Stenotaenia linearis, (KOCH, 1835)

Bonato, Lucio & Minelli, Alessandro, 2008, Stenotaenia Koch, 1847: a hitherto unrecognized lineage of western Palaearctic centipedes with unusual diversity in body size and segment number (Chilopoda: Geophilidae), Zoological Journal of the Linnean Society 153 (2), pp. 253-286 : 267-269

STENOTAENIA LINEARIS ( KOCH, 1835)

Geophilus linearis Koch, 1835 : table 1 (original description). Latzel, 1880: 169 (in key), 189 (redescription). Folkmanova, 1952: 182 (in key), 188 (redescription), fig. 9. Lewis & Keay, 1994: 43 (redescription), figs 1–20. Stenotaenia linearis: Koch, 1847: 188 ; 1863: 120 (redescription), fig. 108. Clinopodes linearis: Attems, 1929a: 203 (in key), 205 (redescription); 1947: 120 (in key). Brolemann, 1930: 55 (in key), 143 (redescription), figs 201–207. Eason, 1964: 44 (in key), 107 (redescription), figs 147–152. Matic, 1972: 75 (in key), 93 (redescription), fig. 37. Kaczmarek, 1979: 62 (redescription and in key), figs 31 and 61.

Geophilus simplex Gervais, 1835: 9 (original description); 1937: 52 (in key). Newport, 1845: 435 (redescription); 1856: 88 (redescription). Berlese, 1903: (4) 10 (redescription). Synonymy by Gervais (1837: 52).

Geophilus brevicornis Koch, 1837 : table 3 (original description). Gervais, 1847: 319 (redescription). Synonymy by Koch (1847: 188).

Scnipaeus foveolatus Bergsøe & Meinert, 1866: 96 (original description). Geophilus foveolatus: Meinert, 1870: 66 (redescription). Synonymy by Latzel (1880: 189).

Himantarium caldarium Meinert, 1886: 148 (original description). Attems (1929a): 55. Syn. nov.

Geophilus linearis var. polyporus Verhoeff, 1896: 86 (original description). Syn. nov.

Geophilus ormanyensis Attems, 1903: 230 (original description). Nesogeophilus ormanyensis: Attems, 1929a: 184 (in key), 187 (redescription); 1947: 117 (in key). Matic (1972): 100 (redescription). Syn. nov.

Insigniporus acuneli Căpuşe, 1968: 700 (original description), fig. 1. Matic, 1972: 122 (redescription; misspelled as Insigniporus acunaeli ), fig. 48. Syn. nov.

Type locality: ‘ Regensburg’ = Regensburg ( Germany) .

Type material: Holotype, possibly male; apparently there are no more specimens in existence, as no specimen recognizable as such was found by one of the authors ( AM) in the main repository of Koch’s centipedes, in the collections of the Natural History Museum, London , or in the collections of the Museum für Naturkunde , Berlin, where other materials from Koch’s collection are preserved ( Moritz & Fischer, 1979).

Diagnosis: A Stenotaenia species of large body size (total length reaching 5 cm); c. 63–81 leg-bearing segments; labrum either with or without a single tubercle; first maxillae with distinct lappets on both the coxosternum and the telopodites; chitin lines of the forcipular coxosternum reaching the anterior condyles; anterior margin of the forcipular coxosternum angulated; forcipular intermediate articles distinct; sternal pore areas in the anterior part of the trunk oval, longer than wide, and placed on the posterior half of each sternum; each coxopleuron with one anterior and one posterior pouch with pores (see also Table 3).

Taxonomic history: Most authors have referred this species either to Geophilus or to Clinopodes , whereas its treatment under Stenotaenia has been very limited ( Koch, 1847, 1863; Fanzago, 1881a). Authors’ opinions also differ in the circumscription of this species and the possible recognition of subspecies within it.

Assignment to Stenotaenia: It is the type species of the genus, by subsequent designation by Pocock (1890).

Validity: This is a well-known species, even though its taxonomic circumscription is currently uncertain, in particular with respect to similar species such as S. naxia , S. giljarovi , S. palaestina , and S. asiaeminoris ( Table 3).

