Amphisbaena amethysta, Ribeiro & Santos Jr & Martins & Oliveira & Graboski & Barbosa Da Silveira & Benício & Vaz-Silva, 2024

Ribeiro, Síria, Santos Jr, Alfredo P., Martins, Isabelly G., Oliveira, Elaine C. S., Graboski, Roberta, Barbosa Da Silveira, Thiago, Benício, Matheus H. M. & Vaz-Silva, Wilian, 2024, A new four-pored Amphisbaena Linnaeus, 1758 (Amphisbaenia, Amphisbaenidae) from the north of Espinhaço Mountain Range, Brazil, ZooKeys 1213, pp. 1-27 : 1-27

Amphisbaena amethysta sp. nov.

Figs 1 , 2 , 3 , 4

Type material.

Holotype: • male; CEPB 2311 ; municipality of Caetité , state of Bahia, Brazil; [14 ° 21 ' 31 " S, 42 ° 32 ' 19 " W; 1012 m above sea level (a. s. l.)]; collected on 1 November 2022 by Faunal Rescue Team Tecsam (F. Santos, P. Belufi, and G. Nascimento) . Paratypes: • All from Caetité , Bahia, Brazil; collected by Faunal Rescue Team Tecsam (R. Assunção, A. Hirota, T. Silveira, F. Santos, P. Belufi, and G. Nascimento) • Female; CEPB 2301 ; (14 ° 21 ' 53 " S, 42 ° 32 ' 20 " W; 1013 m a. s. l.); 8 June 2022 • Male; CEPB 2302 ; (14 ° 01 ' 16 " S, 42 ° 31 ' 06 " W; 1082 m a. s. l.); 13 October 2021 • Female; CEPB 2303 ; (14 ° 21 ' 50 " S, 42 ° 32 ' 20 " W; 1013 m a. s. l.); 26 May 2022 • Female; CEPB 2308 ; (14 ° 19 ' 49 " S, 42 ° 32 ' 44 " W; 1011 m a. s. l.); 8 September 2022 • Female; CEPB 2327 ; (14 ° 19 ' 52 " S, 42 ° 32 ' 42 " W; 1011 m a. s. l.); 1 October 2022 • Female; CEPB 2331 ; (14 ° 19 ' 45 " S, 42 ° 32 ' 45 " W; 1011 m a. s. l.); 30 August 2022 • Male; CEPB 2346 ; (14 ° 22 ' 08 " S, 42 ° 32 ' 17 " W; 923 m a. s. l.); 6 October 2022 • Male; CEPB 2379 ; (14 ° 21 ' 27 " S, 42 ° 32 ' 20 " W; 1033 m a. s. l.); 26 January 2023 • Female; CEPB 2381 ; (14 ° 21 ' 27 " S, 42 ° 32 ' 20 " W; 1033 m a. s. l.); 26 January 2023 .

Referred specimens.

