Herichthys steindachneri

Maza-Benignos, Mauricio De La & Lozano-Vilano, Ma. De Lourdes, 2013, Description of three new species of the genus Herichthys (Perciformes: Cichlidae) from eastern Mexico, with redescription of H. labridens, H. steindachneri, and H. pantostictus, Zootaxa 3734 (2), pp. 101-129 : 117-119

Herichthys steindachneri ( Jordan & Snyder 1900)

Figures 12, 13 , and 15; Tables 4 and 5

Holotype. SU 6164 (1: 61 mm SL, young fish) Rio Verde, Rio Rascón, San Luis Potosí, Mexico, D. S. Jordan & J. O. Snyder, January 24, 1899.

Material examined. Two specimens, 100.4–154.7 mm SL. San Luis Potosí: UANL 17437 (2: 100.4–154.7 mm SL), Tamasopo, San Luis Potosí, Mexico, Lat. 22.51666667, Long. −99.65, 393 masl, M. de la Maza- Benignos, March 0 8, 2006.

Diagnosis. Very elongate. Transition to predorsal contour pointed and acute. The robust-walled saccular stomach (14.26% of SL) rugged with longitudinal folds, and adhered at anterodorsal section of short (11.9% of SL), elastic, and smooth caecum. Gut-coiling pattern simple, S-shaped, shortened. Lower pharyngeal plate slender (slightly broader than long), well-spaced, and indented. Two rows of 6–7 conic, non-enlarged, lightly pigmented teeth flank midline, 2 central-most posterior teeth stout; 18 unevenly spaced, slender, conic, anteriorly recurved teeth along posterior margin decrease laterally in size. Distinguished from other species in the genus in having the lower jaw extending beyond the upper jaw (prognathous), and a single teeth row in upper and lower jaws.

Description. Description is based on sexually mature specimens> 100.4 mm SL. Body very elongate, predorsal contour pointed and acute, not concave before the eye, and forehead is inconspicuous; nuchal hump absent. Dorsal and ventral contour straight to moderately convex with a moderate slope; mouth terminal; lower jaw extending past upper jaw (prognathous) in some specimens. Dorsal fin XV–XVI, 9–10, set forward with respect to vertical of posterior border of opercle (intersects between 1st and 3rd rays), depressed fin short, rarely extending beyond anterior 3rd of caudal fin. Anal fin V, 9. Scales in longitudinal series 28–31. Anterior teeth regularly set, well-spaced, conic, unicuspid, rounded, strongly recurved, and pointed, with erect implantation, a pair of welldeveloped recurved fangs in upper jaw, and a less developed pair in lower jaw; 28 teeth in outer series of premaxilla; 5–6 frontal teeth regularly set, acutely pointed, caniniform, and moderately stout necks; lateral and posterior teeth small, non-caniniform, and irregularly set; single row of teeth in lower and upper jaws.

The lower pharyngeal plate is slender (slightly broader than long), well-spaced, and indented. Two rows of 6– 7 conic, non-enlarged, lightly pigmented teeth flank midline; 2 central-most posterior teeth stout; 18 unevenly spaced, slender, conic, anteriorly recurved teeth along the posterior margin decrease laterally in size.

Robust-walled saccular stomach (14.26% of SL) rugged and with longitudinal folds; stomach adhered at its anterodorsal section to a short elastic smooth caecum (11.9% of SL). Gut-coiling pattern simple, S-shaped, shortened. Peritoneum lightly pigmented.

Coloration in preservative. The entire body is light tan and whitish, particularly on the ventral half. The snout is darker relative to the predorsal area and around the orbit. Speckles present in life fade away and are not visible in alcohol. Sides have six faint, indistinct vertical blotches, including a conspicuous marking at the base of the caudal fin. Fins are light and opaque. Patterns on sides are variegated with scattered dark markings over the dorsal half and caudal peduncle.

Live colors. The body is olive yellow, very bright in some, and sometimes very pale, almost whitish, with numerous fine dark speckles on flanks and dorsum of head. Small red marking at axil of the pectoral fins. The following data are from Artigas-Azas (2006): “Iris is yellow. An irregular black bar runs from just posterior of eye orbit to end of caudal peduncle, where it forms a black blotch; scattered black markings visible between lateral line and base of dorsal fin, and on caudal peduncle.” “Fins are translucent; a yellow edge present on dorsal and anterior portion of anal fin; some bluish-green visible on anterior part of anal and pelvic fins.”

Breeding pigmentation. Breeding pigmentation is typical of the genus but almost imperceptible. Little detail was recovered with regard to breeding colors.

Geographical distribution. A very rare species, endemic to Rio Gallinas in Tamasopo and Rio Frio, tributary to the Santa María upriver from Rascón, including Rio Tamasopo, Rio Agua Buena, and Rio Ojo Frío. Absent from Rio Tamasopo above waterfall.

Habitat and associates. Habitat is characterized by hard, clear waters with pH 7.8–8.3 over a rock substrate. It shares its habitat with H. tamasopoensis , H. pame sp. nov., Xiphophorus . montezumae , and Gambusia panuco among other species of fish. H. steindachneri prefers pools of fast-flowing rivers with aquatic and riparian vegetation, usually underneath smaller cascades. H. steindachneri is a piscivorous species that feeds mostly on Astyanax mexicanus .

Vernacular names: Mojarra de Steindachner, mojarra del Tamasopo, Steindachner’s cichlid, Tamasopo cichlid.

Conservation status. Endangered according to NOM 0 59 SEMARNAT 2010 and vulnerable according to IUCN, 2009.

Remarks: H. steindachneri is a rare species. For years, it was mistaken for H. labridens . Jordan and Snyder’s (1900) and Meek’s (1904) descriptions of H. steindachneri mentioning the localities of Forlon, Valles, and Rascón are based on a composite of H. steindachneri and H. pame sp nov. specimens described herein. However, the drawing shown by Jordan and Snyder (fig. 20, page 142), Meek (fig. 67, page 211) and Taylor & Miller (1983) is of H. steindachneri from the type S.U. 6164. Regan’s account (1906–1908) establishes Mexico, Rio Panuco , and its tributaries as the species range of distribution. However, this account matches any species within the labridens assemblage. The observations of Álvarez del Villar (1970) generally coincide with our observations, whereas his narrative describes “jaws anteriorly of equal size,” which is only the case in some specimens, particularly juveniles as illustrated by Chloe Leslie Starks. Hulsey et al. (2003) recovered H. steindachneri of Rio Gallinas, San Luis Potosí, and Rio Tamasopo, San Luis Potosi as a sister taxa to H. pame sp. nov. of Rio Tamasopo. The natural history and behavior of H. steindachneri was studied in detail by Artigas-Azas (2006).

Figures

FIGURE 13. UANL 17437 Herichthys steindachneri (154.7 mm SL). Mauricio De la Maza-Benignos, Figure 14.