Stenocercus aculeatus O'Shaughnessy , 1879

Venegas, Pablo J., Garcia-Ayachi, Luis A., Chavez-Arribasplata, Juan C., Chavez, German, Wong, Ivan & Garcia-Bravo, Antonio, 2020, Four new species of Stenocercus Dumeril & Bibron, 1837 (Squamata, Iguania) from the Department of Amazonas in northeastern Peru, Evolutionary Systematics 4 (2), pp. 79-108 : 79

Stenocercus aculeatus O'Shaughnessy, 1879 Figs 4C, D , 8B , 9B, D, F , 15

Note.

An elusive species represented by five specimens in museum collections ( Cadle 2001; Torres-Carvajal 2007a). Currently it is known from five localities at elevations of 723 and 1311 m between Zamora, in the Andes of southern Ecuador, and its southernmost record in Pampa Seca at Department of La Libertad in northern Peru ( Cadle 2001; Torres-Carvajal and Carvajal-Campos 2009). No data about its natural history and coloration in life exist and probably due to its disjunct distribution more than one species is represented under its specific epithet.

Collecting specimens in the Andes of northern Peru for almost two decades, we acquired only two specimens of S. aculeatus in two locations of Abra Patricia at elevations of 1700 and 1990 m, just at the limits of the departments of Amazonas and San Martín (Fig. 5 ). Extending its altitudinal range by 679 m above its previously known record, Pampa Seca in the Mishollo Valley, at an elevation of 1311 m ( Cadle 2001), one of the specimens ( CORBIDI 1712) is also the first report for the Department Amazonas. Both specimens have scale counts similar to the description of Torres-Carvajal (2007a).

Abra Patricia is the pass between the Río Chiriaco and Río Mayo basins located in the Peruvian Yungas, according to Olson et al. (2001). It is a steep area mostly covered by humid montane forest with an abundance of orchids, bromeliads, lichens and Chusquea spp. Kunth, 1882. The forest at the base and on the slopes is 3 to 5 m of high, decreasing in height toward the tops. Some slopes are rocky and very steep with only shrubby vegetation or long grasses. The weather is rainy most of the year and hours with sun are usually limited.

One specimen ( CORBIDI 11483) was collected by ornithologists of the Louisiana State University during an ornithological expedition to Abra Patricia in August 2002. The specimen is an adult male of 95 mm SVL preserved in ethanol with an overall dark gray coloration. Only a black patch extensively covering the gular region is dark enough to observe. Although no collecting data is available for this specimen the area where it was collected is a steep slope covered by montane forest near a cleared area for cattle ranching.

The second individual (Fig. 15 ) is another adult male ( CORBIDI 1712) of 80 mm SVL and was collected by P.J. Venegas in October 2008. This specimen was encountered during the morning at 1000 hours on the top of long grass at a height of 50 cm in a flat area with scattered scrubs and grasses close to the road. The specimen was lethargic due to lack of sun, being easy to capture. The same day at 1200 hours three more individuals were observed: one male basking at the base of long grasses on a steep rocky wall close to the road and a couple were observed on a trail along a summit covered by scrub and scattered boulders to 200 m from the road. These individuals ran to hide at the base of dense scrub when they detected PJV getting closer, and were impossible to capture.

Coloration in life of adult males ( CORBIDI 1712): dorsal surface (Fig. 4C ) is dusty brown with a sepia hue on dorsum, bearing dark brown transverse bands with narrow cream interspaces; vertebral crest is greenish yellow with the tip of some spines brown; limbs and tail with faint cream transverse stripes; coloration of flanks similar to dorsum but with the ventrolateral region bluish; side of neck and arm insertion cream; dorsal surface of head dark brown with the occipital region darker; sides of head dark brown with the loreal and subocular region white, interrupted by a diagonal dark brown subocular stripe, snout dark brown, tympanic region and ventrolateral region of neck black. Ventrally (Fig. 4D ), the anterior half of the gular region dirty cream and the rest of the gular region and ventral surface of neck black; chest, forearms and belly brownish cream with a thin dark brown stripe from the chest to the end of belly, sides of belly bluish gray; pelvic region and ventral surface of hindlimbs tan, a cream blotch on the cloacal region; proximal half of tail creamy tan with faint brown transverse bands the rest of tail brown.

Figures

Figure 4. Dorsolateral and ventral views of adult males of three species of Stenocercus: (A, B) S. huancabambae, (C, D) S. aculeatus, (E, F) S. prionotus from northern-central Peru, and (G, H) S. prionotus from southern Peru. Photographs by: (A - D) Pablo J. Venegas, (E) Andy Barboza, (F) Diego Vasquez, and (G, H) German Chavez.

Figure 5. Distribution map of S. catherineae sp. nov. (red triangles), S. dracopennatus sp. nov. (yellow star), and S. philmayi sp. nov. (blue squares), and the similar species: S. aculeatus (fuchsia diamonds), S. angulifer (blue diamonds), S. huancabambae (orange diamonds), S. prionotus (turquoise diamonds), and S. scapularis (red diamonds). Symbols with a dot in the middle correspond to type localities. White circles with a dot are important cities for reference.

Figure 8. Lateral view of head and posthumeral mite pockets of adult male Stenocercus for comparison: (A) S. dracopennatus sp. nov. (CORBIDI 18868), (B) S. aculeatus (CORBIDI 11483), (C) S. dracopennatus sp. nov. (CORBIDI 18875), and (D) S. aculeatus (CORBIDI 1712). Photographs by Luis A. Garcia-Ayachi. Scale bars: 5 mm.

Figure 9. Lateral and dorsal views of adult males of Stenocercus for comparison: (A, C, E) S. dracopennatus (CORBIDI 18875) and (B, D, F) S. aculeatus (CORBIDI 1712). Photographs by Luis A. Garcia-Ayachi. Scale bars: 10 mm.

Figure 15. Stenocercus aculeatus preserved specimen, adult male, SVL 80 mm (CORBIDI 1712): dorsal (A), lateral (B), and ventral (C) views of the head; dorsal (D) and ventral (E) views of the entire specimen. Photographs by Luis A. Garcia-Ayachi. Scale bars: 10 mm.