All from Caetité , Bahia, Brazil; collected by Faunal Rescue Team Tecsam (R. Assunção, A. Hirota, T. Silveira, F. Santos, P. Belufi, and G. Nascimento) • Female; CEPB 2298 ; (14 ° 21 ' 53 " S, 42 ° 32 ' 20 " W; 1013 m a. s. l.); 8 June 2022 • Female; CEPB 2299 ; (14 ° 21 ' 53 " S, 42 ° 32 ' 20 " W; 1013 m a. s. l.); 8 June 2022 • Male; CEPB 2300 ; (14 ° 21 ' 51 " S, 42 ° 32 ' 21 " W; 1011 m a. s. l.); 25 May 2022 • Female; CEPB 2304 ; (14 ° 21 ' 53 " S, 42 ° 32 ' 20 " W; 1013 m a. s. l.); 8 June 2022 • Female; CEPB 2305 ; (14 ° 21 ' 53 " S, 42 ° 32 ' 20 " W; 1013 m a. s. l.); 8 June 2022 • Female; CEPB 2306 ; (14 ° 21 ' 53 " S, 42 ° 32 ' 20 " W; 1013 m a. s. l.); 13 August 2022 • Male; CEPB 2307 ; (14 ° 21 ' 23 " S, 43 ° 32 ' 07 " W; 972 m a. s. l.); 23 November 2022 • Undetermined sex; CEPB 2309 ; (14 ° 19 ' 46 " S, 42 ° 43 ' 20 " W; 1011 m a. s. l.); 1 September 2022 • Female; CEPB 2310 ; (14 ° 19 ' 55 " S, 42 ° 32 ' 44 " W; 1011 m a. s. l.); 8 October 2022 • Male; CEPB 2312 ; (14 ° 19 ' 56 " S, 42 ° 32 ' 43 " W; 1011 m a. s. l.); 12 October 2022 • Female; CEPB 2313 ; (14 ° 22 ' 08 " S, 42 ° 32 ' 17 " W; 9215 m a. s. l.); 6 October 2022 • Female; CEPB 2314 ; (14 ° 22 ' 08 " S, 42 ° 32 ' 17 " W; 925 m a. s. l.); 6 October 2022 • Female; CEPB 2315 ; (14 ° 22 ' 08 " S, 42 ° 32 ' 17 " W; 925 m a. s. l.); 6 October 2022 • Female; CEPB 2316 ; (14 ° 19 ' 47 " S, 42 ° 32 ' 43 " W; 1011 m a. s. l.); 1 September 2022 • Female; CEPB 2317 ; (14 ° 19 ' 55 " S, 43 ° 32 ' 44 " W; 1011 m a. s. l.); 1 October 2022 • Female; CEPB 2318 ; (14 ° 19 ' 46 " S, 42 ° 32 ' 43 " W; 1011 m a. s. l.); 1 September 2022 • Female; CEPB 2319 ; (14 ° 20 ' 37 " S, 42 ° 32 ' 13 " W; 1076 m a. s. l.); 3 August 2022 • Female; CEPB 2320 ; (14 ° 20 ' 38 " S, 42 ° 32 ' 12 " W; 1013 m a. s. l.); 2 June 2022 • Female; CEPB 2321 ; (14 ° 19 ' 53 " S, 42 ° 32 ' 43 " W; 1011 m a. s. l.); 29 September 2022 • Female; CEPB 2322 ; (14 ° 14 ' 28 " S, 42 ° 32 ' 47 " W; 842 m a. s. l.); 17 September 2022 • Female; CEPB 2323 ; (14 ° 19 ' 49 " S, 42 ° 32 ' 17 " W; 1062 m a. s. l.); 13 August 2022 • Male; CEPB 2324 ; (14 ° 19 ' 48 " S, 42 ° 32 ' 43 " W; 1011 m a. s. l.); 6 September 2022 • Female; CEPB 2325 ; (14 ° 19 ' 55 " S, 42 ° 32 ' 44 " W; 1011 m a. s. l.); 1 October 2022 • Male; CEPB 2326 ; (14 ° 20 ' 52 " S, 43 ° 32 ' 16 " W; 1053 m a. s. l.); 13 August 2022 • Female; CEPB 2328 ; (14 ° 21 ' 53 " S, 42 ° 32 ' 22 " W; 1011 m a. s. l.); 28 September 2022 • Male; CEPB 2329 ; (14 ° 19 ' 47 " S, 42 ° 32 ' 43 " W; 1011 m a. s. l.); 1 September 2022 • Male; CEPB 2330 ; (14 ° 19 ' 55 " S, 43 ° 32 ' 44 " W; 1011 m a. s. l.); 1 October 2022 • Male; CEPB 2332 ; (14 ° 20 ' 50 " S, 42 ° 32 ' 16 " W; 1057 m a. s. l.); 13 August 2022 • Female; CEPB 2333 ; (14 ° 14 ' 28 " S, 42 ° 32 ' 47 " W; 842 m a. s. l.); 17 September 2022 • Female; CEPB 2334 ; (14 ° 19 ' 46 " S, 42 ° 32 ' 43 " W; 1011 m a. s. l.); 1 September 2022 • Female; CEPB 2336 ; (14 ° 15 ' 11 " S, 45 ° 32 ' 16 " W; 987 m a. s. l.); 3 August 2022 • Female; CEPB 2337 ; (14 ° 20 ' 38 " S, 45 ° 32 ' 12 " W; 1076 m a. s. l.); 3 August 2022 • Female; CEPB 2338 ; (14 ° 21 ' 31 " S, 45 ° 32 ' 16 " W; 1010 m a. s. l.); 13 August 2022 • Female; CEPB 2339 ; (14 ° 14 ' 28 " S, 42 ° 32 ' 47 " W; 842 m a. s. l.); 17 September 2022 • Male; CEPB 2356 ; (14 ° 21 ' 27 " S, 42 ° 32 ' 21 " W; 1033 m a. s. l.); 1 November 2022 • Male; CEPB 2379 ; (14 ° 21 ' 27 " S, 42 ° 32 ' 20 " W; 1033 m a. s. l.); 26 January 2023 • Female; CEPB 2380 ; (14 ° 21 ' 27 " S, 42 ° 32 ' 20 " W; 1033 m a. s. l.); 26 January 2023 • Female; CEPB 2381 ; (14 ° 21 ' 27 " S, 42 ° 32 ' 20 " W; 1033 m a. s. l.); 26 January 2023 .

