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| Illacme socal Marek & Shear, in Marek, Hall, Lee, Bailey, Berger, Kasson et Shear, 2023. |
Abstract
The millipede fauna inhabiting deep soil are poorly known. They are small and threadlike, slow moving, lacking pigmentation, and rarely encountered due to their obscure underground way of life. One family, the Siphonorhinidae, encompasses four genera and 12 species in a fragmentary distribution in California, southern Africa, Madagascar, the Malay Archipelago, and Indo-Burma. The family is represented in the Western Hemisphere by a single genus, Illacme Cook & Loomis, 1928 from California, with its closest known relative, Nematozonium filum Verhoeff, 1939, from southern Africa. A new species of this family is documented from soil microhabitats in the Los Angeles metropolitan area, Illacme socal Marek & Shear, sp. nov. Based on this discovery and the recent documentation of other endogean millipede species, we show that these grossly understudied subterranean fauna represent the next frontier of discovery. However, they are threatened by encroaching human settlement and habitat loss, and conservation of this species and other subterranean fauna is of high importance.
Key words: Colobognatha, Illacme plenipes, interstitial, Myriapoda, Siphonorhinus, super-elongation
Class Diplopoda de Blainville in Gervais, 1844
Subclass Chilognatha Latreille, 1802/1803
Infraclass Helminthomorpha Pocock, 1887
Subterclass Colobognatha Brandt, 1834
Order Siphonophorida Hoffman, 1980
Family Siphonorhinidae Cook, 1895
Genus Illacme Cook & Loomis, 1928
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| Habitat of Illacme socal sp. nov. Whiting Ranch Wilderness Park, Orange County, California A California live oak woodland habitat surrounded by chaparral shrubland B close up of oak woodland habitat C type locality beneath oak canopy D an I. socal sp. nov. individual (center) encountered beneath the humus layer and embedded within the underlying soil matrix. |
Illacme socal Marek & Shear, sp. nov.
Vernacular name: Los Angeles Thread Millipede
Diagnosis: Adult males of I. socal sp. nov. are distinct from I. plenipes and I. tobini based on the combination of: Metazonites slightly wider than prozonites, with faintly enlarged paranota (Suppl. material 5: fig. S17), not subequal in width as in I. plenipes nor noticeably wider as in I. tobini. Ozopore peritreme with two large backwards projecting spines (sp, Suppl. material 5: fig. S20) as in I. plenipes, not lacking two large spines as in I. tobini. Ozopore ringed with ca. 14 setae. Ozopores situated inside (mediad) lateral margin, oriented dorsally (Suppl. material 5: fig. S17) as in I. plenipes, not dorsolaterally and near lateral margin as in I. tobini. Metazonite posterior margin (limbus) lined with anchor-shaped, posteriorly projecting spines as in I. plenipes (an, Suppl. material 5: figs S17, S20); spines not quadrate-shaped as in I. tobini. Posterior margin of metazonite straight as in I. plenipes, not sinuate with anteriorly curved paramedial margins as in I. tobini (Suppl. material 5: fig. S17). Telson densely covered with ...
Etymology: The species name refers to its type locality in Southern California, commonly shortened to SoCal.
Paul E. Marek, Charity L. Hall, Cedric Lee, James Bailey, Matt C. Berger, Matt T. Kasson and William Shear. 2023. A New Species of Illacme from southern California (Siphonophorida, Siphonorhinidae). ZooKeys. 1167: 265-291. DOI: 10.3897/zookeys.1167.102537
new.nsf.gov/science-matters/researchers-uncover-new-millipede-species-under
