; located slightly anterolateral to gular fold; barbels flattened for most of length, reaching to middle of pectoral-fin base. Gill membranes separate and overlapping, free from isthmus. Branchiostegal rays 9 (3), 10 (35), 11 (18), 12 (4) or 14 (1). Gill rakers short, anteriormost rakers on lower first arch small and widely spaced; 2 + 4 (6), 1 + 6 (3), 2 + 5 (9) 2 + 6 (1), 3 + 5 (8), 4 + 5 (1) or 3 + 7 (1).

Revalidation and redescription of Pterocryptis anomala (Herre, 1933), a catfish (Teleostei: Siluridae) from southern China.