Diagnosis and comparisons with other south American amphisbaenians.

Amphisbaena amethysta sp. nov. is a medium-sized amphisbaenid (258 mm maximum snout-vent length), and can be distinguished from its congeners by the following combination of characters (see details in Table 1 ): (1) snout convex in profile view, slightly compressed not keeled; (2) pectoral scales arranged in regular annuli; (3) four precloacal pores; (4) distinct cephalic shields; (5) 185–199 dorsal half-annuli; (6) 13–16 caudal annuli; (7) conspicuous autotomic site between 4 th – 6 th caudal annuli; (8) 16–21 dorsal and ventral segments at midbody; (9) 3 / 3 supralabials; (10) 3 / 3 infralabials; and (11) smooth and rounded tail tip.

Amphisbaena amethysta sp. nov. differs from Amphisbaena acrobeles ( Ribeiro, Castro-Mello & Nogueira, 2009) , A. bilabialata (Stimson, 1972) , A. kingi (Bell, 1833) , A. anomala , Mesobaena huebneri Mertens, 1925 ; M. rhachicephala Hoogmoed, Pinto, Rocha & Pereira, 2009 ; and all Leposternon species, mainly in having the snout convex in profile view, slightly compressed not keeled (vs snout hardly compressed forming a sharp and prominent keel or snout depressed shovel-like). Differs still from A. anomala and all Leposternon species by having pectoral scales arranged in regular annuli (vs pectoral scales with an irregular form, and dermal annuli not regularly arranged).

Amphisbaena amethysta sp. nov. presents four precloacal pores, differing from all Amphisbaena species except A. acangaoba Ribeiro, Gomides & Costa, 2020 , A. alba , A. albocingulata Boettger, 1885 , A. angustifrons Cope, 1861 , A. arda , A. arenaria , A. arenicola Perez & Borges-Martins, 2019 , A. bahiana , A. bakeri Stejneger, 1904 , A. barbouri Gans & Alexander, 1962 , A. bedai ( Vanzolini, 1991) , A. bolivica Mertens, 1929 , A. borellii Peracca, 1897 , A. brasiliana (Gray, 1865) , A. caeca Cuvier, 1829 , A. camura Cope, 1862 , A. carlgansi Thomas & Hedges, 1998 , A. carioca Rocha, Barros-Filho & Sluys, 2023 , A. carvalhoi , A. caudalis Cochron, 1928 , A. cayemite Thomas & Hedges, 2006 , A. cegei Montero, Sáfadez, Álvarez, 1997 , A. cubana Gundlach & Peters, 1879 , A. cuiabana ( Strüssmann & Carvalho, 2001) , A. cunhai Hoogmoed & Ávila-Pires, 1991 , A. darwini , A. elbakyanae Torres-Ramírez, Angarita-Sierra & Vargas-Ramírez, 2021 , A. fenestrata (Cope, 1861) , A. frontalis , A. gonavensis Gans & Alexander, 1962 , A. gracilis Strauch, 1881 , A. hastata , A. heathi , A. hogei Vanzolini, 1950 , A. hoogmoedi Oliveira, Vaz-Silva, Santos-Jr, Graboski, Teixeira Jr, Dal Vechio & Ribeiro, 2018 , A. hyporissor Thomas, 1965 , A. innocens Weinland, 1862 , A. kingi , A. kraoh (Vanzolini, 1971) , A. leali Thomas & Hedges, 2006 , A. lumbricalis , A. manni Barbour, 1914 , A. medemi Gans & Mathers, 1977 , A. metallurga , A. mongoyo , A. munoai Klappenbach, 1960 , A. myersi Hoogmoed, 1989 , A. nana Perez & Borges-Martins, 2019 , A. nigricauda Gans, 1966 , A. occidentalis Cope, 1875 , A. pericensis Noble, 1921 , A. plumbea Gray, 1872 , A. polygrammica Werner, 1901 , A. prunicolor (Cope, 1885) , A. ridleyi Boulenger, 1890 , A. rozei Lancini, 1963, A. sanctaeritae Vanzolini, 1994 , A. saxosa (Castro-Mello, 2003) , A. schmidti Gans, 1964 , A. slateri Boulenger, 1907 , A. slevini Schmidt, 1936 , A. spurrelli Boulenger, 1915 , A. steindachneri Strauch, 1881 , A. supernumeraria Mott, Rodrigues & Dos Santos, 2009 , A. talisiae Vanzolini, 1995 , A. tyaraju, Perez & Borges-Martins, 2019 , A. townsendi Stejneger, 1911 , A. tragorrhectes Vanzolini, 1971 , A. uroxena , A. vanzolinii Gans, 1963 , A. vermicularis , and A. xera Thomas, 1966 .