Remarks on synonyms

Geophilus simplex Gervais, 1835 . Geophilus simplex was described by Gervais (1835) from near Paris, but its original description was so incomplete that the use of this name was very limited. Gervais (1837, 1847) recognized that his G. simplex was identical to G. linearis Koch, 1835 , and most other authors followed this view (e.g. Berlese, 1903; Bagnall, 1918). We accept this synonymy, as the original descriptions of the two species are fully overlapping and no evidence suggests we should reject this view. As for the priority between these two names, both were published in the same year, but the actual dates are unknown to us. Gervais (1837, 1847) deliberately adopted his name G. simplex as valid, based on his opinion that Koch’s name had been published subsequently. He was followed by other authors ( Newport, 1845, 1856; Berlese, 1903; Bagnall, 1918), even though Berlese obviously misinterpreted the species. Conversely, most other authors in the 20th century used G. linearis as the valid name, in tens of works dealing with faunistics, taxonomy, ecology, physiology, and anatomy, whereas G. simplex has never been used as valid after 1918. Therefore, for the purpose of stability, we propose to consider G. linearis as the valid name for this species. If G. linearis is the senior synonym, it should be considered as the valid name following the principle of priority. Conversely, if it is the junior synonym, the conditions for the reversal of precedence (ICZN: art. 23.9) are not met, because G. simplex has been used as valid even after 1899 (e.g. see Koch, 1927; Attems, 1929a). Therefore, the matter has been referred to the International Commission of Zoological Nomenclature for a ruling under the plenary power ( Bonato & Minelli, 2007).

Geophilus brevicornis Koch, 1837 . Geophilus brevicornis was described by Koch (1837) from Germany, probably near Regensburg. It was later recognized as a junior synonym of G. linearis by the same author ( Koch, 1847), and has never been used as valid since then. In particular, Koch (1847) recognized that he had described G. linearis and G. brevicornis from a male and a female, respectively, of the same species. Indeed, the original descriptions and illustrations of the two nominal species are largely congruent, but for minor details in body colour and number of leg pairs, 75 and 79, respectively. Wood (1862) described a distinct species from North America under the same name G. brevicornis , which was therefore a junior homonym of Geophilus brevicornis Koch, 1837 . Wood’s species is obviously unrelated to Stenotaenia , but its identity remains uncertain and no substitute name for it has been proposed so far.

Scnipaeus foveolatus Bergsøe & Meinert, 1866 . Scnipaeus foveolatus was described by Bergsøe & Meinert (1866) from some specimens collected in the Botanic Garden of Copenhagen, and was redescribed by Meinert (1870) as G. foveolatus from other specimens from different localities. It was recognized as a junior synonym of G. linearis by Latzel (1880) and was not used as valid after that. On the basis of the original description and the secondary account by Meinert (1870), we confirm that S. foveolatus is identical to G. linearis , even in some traits that are diagnostic at the species level, including body size and number of trunk segments.

Himantarium caldarium Meinert, 1886 . Himantarium caldarium was described by Meinert (1886) from four specimens of both sexes collected in the Botanical Garden of Copenhagen. As the original description was very inadequate no further specimens were ever referred to H. caldarium , and the identity and taxonomic position of this nominal species has remained unresolved ( Attems, 1903, 1929a). Based on direct examination of the syntypes (preserved in the Zoological Museum, University of Copenhagen, without catalogue number), we found that H. caldarium is identical to S. linearis , as all the syntypes of the former fully agree with the latter species, particularly in the features of the clypeus, the labrum, the maxillae and the forcipular segment, the shape of the sternal pore areas and its variation along the trunk, the number of trunk segments, and the features of the last leg-bearing segment. Therefore, we consider H. caldarium as a junior synonym of S. linearis . The original description of H. caldarium was inaccurate in the following points: the sternal pore areas of the anterior part of the trunk were described as rounded, but they are actually oval; coxal pores were described as opening independently, at least in the female, but actually all of them open in two common pouches in all syntypes; the claws of the legs of the last pair were described as sexually dimorphic in size, but they are actually similar in both sexes. It is worth noting that S. linearis is known to occur frequently in hothouses and other suitable anthropic habitats in northern Europe (e.g. Barber & Keay, 1988). In particular, the presence of this species in the Botanical Garden of Copenhagen in the second half of the 19th century is documented by the fact that some specimens collected there had been described previously by Bergsøe & Meinert (1866) as Scnipaeus foveolatus (see above). The presence of S. linearis in Copenhagen has been documented even more recently ( Enghoff, 1973).

