An unknown segment number in centipedes: a new species of Scolopocryptops (Chilopoda: Scolopendromorpha) from Trinidad with 25 leg-bearing segments

• Published in: Organisms diversity & evolution 2023-06, Vol.23 (2), p.369-380
• Main Authors: Chagas-Jr, Amazonas, Edgecombe, Gregory D., Minelli, Alessandro
• Format: Article
• Language: English
• Subjects: Animal Systematics/Taxonomy/Biogeography; Biodiversity; Biomedical and Life Sciences; Developmental Biology; Evolutionary Biology; Leg; Life Sciences; New species; Original Article; Plant Systematics/Taxonomy/Biogeography; Plates; Reproduction (copying); Scolopendromorpha; Segments; Teeth; Vector-borne diseases
• ISSN: 1439-6092; 1618-1077
• DOI: 10.1007/s13127-022-00591-7

A new species of the widely distributed centipede genus Scolopocryptops Newport, 1845 is described from Trinidad based on light microscopic documentation. Scolopocryptops sukuyan n. sp. is remarkable for being the only centipede known to have 25 leg-bearing segments in the trunk. The new species resembles Scolocryptops melanostoma Newport, 1845 in the shape of the cephalic plate and the coxosternal tooth plates and resembles S. miersii Newport, 1845 in the process of the forcipular trochanteroprefemur. It differs from both by the number of leg-bearing trunk segments (25 vs 23) and lengths of the thickened chitinous bands on the tooth plates, coxopleural process, and spinous prefemoral processes. Its systematic position within Scolopendromorpha, in which all but one of ca 700 species have either 21 or 23 segments and this number is mostly constant within families, indicates a trend of segment addition from 21 to 23 to 25 in the lineage leading to the new species. A review of patterns of variation in segment numbers in centipedes suggests that the 23 to 25 shift in Scolopocryptops is a consequence of the production of one extra body unit prior to the duplication of primary trunk segmental units common to all centipedes. This differs from the dramatic difference (39 or 43 vs. 21 or 23 leg-bearing segments) separating the most polypodous scolopendromorph, Scolopendropsis duplicata  Chagas-Júnior et al. (Zootaxa 1888:36–46,  2008 ), from its closest relative, likely due to duplication (or splitting) of the whole set of trunk segments prior to duplication of the primary trunk segmental units.