Amphisbaena amethysta sp. nov. differs from Amphisbaena species with four precloacal pores mainly by following combination of meristic characters (Table 1 ): cephalic shield distinct (vs frontals and parietals shields not distinct in A. supernumeraria , ocular and second supralabial not distinct in A. cubana ); snout slightly compressed (vs hard compressed in A. kingi and rounded in all other species, except A. kraoh , A. brasiliana , A. bahiana , A. bedai , and A. saxosa ); 185–199 dorsal half-annuli (vs <170 annuli in A. cayemite and> 200 annuli in A. acangaoba , A. arda , A. arenaria , A. bahiana , A. bakeri , A. barbouri , A. bedai , A. borellii , A. brasiliana , A. caeca , A. carlgansi , A. carvalhoi , A. cayemite , A. cuiabana , A. cunhai , A. elbakyanae , A. fenestrata , A. frontalis , A. gonavensis , A. gracilis , A. hastata , A. hoogmoedi , A. kingi , A. kraoh , A. lumbricalis , A. manni , A. medemi , A. mongoyo , A. munoai , A. myersi , A. nigricauda , A. occidentalis , A. plumbea , A. polygrammica , A. rozei , A. sanctaeritae , A. saxosa , A. slevini , A. spurrelli , A. steindachneri , A. supernumeraria , A. talisiae , A. tyaraju , A. townsendi , A. uroxena , A. vanzolinii , A. vermicularis , and A. xera ); 13–16 caudal annuli (vs> 16 annuli in A. albocingulata , A. arda , A. arenaria , A. arenicola , A. bedai , A. bolivica , A. borellii , A. carvalhoi , A. caudalis , A. cegei , A. cuiabana , A. cunhai , A. darwini , A. elbakyanae , A. frontalis , A. gracilis , A. hastata , A. hoogmoedi , A. leali , A. lumbricalis , A. manni , A. medemi , A. metallurga , A. mongoyo , A. munoai , A. myersi , A. nana , A. nigricauda , A. occidentalis , A. polygrammica , A. prunicolor , A. rozei , A. sanctaeritae , A. saxosa , A. schmidti , A. slateri , A. slevini , A. spurrelli , A. steindachneri , A. supernumeraria , A. talisiae , A. tyaraju , A. townsendi , A. tragorrhectes , and A. vermicularis ); conspicuous autotomic site between 4 th – 6 th caudal annuli (vs absent in A. acangaoba , A. alba , A. angustifrons , A. bakeri , A. barbouri , A. brasiliana , A. carioca , A. carlgansi , A. cayemite , A. cunhai , A. fenestrata , A. gonavensis , A. hastata , A. hoogmoedi , A. innocens , A. lumbricalis , A. occidentalis , A. ridleyi , A. saxosa , and A. uroxena ; or from the 7 th caudal annuli in A. albocingulata , A. arda , A. arenicola , A. carvalhoi , A. cegei , A. cuiabana , A. darwini , A. heathi , A. kingi , A. metallurga , A. mongoyo , A. myersi , A. nana , A. prunicolor , A. schmidti , A. slateri , A. steindachneri , A. supernumeraria , A. talisiae , A. tyaraju , A. townsendi , A. tragorrhectes , and A. vanzolinii ), smooth and rounded tail tip [vs bluntly ridged tail tip in A. bahiana ; slightly dorsally compressed in A. acangaoba ; with tubercles sit is depressed (compressed dorsoventrally) in A. uroxena ; with modified conic pointed tubercles in A. caetitensis ; and vertically keeled in A. borellii and A. steindachneri ]; 16–21 dorsal segments at midbody (vs <16 in A. albocingulata , A. arenaria , A. arenicola , A. barbouri , A. carlgansi , A. carvalhoi , A. cayemite , A. cuiabana , A. elbakyanae , A. fenestrata , A. heathi , A. hogei , A. elbakyanae , A. metallurga , A. munoai , A. nana , A. nigricauda , A. sanctaeritae , A. schmidti , A. slateri , A. slevini , A. supernumeraria , A. talisiae , A. tyaraju , A. tragorrhectes , A. uroxena , and A. vanzolinii ); and> 21 segments in A. alba , A. arda , A. bolivica , A. camura , A. hoogmoedi , and A. kraoh ); 16–21 ventral segments at midbody (vs <16 in A. rozei , A. sanctaeritae , and A. tragorrhectes ; and> 21 segments in A. alba , A. arda , A. bolivica , A. camura , A. cegei , A. gonavensis , A. hyporissor , A. kraoh , A. occidentalis , and A. townsendi ); 3 / 3 supralabials (vs 2 / 2 in A. slevini and A. vanzolinii ; and 4 / 4 in A. acangaoba , A. alba , A. angustifrons , A. arda , A. arenaria , A. bedai , A. camura , A. cayemite , A. occidentalis , A. plumbea , A. ridleyi , A. saxosa , A. townsendi , A. tragorrhectes , and A. vermicularis ); and 3 / 3 infralabials (vs 2 / 2 in A. slevini and A. vanzolinii ; and or 4 / 4 in A. occidentalis , A. plumbea , A. ridleyi , A. saxosa , A. townsendi , and A. tragorrhectes ).

