New living fossil, Amethyst worm lizard (Amphisbaena amethysta), from Espinhaço Mountain Range, Brazil

NEWS - New species from the northern Espinhaço Mountains, Caetité municipality, Bahia state, Brazil. Amethyst worm lizard (Amphisbaena amethysta) is the 71st species of the genus with 4 precloacal pores and the 22nd species of Caatinga morphoclimatic domain. Identification of the new species shows the reptiles of the Mountains are far from complete and may contain greater diversity of endemic taxa.

A. amethysta can be distinguished by its anteriorly convex snout, slightly compressed and unkeeled, pectoral scales arranged in regular annuli, four precloacal pores, distinct head shield, 185-199 dorsal and half annuli, 13-16 caudal annuli, a conspicuous autotomy spot between the 4th-6th caudal annuli, 16-21 dorsal and ventral segments in the middle of the body, 3/3 supralabials, 3/3 infralabials and a smooth and rounded tail tip.

A. amethysta occurs in areas with an average elevation of 1000 meters in patches of deciduous and semi-deciduous forests associated with valleys, slopes, forests and containing floristic elements. Areas of savanna vegetation with rocky outcrops, typically woody at higher elevations.

The distribution pattern is similar to that of five other Amphisbaena species restricted to the highland areas of the Espinhaço Mountains in Bahia (A. bahiana, A. longinqua, A. metallurga, A. mongoyo, A. uroxena) of which four are phylogenetically closely related, but do not show a close phylogenetic relationship with A. amethysta.

The other three species do not show a clear relationship with the species from the Espinhaço Mountains but also occur at the same elevation and vegetation type (A. kiriri, A. acangaoba and A. ignatiana).

The researchers sequenced a total of 4806 base pairs and the new species is a group of A. caetitensis with 92% bootstrap. The clade composed by A. amethysta and A. caetitensis was found to be a group of A. angustifrons, A. darwini, A. kingi, A. leeseri and A. munoai with a low bootstrap (21%). The genetic distance between A. amethysta and A. caetitensis is 6.1%.

The specific epithet refers to the mineral amethyst which is a type of quartz and also the name of the type site “Brejinho das Ametistas”, a district located in the south of the municipality of Caetité, Bahia state. This area has been a center of amethyst mining since the beginning of the 20th century.

Mining activities cause several irreversible environmental changes, including habitat loss due to vegetation clearing, relocation and excavation during the opening and operation of new mines. These actions have a direct impact on terrestrial and fossil species such as amphibians.

Original research

Ribeiro S, Santos Jr AP, Martins IG, Oliveira ECS, Graboski R, Barbosa Da Silveira T, Benício MHM, Vaz-Silva W (2024). A new four-pored Amphisbaena Linnaeus, 1758 (Amphisbaenia, Amphisbaenidae) from the north of Espinhaço Mountain Range, Brazil. ZooKeys 1213: 1-27, DOI:10.3897/zookeys.1213.122265

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