Strigamia crassipes (C.L Koch, 1835)

Bonato, Lucio, Bortolin, Francesca, Zen, Giada De, Decker, Peter, Lindner, E. Norman, Orlando, Marco, Spelda, Jörg & Wesener, Karin Voigtländer and Thomas, 2023, Towards elucidating species diversity of European inland Strigamia (Chilopoda: Geophilomorpha): a first reassessment integrating multiple lines of evidence, Zoological Journal of the Linnean Society 199 (4), pp. 945-966 : 957-961

Strigamia crassipes (C.L Koch, 1835) species complex

Diagnosis of adult individuals: Usually ≤ 4 cm long, but in some lineages ≤ 2 cm and in other lineages ≤ 6 cm long; clypeal setae uniformly spaced in a continuous array, without recognizable gaps between intermediate and lateral groups of setae; forcipular tergite usually 35–50% of the length of the head; forcipules variable in size and separation, usually moderately separated (distance between the basal condyles 1.5–2.0 times the basal width of the forcipules); forcipular tibia usually with a distinct projection; tarsungulum moderately elongate (usually 70–80% of the distance between the basal forcipular condyles, on average 75%), with the outlines of the intermediate part (i.e, basal part of the ungulum) fully converging; forcipular denticle of moderate length (usually 50–60% of the tarsungulum length, on average 55%) and its outlines distinctly curved; variable number of leg pairs, any odd number in the range 37–65, more frequently 47–49 in females and 45–47 in males; metasternites of the anterior one-third of the trunk without a mid-longitudinal sclerotized stripe, only a shallow groove; each coxopleuron with relatively few coxal pores in proportion to body size, i.e. usually no more than 15 pores in individuals ≤ 25 mm long, and no more than 25 pores in longer individuals; coxal pores relatively large in proportion to body size, diameter of the largest pore usually> 4% of the head width, and usually about as wide as their canals.

Geographical range: Within the study area, species of the S. crassipes complex are widespread from the northern coastal plain, through the entire Alps to Corsica and the Apennines, then southwards to the Nebrodi mountains in Sicily ( Fig. 8 ). They are missing from Sardinia.

Outside the study area, the distribution of species of the S. crassipes complex needs deep revision, because of the broad variation of taxonomic opinions and nomenclature used by different authors (see below, under Discussion; Supporting Information, Appendix). Most published records cannot be interpreted confidently as referring to either the S. carniolensis complex or the S. crassipes complex. Those that can be assigned confidently to the S. crassipes complex indicate that species of this complex inhabit a broad area in Central and Eastern Europe: westwards at least to the Provence Prealps ( Iorio and Berg 2007, sub S. transsilvanica ; see below, under Discussion; Supporting Information, Appendix), the Meuse river ( Iorio 2014, sub S. transsilvanica ; Jeekel and Brugge 2009) and Great Britain (original; Fig. 4 ); northwards to the southern part of the Scandinavian Peninsula ( Porat 1889, Andersson et al. 2008) and the lands east of the Baltic Sea ( Bonato et al. 2005, 2012, given as uncertain, sub S. transsilvanica , but here confirmed; Sammet et al. 2018, sub S. transsilvanica ); eastwards at least to the Carpathians ( Verhoeff 1935, sub Scolioplanes transsilvanicus ; Matic and Dărăbanţu 1968, sub S. transsilvanica ); and southwards to the Peloponnese ( Zapparoli 1994, sub S. transsilvanica ). Other published records from other areas have been questioned (e.g. Bonato et al. 2012) or need confirmation, including recent records from the Azores (e.g. Borges and Enghoff 2005, Borges et al. 2016) and from European Russia ( Zuev and Evsyukov 2016).

Candidate species: Different lines of evidence indicate at least three species.

One candidate species ( Fig. 4Aʹ 3) differs from other species of the same complex by a remarkably shorter body (rarely> 20 mm) and fewer body segments (39–43 leg pairs in females and 37–41 leg pairs in males). It seems to be distributed along the Western Alps and the northern Apennines, between the Pennine Alps and the northernmost part of the Tuscan-Emilian Apennines, as well as in Corsica ( Fig. 8 ). No names are available for this species.

Another candidate species (Aʹ 2) differs from other species of the same complex by a remarkably longer body (> 40 mm) and more numerous body segments (55–65 pairs in both sexes). It seems to be distributed in a narrower part of the south-western Alps, between the Coưian and the Ligurian Alps ( Fig. 8 ). It is already distinguished as S. cottiana (for detailed notes on the nomenclature, see Supporting Information, Appendix).

Figures

Figure 4. Hypotheses of species delimitation of Strigamiaobtained from different lines of evidence and different methods, illustrated upon the ultrametric tree of the COI. Bootstrap values are indicated whenever different from 100%. Tree tips represent haplotypes, coded as in the Supporting Information (Table S3). Both the previous species identification of the specimens and the revised names of the species complexes are indicated. Intraspecific genetic distances are given in the Supporting Information (Table S6).

Figure 8. Geographical distribution of the Strigamia crassipes species complex and candidate species within the study area, based on direct examination of specimens and critically revised published records.