Description of the holotype.

medium-sized specimen; snout-vent length 233 mm plus 0.50 mm of cloacal portion; tail length 21.24 mm, representing 9.1 % of snout-vent length; midbody diameter 8.2 mm (3.5 % of snout-vent length); head relatively small, 6.90 mm (~ 2.9 % of snout-vent length); snout compressed in dorsal view and slightly convex in profile view, hardly keratinised, rostrum projecting forward beyond the jaw (prognathous). Anterior portion of body is slightly narrower. Rostral subtriangular, visible in dorsal and ventral view (Fig. 1 ), almost as high (2.21 mm) as wide (2.11 mm), in contact with nasal and first supralabial lateroposteriorly. Nasals subrectangular, aligned at the midline (1.00 mm suture) (Fig. 1 A ), almost as long (2.05 mm) as wide (1.99 mm), in contact with first supralabial laterally and prefrontals posteriorly, with nostrils placed near the antero-inferior angle of the nasal shield (Fig. 1 B ).

Prefrontals paired, relatively large (41.6 % of head length), with a shorter middorsal suture (2.01 mm; 29.3 % of head length), longer than the nasal middorsal suture (1.00 mm, 14.6 % of head length), almost as long as frontal middorsal suture (2.10 mm, 30.6 % of head length), anterior border convex, lateroposterior portion projected, in contact with second supralabial and ocular laterally, frontals posteriorly and in point contact with postocular posteriorly (Fig. 1 A ). Frontals subtriangular, longer (suture length) than wide (1.58 mm), aligned at midline (2.10 mm), in narrow contact with the oculars, and in broad contact posterolaterally with the postocular and parietal. Parietals in two larger irregulars segments, wider (1.48 mm) than long (1.04 mm), intercalated by four very smalls segments; not aligned at the midline, in narrow contact with postoculars laterally, and followed by the first dorsal half-annulus. Occipitals absent (Fig. 1 A ). Oculars almost diamond-shape, almost as long (1.57 mm) as high (1.51 mm), in contact with prefrontals and second supralabial anteriorly, third supralabial and postocular posteriorly, and in point contact with postsupralabial. Eyes slightly visible. Postocular longer than wide, sub-pentagonal, in contact with frontal, labial, parietal and the segments of the first dorsal half-annulus, and in point contact with prefrontal. Temporal subrectangular, higher (1.55 mm) than long (0.92 mm), in contact with third supralabial anteriorly, postocular and postsupralabial laterally and first dorsal half-annulus posteriorly (Fig. 1 B ).

Three supralabials, irregularly polygonal; first subtrapezoid, longer (2.05 mm) than high (1.50 mm), in contact with second supralabial posteriorly; second supralabial sub-pentagonal, higher (1.76 mm) than long (1.59 mm maximum length), in contact with prefrontal, ocular and third supralabial; third supralabial subtrapezoid, almost as high (1.37 mm) as long (1.24 mm), in contact with ocular and postsupralabial. Postsupralabial subquadrangular, representing almost 50 % of third supralabial high, in contact with temporal laterally and first half-annulus posteriorly (Fig. 1 B ). Mental longer (1.72 mm) than wide, anterior border wider (1.72 mm) than posterior (1.08 mm), in contact with the first pair of infralabials and postmental. Postmental longer (2.01 mm) than wide (1.65 mm), in contact with the first and second infralabial, narrowly with malar, and two anterior postgenials. Postgenials with five shields irregularly distributed, in contact with malars and first ventral half-annuli (Fig. 1 C ).

Three infralabials, first medium sized, irregular polygonal, almost as long (1.55 mm) as wide (1.56 mm), in contact with second supralabial; second the largest, sub-pentagonal, wider (2.36 mm) than long (1.81 mm maximum length), in contact with third infralabial; third infralabial smallest, almost as long (1.24 mm) as wide (1.37 mm) (Fig. 1 C ).

Body annuli well demarcated, first and second annuli without enlarged dorsal segments. Segments become regularly rectangular toward posterior portion of body and progressively longer than wide, and smaller in size, and larger towards midventral areas starting from the fifth half-annulus. One hundred ninety-four dorsal and 195 ventral half-annuli, three lateral half-annuli, 14 caudal annuli plus tip rounded; tail relatively long with autotomy line on the fifth annulus, 18 / 18 dorsal and ventral segments at midbody, respectively and 28 segments in fourth caudal annulus. Lateral sulci clearly visible from the forty-ninth annulus; dorsal and ventral sulci absent. Cloacal plate with six segments increasing in size from towards midline, eleven postcloacal segments; four precloacal pores strongly visible on the row of segments on the last ventral half-annulus; each pore placed on the posterior half of a single segment, and distributed along a continuous series of segments, but pores in the medial scales placed laterally (Fig. 2 ).

Intraspecific variation.

The main variations in the type series for meristic and morphometric data are given in Table 2 . Variation in the arrangement and contact of shields were also observed. CEPB 2280 presents frontal fused with the parietal and segments of first and second body annuli (Fig. 3 A ), CEPB 2309 present four parietals shields (Fig. 3 B ), and CEPB 2303 present supralabials fused in left side (Fig. 3 C ).

Colour in life.

Dorsum and lateral parts with dark brown coloration on the segments, which is more pronounced in the vertebral (Fig. 4 A ) and dorsal section of the tail regions (Fig. 4 B ). Pink predominates in areas where the brown colour is less pronounced. We do not have photographs of the ventral region of the live specimen.

Colour in preservative

(ethylic alcohol 70 %). Dorsum cream, with brown colouring on the segments in the dorsum, lateral parts, and dorsal portions of the tail portions. Dorsal, lateral, and ventral portions of head pale brown, darker than the ventral portion. Venter cream coloured.

Etymology.

