Gothus teemo sp. nov. A–C. Holotype, male, CW 3.7 mm, CL 2.6 mm, MBM287027; D–F. Paratype, CW 3.2 mm, CL 2.2 mm, MBM287026; A, D. Dorsal view; B, E. Frontal view; C, F. Carapace. Scale bar: 1 mm.

Gothus teemo sp. nov. A, C, E. Holotype, male, CW 3.7 mm, CL 2.6 mm, MBM287027; B, D, F, G. Paratype, female, CW 3.2 mm, CL 2.2 mm, MBM287026; A. Male chelipeds; B. Female chelipeds; C. Male thoracic sternites; D. Female thoracic sternites; E. Male pleon; F. Female pleon; G. Female vulva. Scale bar: 1 mm (A–F); 0.2 mm (G).

Gothus teemo sp. nov. A–C, F, G–L. Holotype, male, CW 3.7 mm, CL 2.6 mm, MBM287027; D, E. Paratype, female, CW 3.2 mm, CL 2.2 mm, MBM287026; A. Carapace; B. Maxilliped 3; C. Cheliped; D. Pereopod 5; E. Female pleon; F. Male pleon; G. right G1, ventral view; H. Same, dorsal view; I. Right G1, distal part, ventral view; J. Same, dorsal view; K. Right G2, ventral view; L. Same, dorsal view. Scale bar: 1 mm (A, C, D); 0.5 mm (B, E, F, G, H); 0.1 mm (I–L).

Gothus teemo sp. nov. A, B. Holotype, male, CW 3.7 mm, CL 2.6 mm, MBM287027; C–E. Paratypes, 2 juvenile, CW 1.8–2.2 mm, CL 1.3–1.5 mm, MBM287023; A–D. Live coloration; E. Habitat and substrate conditions. Scale bar: 1 mm.

Gothus teemo sp. nov., paratype, female, CW 3.2 mm, CL 2.2 mm, MBM287026, artistic illustration, displaying live coloration. Drawn by Fei Gao.

Euxanthinae and Actaeodes species in comparative material. A. Rizalthus anconis Mendoza & PKL Ng, 2008, female; CW 4.2 mm, CL 2.7 mm, NS-MJ-2022-1457; B. Hypocolpus haanii Rathbun, 1909, 1 male, CW 45.3 mm, CL 34.2 mm, MBM286755; C. Euxanthus exsculptus (Herbst, 1790), 1 male, CW 52.6, CL 33.2 mm, MBM163793; D. Euxanthus huonii (Hombron & Jacquinot, 1846), CW 34.0 mm, CL 24.0 mm, NS-MJ-2022-1734; E. Psaumis cavipes (Dana, 1852), 1 male, CW 13.8 mm, CL 8.6 mm, aop01; F. Actaeodes mutatus Guinot, 1976, 1 female, CW 20.8 mm, CL 12.5 mm, BF02; G. Actaeodes hirsutissimus (Rüppell, 1830), 1 male, CW 31.9 mm, CL 21.0 mm, MBM164298; H. Actaeodes tomentosus (H. Milne Edwards, 1834), 1 male, CW 35.8 mm, CL 22.5 mm, Xan041. Scale bar: 1 mm (A); 5 mm (E, F); 10 mm (B–D, G, F).

Gothus consobrinus (A. Milne-Edwards, 1873), male, CW 6.7 mm, CL 4.4 mm, NS-YS-2022-1336. A. Dorsal habitus; B. Carapace; C. Frontal view; D. Thoracic sternites and pleon; E. Chelipeds. Scale bar: 2 mm.

Gothus consobrinus (A. Milne-Edwards, 1873), male, CW 6.7 mm, CL 4.4 mm, NS-YS-2022-1336. A. Carapace; B. Maxilliped 3; C. Cheliped; D. Pereopod 5; E. Pleon; F. Left G1, ventral view; G. Left G1; H. Left G2, ventral view. Scale bar: 2 mm (A); 0.5 mm (B, F, H); 1 mm (C, D, E); 0.1 mm (G).

Gothus consobrinus (A. Milne-Edwards, 1873). A–C. Female, CW 10.5 mm, CL 6.8 mm, MNHN-IU-2000-3885 (=MP-B3885S); D–F. Female, CW 8.8 mm, CL 5.7 mm, MNHN-IU-2024-3483; photographed by Sébastien Soubzmaigne; G–I. Female, CW 4.5 mm, CL 2.9 mm, XS-QL-2022-1014. Scale bar: 2 mm (A–F); 1 mm (G–I).

Gothus consobrinus (A. Milne-Edwards, 1873). A. Male, CW 6.7 mm, CL 4.4 mm, NS-YS-2022-1336; B. Female, CW 4.5 mm, CL 2.9 mm, XS-QL-2022-1014, displaying live coloration. Scale bar: 2 mm.

Phylogenetic relationships inferred from combined 12S, 16S, COI, and H3 sequences among Gothus gen. nov. and related species in Xanthidae, analyzed by Bayesian Inference (BI) and maximum likelihood (ML) analyses. A. BI tree, with posterior probabilities (PP) labeled; B. ML tree, with bootstrap replications (BS) labeled; values below 50 are hidden. Most data are derived from Lai et al. (2011) and Mendoza et al. (2022), as shown in Table 1.

Bayesian inference (BI) phylogenic tree based on COI showing the phylogenetic relationship between Gothus teemo sp. nov., G. consobrinus, and related Euxanthinae species, with bootstrap replications (BS) labeled and values below 50 not shown. The results of automated barcode gap discovery (ABGD) and Bayesian implementation of the Poisson tree processes (BPTP) species delimitation methods are shown on the right of the figure; each circle or capsule shape represents one species.