Geophilus linearis var. polyporus Verhoeff, 1896 . Geophilus linearis var. polyporus was described by Verhoeff (1896) from an unknown number of specimens from the Rhineland in Germany. Based on the very poor diagnosis, it should differ from typical G. linearis only in having 30 or more coxal pores on each side, whereas the typical number for G. linearis was given as nine or ten. This nominal taxon was completely ignored in subsequent literature. We were not able to examine the type material, which is apparently neither preserved in Verhoeff’s collections at the Museum für Naturkunde in Berlin ( Moritz & Fischer, 1979) nor at the Zoologische Staatssammlung München (J. Spelda and M. Unsöld, pers. comm.). Extensive faunistic investigations in that region failed to secure other specimens referable to this taxon, instead they documented that the populations of Stenotaenia from that region may be obviously referred to the typical S. linearis . Furthermore, by considering that no other geophilid species closely resembling S. linearis actually lives in that region, we can accept Verhoeff’s identification of the specimens as belonging to S. linearis , but we consider that their taxonomic distinction was unwarranted. Therefore, we consider G. linearis var. polyporus as a junior synonym of G. linearis . In any case, Geophilus linearis var. polyporus Verhoeff, 1896 is an invalid name, as it is a primary junior homonym of Geophilus polyporus Haase, 1887 , a species from the D’Urville island off New Zealand, which is still of uncertain taxonomic position but is clearly unrelated to Stenotaenia .

Geophilus ormanyensis Attems, 1903 . Geophilus ormanyensis was described by Attems (1903) from two specimens from a locality near Klausenburg, in Romania, but the identity of this nominal species remained unclear, and no other specimen has been referred to it. As the large difference in the number of leg pairs between the two syntypes (55 in a male, 73 in a female) is unusual within a single geophilomorph population, it is highly probable that they are not conspecific. Therefore, in order to fix the identity of G. ormanyensis unambiguously, we designate the female syntype as the lectotype of this species; the lectotype is preserved in the Naturhistorisches Museum in Wien, catalogue number NHMW4813 (V. Stagl, pers. comm.). Based on the original account, the lectotype may be confidently regarded as belonging to S. linearis , which is known to occur in the region, whereas it differs from other species of Stenotaenia known from the same region at least in the number of trunk segments. Therefore, we regard G. ormanyensis as a junior synonym of G. linearis . Instead, the male with 55 leg-bearing segments is probably closer to other nominal species, such as S. antecribellata or S. cribelliger .

Insigniporus acuneli Căpuşe, 1968 . Insigniporus acuneli was described by Căpuşe (1968) from a single male from the Banat region in Romania. No other specimen has been referred to this nominal species, the status of which and validity have remained unassessed ( Matic, 1972). Based on the detailed description and illustrations available ( Căpuşe, 1968; Matic, 1972), and considering the current knowledge of the centipede fauna of Romania, I. acuneli can be confidently recognized as a synonym of S. linearis . Insigniporus acuneli agrees with S. linearis in the general body shape and size, and in all diagnostic characters, including the shape of the cephalic shield and antennae, the sculpture and pattern of setae in the clypeus, the shape of the labrum, the hairiness and shape of the maxillae, the overall features of the forcipular segment, the number of trunk segments, the shape of the sternal pore areas and their variation along the trunk, the pattern of the coxal pores, the shape and other features of the legs of the last pair. The only apparent difference between the two nominal species is in the shape of the sternum of the last leg-bearing segment, which was illustrated as subtrapezoid in I. acuneli , whereas in S. linearis it usually appears subrectangular, only slightly narrowing backwards; however, this disagreement is perhaps explained by interindividual variation or by the incorrect interpretation of the microscopical evidence. It is worth noting that S. linearis is already known to occur in that region ( Matic, 1972).

Distribution: Different authors have recorded S. linearis from throughout the entire range of Stenotaenia , as reconstructed here, often because they misidentified specimens belonging to other congeneric species. Based on the critical evaluation of the published accounts, as well as on the direct examination of representative specimens from different regions, we found that populations reliably referred to S. linearis occur mainly in Central Europe, westward to Great Britain and central France, northward to the Baltic region, including Denmark and southern Scandinavia, eastward to Latvia, the Carpathian chain, and the western coast of the Black Sea, and southward to the Alps, including the Maritime Alps, and Transylvania ( Fig. 2 ). Published records from other regions need to be reassessed, with respect to other species of Stenotaenia occurring there, as for the southern part of France, most of the remaining Balkan Peninsula, the Aegean islands, and the entire region of Anatolia.

Figures

Figure 2. Geographical distribution of Stenotaenia species. The previously published and new records have been plotted upon a grid of 30′ latitude ¥ 30′ longitude. The type localities of all nominal taxa are indicated by circles (full circles for valid species, empty circles for synonyms), with the following abbreviations: ab, abbreviatus; ac, acuneli; al, albanensis; an, antecribellatus; as, asiaeminoris; bo, bosporanus; br, brevicornis; c, caldarium; cr, cribelliger; fi, fimbriatus; ff, forficularius; fv, foveolatus; fr, frenum; gi, giljarovi; gr, graecus; li, linearis; na, naxius; or, ormanyensis; pl, palaestinus; po, polyporus; pp, palpiger; rh, rhodopensis; ro, romanus; sl, silvestrii; sm, simplex; so, sorrentinus; st, sturanyi.