The specific epithet refers to the mineral amethyst that is a type of quartz and also the name of the region of the type locality “ Brejinho das Ametistas ”, a district located south of the municipality of Caetité, state of Bahia. This region has been an amethyst mining centre since the beginning of the 20 th century. Spix and Martius (1938) defined the mineral from the “ Brejinho das Ametistas ” mines as “ the beautiful amethysts ” on their trip through the “ Alto Sertão ” of Bahia at the beginning of the 19 th century ( Cotrim 2015). The region currently has an economy based on mining and energy activities focused on wind energy production. The type series was collected during the execution of environmental programs within the scope of Bahia Mineração ( BAMIN), which operates in the exploration of iron ore in the “ Brejinho das Ametistas ” region.

Distribution and habitat.

Amphisbaena amethysta sp. nov. is known from municipality of Caetité municipality, state of Bahia, Brazil (Fig. 5 ). The region is in the northern portion of the Espinhaço Mountain Range, has an average altitude of 1000 m a. s. l., and lies within the ecotone between two morphoclimatic domains, Caatinga and Cerrado. In the region there are patches of deciduous and semi-deciduous forests [“ Floresta Estacional Decidual ” and “ Floresta Semidecidual Montana ” sensu IBGE (2023)] associated with valleys, slopes, and gallery forests, and containing floristic elements common to the vegetation of the Caatinga, Cerrado, and Atlantic Forest morphoclimatic domains. Areas of savannah vegetation with rock outcrops, typical of the woody Caatinga, occur at higher elevations (Fig. 6 ).

Phylogenetic relationships.

Our concatenated alignment totalled 4806 base pairs (1007 bp for 12 S, 528 bp for 16 S, 761 bp for nd 2, 679 bp for bdnf, 574 bp for c-mos, and 1257 bp for rag 1). Partition Finder identified a best-fit scheme composed of ten partitions with the GTR + G model. The resulting ML topology (Fig. 7 ) for the higher-level affinities was similar to those reported by previous studies ( Mott and Vieites 2009; Longrich et al. 2015; Graboski et al. 2022) (Fig. 7 ). Amphisbaena amethysta sp. nov. was recovered as a sister group of A. caetitensis , with 92 % of bootstrap support. The clade composed by Amphisbaena amethysta sp. nov. and A. caetitensis was recovered as a sister group of A. angustifrons , A. darwini , A. kingi , A. leeseri , and A. munoai with low bootstrap support (21 %). The genetic distance (p-distance) between Amphisbaena amethysta sp. nov. and A. caetitensis is 6.1 % for 16 S.

Figures

Figure 1. Amphisbaena amethysta sp. nov. (Holotype, CEPB 2311) A dorsal B lateral, and C ventral views of head. Scale bar: 3 mm.

Figure 2. Tail of Amphisbaena amethysta sp. nov. (Holotype, CEPB 2311). Detail of the autotomic site and four precloacal pores. Scale bar: 3 mm.

Figure 3. Amphisbaena amethysta sp. nov. in life (not identified specimen of type series) A lateral view and B dorsal. Photograph by T. B. S.

Figure 4. Variation (grey in the drawings) of cephalic shields of Amphisbaena amethysta sp. nov. A dorsal view of the head of CEPB 2280 with frontal variation B dorsal view of CEPB 2309 with four parietal shields, and C lateral view of left side of CEPB 2303 (paratype) with supralabials fused. Scale bar: 3 mm.

Figure 5. Geographic distribution of Amphisbaena amethysta sp. nov. and others Amphisbaena species from Espinhaço Mountain Range locality. Black arrows indicate the type localities of the species with more than one known geographic record.

Figure 6. Caatinga site where the holotype of Amphisbaena amethysta sp. nov. was collected in the in the northern portion of Espinhaço Mountain Range, in state of Bahia, Brazil.

Figure 7. Maximum likelihood tree zoomed in Central and South American Amphisbaenidae resulting from the RAxML analysis based on six concatenated genes, three nuclear (BDNF, c-mos, and RAG 1), and three mitochondrial (12 S, 16 S, and ND 2) genes. Red branches denote the clade composed of the new species and its sister species. Numbers on branches represent bootstrap values RAxML (> 70 %). The grey codes on the right side of the clades represent the South American subclades of Amphisbaena (G 01 – G 09) and West Indies clades (WIC 01 – WIC 02).