Spiny centipede (Scolopendra spinosissima) differs from paradox centipede (Scolopendra paradoxa)

NEWS - Recent description of scolopendromorph centipede, paradox centipede (Scolopendra paradoxa Doménech 2018), raises questions about morphological limits of its closest relative spiny centipede (Scolopendra spinosissima Kraepelin 1903). Carles Doménech of the Universitat d’Alacant in Spain, redescribed S. spinosissima and compared with type material of S. paradoxa.

Centipedes, class Chilopoda, are one of the most widespread groups of terrestrial arthropods in the world, with predatory activity occurring predominantly at night. There are a total of 3300 extinct and extant taxa in five distinct orders.

The Scolopendromorpha, which accommodates Scolopendra Linnaeus 1758, includes ~100 species. In the Philippines, Scolopendra currently comprises 6 valid taxa, 3 of which are endemic. S. spinosissima is dark red to brownish in color. Antennae reaching posterior border of T3, rarely T4; with 19 antennal articles, four basal glabrous.

Paramedian sutures on tergites very variable in TT1-7, complete in TT8-20. Paramedian sutures on sternites incomplete in SS 2-20. Free edge of coxopleuron not extending beyond posterior edge of T21. Coxopleural process moderately long and not kinked with coxopleuron, forming an angle of ~120 degrees.

Coxopleural process with one AP and one smaller dorsal SAP, rarely with extra ventral SAP. Prefemur UL with single spine tip, long spinous processes located in VL: 1, V: 2, VM: 2, M: 1, DM: 2, and SP: 1. Penis, gonopods, and secondary sexual characteristics absent in males. This species has a Philippine distribution and is endemic. Known from Luzon, Cebu, Negros, Guimaras and Panay.

S. paradoxa can be distinguished from S. spinosissima by antennae usually reaching T5 (vs. T3, rarely T4); the first four basal antennal articles are glabrous dorsally and the first 5-5.5 glabrous ventrally (vs. four basal glabrous over the entire surface). The surface of the cephalic plate is covered only by scattered small puncta anteriorly (vs. the entire cephalic plate is covered by rare small puncta).

The free margin of the coxopleuron is very long, clearly extending beyond the posterior margin of T21 (vs. coxopleuron reaching but not extending beyond T21); the posterodorsal margin of the coxopleuron forms an angle of ~180° with the dorsal margin of the coxopleural process (vs. ~120 degrees in S. spinosissima). Coxopleural process elongate and large, with two spines (vs. short and smaller, with two or rarely three spines).

Prefemoral spinous UL with seven very long and narrow basal processes; spines nearly straight, consistently two in VL, zero in V, and only one in VM (vs. nine much shorter spinous processes with broad bases, and with spines slightly curved backward, consistently with one distal process in VL and with two each in V and VM).

Legs with one tarsal spur in 1-18, rarely 1-19 (vs. commonly 1-20); distinct aposematic coloration, with orange antennae, dichromatic orange, yellowish, or dark green tergites anteriorly, and dark blue or brown posteriorly, legs greenish blue (vs. less distinct aposematic coloration, with monochromatic brownish or dark red tergites, and with orange antennae and legs); size up to 176 mm (vs. up to 147 mm).

Semiaquatic behavior (vs. exclusively terrestrial lifestyle) and partial cytochrome c oxidase (COI) sequence genetic distances between 18.2-19.6%. Furthermore, S. spinosissima and also S. paradoxa can be distinguished from all remaining relatives in Southeast Asia and also from all species in the genus Scolopendra by the paramedian sutures being interrupted exclusively on the TT and SS, and by the unique shape, size, and disposition of the spinous processes of the UL.

Repeated misidentification of historical specimens of S. spinosissima as S. multidens suggests that the presence of this taxon in the Philippines should be reconsidered. S. multidens has only been reported from southwest continental Asia, Java (Indonesia) and doubtfully from New Guinea.

The taxonomic assessment of these two Scolopendra species is a major step towards increasing knowledge of their biodiversity and developing conservation strategies involving these venomous arthropods with potential for agricultural and pharmaceutical applications.

Original research

Doménech C. (2024). Type designation and redescription of Scolopendra spinosissima Kraepelin, 1903 (Scolopendromorpha, Scolopendridae), with remarks on related taxa. ZooKeys 1215: 311-334, DOI:10.3897/zookeys.1215.129410

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