Amphisbaena caetitensis

Variation. There was no striking variation within the type series, except by the presence of intercalated body annuli, which was only detected in MHNBA 190 and MHNBA 191. Other relevant variations within the type series are in Table 1. Comparison with other species. Characters from other species are in parenthesis. The presence of a modified tail distinguish the new species from all South American amphisbaenids, except Amphisbaena uroxena. The round head distinguish the new species from A. bagual Ribeiro, Santos & Zaher, 2015; A. cerradensis (Ribeiro, Vaz-Silva & Santos-Jr., 2008); A. infraorbitale (Bertold, 1859), A. kisteumacheri (Porto, Soares & Caramaschi, 2000); A. maxima (Ribeiro, Nogueira, Cintra, Silva-Jr. & Zaher, 2011); A. microcephala (Wagler, 1824); A. octostega (Duméril, 1851); A. polystega (Duméril, 1851); A. scutigera (Hemprich, 1820) and A. wuchereri (Peters, 1879) (shovel head). This character also distinguishes the new species from A. acrobeles (Ribeiro, Catro-Mello & Nogueira, 2009); A. bilabialata (Stimson, 1972), A. kingii (Bell, 1833), Mesobaena huebneri Mertens, 1925 and M. rhachicephala Hoogmoed, Pinto, da Rocha & Pereira, 2009 (keeled head). The presence of four precloacal pores diagnose the new species from A. anaemariae Vanzolini, 1997; A. brevis Strussmann & Mott, 2009; A. caiari Teixeira Jr, dal Vechio, Neto & Rodrigues, 2014; A. carli Pinna, Mendonça, Bocchiglieri & Fernandes, 2010; A. crisae Vanzolini, 1997; A. dubia Muller, 1924; A. filiformis Ribeiro, Gomes, Rodrigues da Silva, Cintra & da Silva, 2016; A. hiata Montero & Céspedez, 2002; A. leeseri Gans, 1964 a; A. maranhensis Gomes & Maciel, 2012; A. metallurga Costa, Resende, Teixeira, Vechio & Clemente, 2015; A. mitchelli Procter, 1923; A. miringoera Vanzolini, 1971; A. neglecta Dunn & Piatt, 1936; A. persephone Pinna, Mendonça, Bocchiglieri & Fernandes, 2014 and A. silvestrii Boulenger, 1902 (0 – 3 pores). This characteristic also differentiate it from A. fuliginosa Linnaeus, 1758; A. ignatiana Vanzolini, 1991 a; A. kraoh (Vanzolini, 1971); A. leucocephala Peters, 1878; A. littoralis Roberto, Brito & Ávila, 2014; A. mertensii Strauch, 1881; A. pretrei Duméril & Bibron, 1839 and A. stejnegeri Ruthven, 1922 (5 – 12 pores). Among the four-pored amphisbaenids, A. caetitensis sp nov. differs from A. bahiana Vanzolini, 1964; A. borelli Peracca, 1897; A. roberti Gans, 1964 b; A. steindachneri Strauch, 1881 and A. polygrammica Werner, 1901 by having 186 – 194 body annuli (> 204) and 10 – 12 tail annuli (> 14). Moreover, it differs from all remaining species by the absence of an autotomy site, except A. alba Linnaeus, 1758; A. angustifrons Cope, 1861; A. brasiliana (Gray, 1865); A. ridleyi Boulenger, 1890; A. saxosa (Castro-Mello, 2003) and A. uroxena. The new species differs from A. alba by having 186 – 194 body annuli (198 – 248), 10 – 12 tail annuli (13 – 21), 16 dorsal segments on a midbody annulus (30 – 42) and 19 – 22 ventral segments on a midbody annulus (35 – 46). In the same way, A. caetitensis sp nov. differs from A. ridleyi by having 10 – 12 tail annuli (14 – 17, Table 2). It differs from A. brasiliana and A. saxosa by having 186 – 194 body annuli (> 213), 16 dorsal segments on a midbody annulus (> 18) and in the sequential disposition of the precloacal pores which are separated by an area without pores in A. brasiliana and A. saxosa (Table 2). Additionally, it also differs from both species in the shape of rostral and nasals (large rostral and reduced nasals that do not contact at midline). Furthermore, A. caetitensis sp nov. differs from all species mentioned above, except A. uroxena, by having modified conic pointed tubercles on the tip of its tail. Finally, it differs from A. uroxena by having 186 – 194 body annuli (199 – 213), and 16 dorsal segments on a midbody annulus (12 – 14), 19 – 22 ventral segments on a midbody annulus (14 – 15, Table 2) and snout-vent length higher than 187 mm (<173 mm). Genetic distance. The final alignment resulted in a matrix of, 442 base pairs. Mean interspecific distance on the 16 S rRNA whitin Amphisbaenidae was 12.09 % while mean intraspecific distance was 1.34 %. Amphisbaena uroxena had the lowest genetic distance to A. caetitensis sp nov. (7.65 %, Supplementary Table S 1).

