Amphisbaena Linnaeus, 1758

Costa, Henrique C., Welton, Luke J. & Hallermann, Jakob, 2018, An updated diagnosis of the rare Amphisbaenaslateri Boulenger, 1907, based on additional specimens (Squamata, Amphisbaenia, Amphisbaenidae), Evolutionary Systematics 2 (2), pp. 125-135 : 125-127

Amphisbaena Linnaeus, 1758

Amphisbaena slateri Boulenger, 1907: 487.

Heterochresonymy.

Amphisbaena darwinii : ( Werner 1910) - erroneous identification of ZMH R05908.

Type material.

Holotype, BM 1946.8.31.82 (former 1907.5.2-RR), undetermined sex, collected sometime prior to 2 May 1907 by Thomas Slater and presented by him to the British Museum through Prof. G. S. Boulger ( Boulenger 1907) (Figure 1).

Type-locality.

San Gaban river valley, Provincia de Carabaya, Departamento de Puno, Peru, between 2000-3000 feet (~600-900 m) above sea level. Originally cited as "Peru, obtained in the Rio San Gaban Valley, Prov. Carabaya, altitude 2000-3000 feet" ( Boulenger 1907).

Definition.

Amphisbaena slateri is defined by the following combination of characters: (1) rounded head, not compressed or depressed; (2) length of frontal suture> <prefrontal> nasal sutures; (3) four precloacal pores with out a median hiatus; (4) lateral sulcus present, dorsal and ventral sulci absent; (5) 176-213 body annuli; (6) three or four lateral annuli; (7) 20-24 caudal annuli; (8) autotomy constriction on caudal annulus 7-10; (9) tail round in cross-section, with similar width along its length; (10) dorsal surface of tail with non-tuberculate segments; (11) tail tip round, segmented, not compressed; (12) 10-14 dorsal and 14-16 ventral segments on a midbody annulus (24-30 total midbody segments); (13) three supralabials; (14) three infralabials; (15) a pair of enlarged pentagonal parietals; (16) one postocular; (17) one temporal; (18) postmental distinctly longer than mental; (19) one or two rows of postgenials; (20) postmalar row present or absent; (21) dorsum and venter uniformly dark brown or light brown in preservative, with a white or a brown tail tip. Basic morphological data are present in Table 1, and photographs of the five known specimens are shown in Figures 1-4.

Diagnosis.

Among the Bolivian and Peruvian amphisbaenians (characters inside parenthesis) the round head distinguishes Amphisbaena slateri from A. kingii Bell, 1833, (keel-headed) and Leposternon microcephalum Wagler, 1824 (shovel-headed). The four precloacal pores distinguish it from A. silvestrii Boulenger, 1902 (two pores) and A. fuliginosa Linnaeus, 1758 (6-10 pores). The presence of 176-213 body annuli distinguishes A. slateri from A. borelli Peracca, 1897 (239-261), A. occidentalis Cope, 1876 (262-275), A. polygrammica Werner, 1900 (270), A. steindachneri Strauch, 1881 (255-266), and A. townsendi Stejneger, 1911 (261-279). By having 10-14 dorsal segments at midbody, A. slateri differs from A. alba (30-42), A. angustifrons Cope, 1861 (20-31), A. bolivica Mertens, 1929 (27-38), A. camura Cope, 1862 (28-42), A. cegei Montero, Sáfadez & Álvarez, 1997 (17-22), and A. vermicularis Wagler, 1824 (18-26). Amphisbaena slateri differs from A. heterozonata Burmeister, 1861 - sometimes considered a subspecies of A. darwinii Duméril & Bibron, 1839 ( Montero 2016) - by the having 20-24 caudal annuli (vs. 13-18), enlarged parietals (vs. rarely enlarged), and a uniform body coloration (vs. dorsum brown, venter cream). Despite a small overlap in midbody dorsal/ventral segment counts between A. slateri (10 –14/14– 16) and A. heterozonata (14 –24/15– 28), specimens of the later most commonly have 16/18 segments. Finally, A. slateri differs from A. pericensis Noble, 1921 by lacking a compressed tail tip (vs. slightly laterally compressed), by having a postmental longer than the mental (vs. postmental faintly longer than mental) and having a uniform body coloration (vs. dorsum brown, venter cream). A summary of morphological characters useful to identify Peruvian and Bolivian amphisbaenids is present in Table 2.

Expanding comparisons to all Neotropical amphisbaenians, we find an overlap of most morphological character states between A. slateri and A. albocingulata Boettger, 1885, A. darwinii Duméril & Bibron, 1839, A. hogei Vanzolini, 1950, A. manni Barbour, 1914, A. mensae Castro-Mello, 2000, A. munoai Klappenbach, 1960, A nigricauda Gans, 1966, A. prunicolor (Cope, 1885), A. schmidti Gans, 1964, and A. talisiae Vanzolini, 1995. The uniform color pattern of A. slateri distinguishes it from A. albocingulata , A. darwinii , A. hogei , A. mensae , A. munoai , A. nigricauda , A. schmidti , and A. talisiae (countershading pattern), and from A. prunicolor (venter with a checkerboard pattern). By presenting a modal number of 14 midbody ventral segments, Amphisbaena slateri differs from A. hogei , A. manni , A. munoai , A. nigricauda , A. prunicolor , and A. schmidti (16), A. albocingulata (18), and A. darwinii (20). While all known specimens of A. slateri have four precloacal pores, most specimens of A. manni have six pores - females of A. nigricauda and A. prunicolor lack pores, but this trait is unknown in A. slateri , since no specimen was sexed. Postmental is distinctly longer than wide in A. slateri , while it is almost long as wide in A. darwinii , A. mensae , A. munoai , A. nigricauda , A. prunicolor , and A. talisiae . Parietals are enlarged in A. slateri , but not in A. manni and are irregular in A. darwinii . Finally, while the tail tip is rounded in A. slateri , it is conical in A. manni and has a slight lateral constriction in A. darwinii , A. hogei , and A. nigricauda .

Distribution and habitat.

Amphisbaena slateri is known from southeastern Peru (Departamento Huánuco) to western Bolivia (Departamento La Paz) (Figure 5; Table 3). Locality records are in the Tropical and Subtropical Moist Broadleaf Forests biome (Ucayali Moist Forests, Southwest Amazon Moist Forests, and Bolivian Yungas ecoregions). The main soil types of the localities where the species is known are cambisol and regosol, with coarse (loamy sand or sandy loam) to medium textures (loam or silt loam).