# Characteristics and Phylogenetic Considerations of the Newly Sequenced Mitochondrial Genome of Teratoscincus scincus (Gekkota: Sphaerodactylidae)

## TL;DR

This paper reports the sequencing of the mitochondrial genome of Teratoscincus scincus and uses it to clarify its evolutionary relationships within the Sphaerodactylidae family.

## Contribution

The study provides the first complete mitochondrial genome of T. scincus and confirms its phylogenetic placement within the genus Teratoscincus.

## Key findings

- The mitochondrial genome of T. scincus is 16,943 bp long and has a high A + T content of 56.3% in protein-coding genes.
- Phylogenetic analysis shows T. scincus forms a monophyletic clade with T. keyserlingii, supporting its classification in the genus Teratoscincus.
- The study enriches the mitochondrial genomic database for Sphaerodactylidae and supports future research on adaptive evolution and conservation.

## Abstract

This study sequenced and analyzed the complete mitochondrial genome of Teratoscincus scincus using the Illumina NovaSeq Xplus platform. The circular mitogenome is 16,943 bp in length, comprising 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, and 1 control region. It exhibits a distinct AT preference, with the highest A + T content (56.3%) observed in the PCGs. Phylogenetic analysis based on 13 PCGs from 10 Sphaerodactylidae species confirmed that T. scincus belongs to the genus Teratoscincus, forming a monophyletic clade with Teratoscincus keyserlingii. This work enriches the mitochondrial genomic database for Sphaerodactylidae and lays a foundation for research on the adaptive evolution and conservation of T. scincus.

Sphaerodactylidae play a crucial role in ecosystems, possessing significant ecological, scientific, and conservation value. They contribute to pest control and the maintenance of ecological balance, and also provide abundant materials for research in evolutionary biology and biodiversity. To refine the phylogenetic position of Teratoscincus scincus within the Sphaerodactylidae using mitogenomic data, this study sequenced the complete mitochondrial genome of T. scincus using the Illumina NovaSeq Xplus platform, and subsequently performed assembly, annotation, and analysis. The phylogenetic relationships of T. scincus within the Sphaerodactylidae were analyzed using 13 protein-coding genes (PCGs) from the mitochondrial genome via Bayesian inference (BI) and maximum likelihood (ML) methods. The complete mitochondrial genome of T. scincus is 16,943 bp in length and consists of 13 PCGs, 22 tRNA genes, 2 rRNA genes, and 1 control region (D-loop). The base composition shows a distinct AT preference, with the highest A + T content (56.3%) found in the PCGs region. A phylogenetic tree was constructed based on the amino acid sequences of 13 PCGs from the mitochondrial genomes of nine Sphaerodactylidae species retrieved from GenBank and the newly sequenced T. scincus generated in this study. The results confirm that T. scincus belongs to the genus Teratoscincus within the family Sphaerodactylidae. Phylogenetic analysis reveals that T. scincus and Teratoscincus keyserlingii cluster into a monophyletic group, suggesting a close phylogenetic relationship. Additionally, the phylogenetic tree provides new molecular evidence for understanding the formation mechanism of Sphaerodactylidae diversity. This study not only enriches the mitochondrial genome database of Sphaerodactylidae but also lays an important foundation for subsequent research on the adaptive evolution and conservation biology of T. scincus.