Diagnosis. A small Amphisbaena reaching up to 235 mm of total length. It is readily distinguished of its congeners by the presence of modified pointed scales on the tip of the tail visible on dorsal view, starting on the 7 – 8 th tail annulus; by having 186 – 194 body annuli; 0 – 2 intercalated body annuli; 10 – 12 tail annuli; 16 dorsal and 19 – 22 ventral segments on a midbody annulus (Table 1). Paired nasal, prefrontal, frontal and parietal shields in broad contact on the dorsal surface of the head; rostral shield slightly visible in dorsal view; three supralabials; three infralabials. Mental and post-mental scales present; post-mental scale followed by two rows of post-genial scales generally with two and three scales respectively. Dorsal and ventral sulci absent, lateral sulcus present, starting around the 45 th annulus. Four rounded pre-cloacal pores sequentially arranged; 6 – 7 pre-cloacal scales and 12 – 14 post-cloacal scales. Autotomy site absent. Coloration in preservative. Dorsal surface of the body raw umber (color 280; Kohler 2012); ventral surface pale buff (color 1), generally darker on the anterior portion of the body. Scales on the lateral of the body raw umber on the center and pale buff on the edges. Dorsal surface of the head raw umber posteriorly and olive brow (color 278) anteriorly. Ventral surface of the head pale buff.

Etymology. The name of the species refers to its type-locality, Caetité municipality, Bahia State, Brazil.

Holotype description. An immature male measuring 221 mm of snout-vent length and 14 mm of tail length. Body diameter 8.25 mm and tail diameter 8.28 mm. Head not distinct from neck, narrower than the body. Head width 5.62 mm and length 7.42 mm. Snout rounded; rostral slightly visible on dorsal view, subtriangular. Paired nasals, prefrontals, frontals and parietals in broad contact at midline. Nasals quadrangular, contacting the rostral anteriorly and the first supralabial ventrally. Prefrontals rectangular, the largest shields on the head representing 35.3 % of the head length (measured on the suture between the two prefrontal shields), in contact with nasal anteriorly, point contact with first supralabial, in contact with second supralabial and ocular ventrally and frontal, and marginally the postocular, posteriorly. Frontals almost trapezoid, representing 34.2 % of the head length, in contact with prefrontal anteriorly, point contact with ocular and broad contact with postocular ventrally and parietal posteriorly (Figure 2 A and D). Parietals hexagonal, 10.6 % of the head length, part of the second body annulus, in broad contact with frontal and postocular anteriorly. Oculars quadrangular, in broad contact with prefrontal anteriorly, point contact with frontal dorsally and temporal posteriorly, in broad contact with postocular posteriorly and second and third supralabials ventrally. Eyes barely visible, perceived as grayish spots (Figure 2 B and E). Three supralabials, the second slightly larger. First supralabial triangular, contacts the rostral anteriorly, in broad contact with the nasal and point contact with the prefrontal dorsally. Second supralabial pentagonal, broadly contacts the prefrontal and the ocular dorsally, point contact with nasal. Third supralabial pentagonal, contacts the ocular and largely the temporal dorsally and the first body annulus posteriorly (Figure 2 B and E). Three infralabials, second the largest. First infralabial trapezoid, in broad contact with mental anteriorly and postmental ventrally. Second infralabial pentagonal, largely contacting the postmental ventrally and malar posteriorly, point contact with first row of postgenials ventrally. Third infralabial quadrangular, in broad contact with malar ventrally and first body annulus posteriorly. Mental trapezoid, almost as long as wide, in broad contact with first infralabial laterally and postmental posteriorly. Postmental longer than wide, in broad contact with first and second infralabials laterally, followed by two rows of postgenials with two and three scales, respectively. Malar trapezoid, slightly wider than long, in broad contact with second infralabial anteriorly, third infralabial and two rows of postgenials laterally and first body annulus posteriorly; postmalars absent (Figure 2 C and F). One hundred and ninety-four body annuli, 11 tail annuli, intercalated body annuli absent, 16 dorsal and 20 ventral segments on a midbody annulus. Dorsal and ventral sulci absent, lateral sulcus present starting on the 45 th annulus. Four rounded and sequentially arranged precloacal pores; six precloacal and 14 postcloacal scales (Figure 3 A). Scales on the tip of tail modified in pointed tubercles starting on the eighth tail annulus, visible on lateral and dorsal views (Figure 3 B – C). Dorsal surface of body raw umber; ventral surface pale buff, darker on the anterior portion of the body; head olive brown anteriorly on the nasal and rostral shields, raw umber posteriorly; ventral surface pale buff.

Holotype. Immature male (MUFAL 13635), collected on April 25 – 27, 2017 at Fazenda do Engenho (13 ° 50 ’ 48 ” S, 42 ° 16 ’ 29 ” W), 854 m of elevation, in the municipality of Caetité, Bahia State, northeastern Brazil by AMP. Paratypes. Five specimens collected along with the holotype: MUFAL 13632, immature male; MHNBA 190, immature female; MHNBA 191, immature male; MUFAL 13633, immature female and MUFAL 1 3634, immature male. MUFAL 13636 was also collected at Fazenda do Engenho, about one kilometer away from the rest of the type series at 13 ° 51 ’ 16 ” S, 42 ° 16 ’ 37 ” W on May 02 – 31, 2017, sex undetermined; all collected by AMP.