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| Notiorhinus Moritz & Parra-Gómez, 2023 |
Abstract
The millipede family Siphonorhinidae (order Siphonophorida) shows a scattered distribution in South Africa, Madagascar, India, Southeast Asia, and North America. So far, the family is unknown from South America, while species of Siphonophoridae, the second family of the order, are relatively abundant on the continent. However, not a single Siphonophorida is known from Chile. Here we describe the monotypic genus Notorhinus gen. nov. with N. floresi sp. nov. and record a second Notorhinus (undescribed) species, as first records of the order Siphonophorida in Chile and of the family Siphonorhinidae in South America. Notorhinus gen. nov. is distinct from the remaining Siphonorhinidae by the arrangement of the sensilla basiconica on the antennae and other somatic and sexual characters. However, it shows close morphological affinities to the North American genus Illacme Cook and Loomis 1928. In the Americas Siphonorhinidae were previously only known from California (USA), where they inhabit subterranean micro-habitats. The Chilean species was found under a piece of decaying wood in a small patch of fragmented native forest. Thus, the group shows a disjunct antitropical distribution in America at ca. 37° North and 38° South. They might be the relict of a once greater distribution, which persisted in these areas due to similar climatic conditions.
Keywords: antitropical, Biobio, endemic, millipede, new genus, new species
Class Diplopoda de Blainville in Gervais, 1844
Subclass Chilognatha Latreille, 1802/1803
Infraclass Helminthomorpha Pocock, 1887
Subterclass Colobognatha Brandt, 1834
Order Siphonophorida Newport, 1844
Family Siphonorhinidae Cook, 1895
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| Notorhinus floresi sp. nov., photographs. A, B Living specimen in its natural habitat. Photographs by Edgardo Flores. C Male paratype (ZFMK-MYR 12267), habitus, lateral view. D Female paratype (ZFMK-MYR 12269), head, lateral view. |
Genus Notorhinus gen. nov.
Diagnosis: Pale, thin and elongated Siphonorhinidae with pyriform heads. In Notorhinus gen. nov. (Figs 2, 7) two backwards projecting spines are situated behind the elevated ozopores (Figs 4E, 8G), and the posterior margin of the metazonite (limbus) carries sculptures in shape of a fluke (tail-fin) (Figs 4D, 8H). Notorhinus gen. nov. differs from all other Siphonorhinidae genera by the absence of sensilla basiconica on antennomere 5 and the arrangement of numerous sensilla basiconica on antennomere 6 in a field not sunken into a sensory pit (Figs 3E, 8C). In Siphonorhinus and Kleruchus (see Attems 1930 for S. pellita; Attems 1938 for Teratognathus (syn. of Siphonorhinus) and Kleruchus) numerous sensilla basiconica are located in sensory pits (Sinnesgruben sensu Attems 1930) on antennomeres 5 and 6. In Illacme few sensilla basiconica are arranged in rows along the apical margin of antennomeres 5 and 6 (Marek et al. 2012, 2016) and in Madagascarhinus sensilla basiconica are arranged in 2 – 3 rows on antennomeres 5 and 6 (Wesener 2023). In Nematozonium no sensory structures are evident on the antennae according to Shelley and Hoffman (2004). Notorhinus gen. nov. differs from Illacme by the fusion of the first legs’ coxae to the sternite (Fig. 3G), forming a coxosternite (see Marek et al. 2012, 2016 for Illacme), as is the case in Siphonorhinus (see Enghoff et al. 2015). Furthermore, the specimens differ from Kleruchus by the presence of an anal scale/hypoproct (Figs 4F, 8I) (Analschuppe sensu Attems 1938).
Etymology: Noto is derived from the ancient greek νότος (nótos) meaning south and refers to the distribution of the genus in South America and the fact that it is the most southern record of the family Siphonorhinidae. Rhinus is derived from the ancient Greek ῥῑ́ς (rhī́s; genitive: ῥῑνός (rhīnós)), meaning nose, and refers to the acuminate head shape. Rhinus is often part of taxonomic names in the group (e.g. Siphonorhinidae Cook, 1895, Siphonorhinus Pocock, 1894, Madagascarhinus Wesener, 2023).
Notorhinus floresi sp. nov.
Diagnosis: Small (< 13 mm) elongated Siphonorhinidae with arched metazonites. Body pale, covered by setae, creating a velvety appearance (Fig. 2A). Anterior and posterior gonopods with 7 podomeres (Fig. 5E). Posterior gonopod apically with 3 branches, 2 laminate and 1 spinous (Fig. 5F). Pseudopenis prominent, cone-shaped (Fig. 5B). Posterior margin of metazonite (limbus) with small fluke-shaped sculpture (Fig. 4D). Antennomere 7 with spiniform sensilla basiconica in 2 rows (Fig. 3F) (1 row in Notorhinus sp.). Metazonite posterior margin straight (Fig. 4A) (sinuate in Notorhinus sp.). Differs from Notorhinus sp. (MNHNC 8390) in coloration, number of body-rings and its length relative to the number of body-rings (Fig. 2A): Notorhinus sp. has 80 body-rings but is only 11.5 mm long, while Notorhinus floresi sp. nov. has up to 54 body-rings, but a length of up to 13.8 mm.
Etymology: The species epithet floresi refers to Edgardo Flores, who collected the examined specimens, and honors his continuous engagement in nature conservation and his persistence on the protection of Nahuelbuta National Park and adjacent areas. Noun in genitive.
Leif Moritz and Antonio Parra-Gómez. 2023. Notorhinus floresi sp. nov. gen. nov.: The First Records of Siphonophorida in Chile and Siphonorhinidae in South America (Colobognatha). Arthropod Systematics & Phylogeny. 81: 565-579. DOI: 10.3897/asp.81.e100520
Notiorhinus nom. nov.
Leif Moritz and Antonio Parra-Gómez. 2023. Notorhinus Moritz & Parra-Gómez, 2023 (Siphonophorida: Siphonorhinidae) junior homonym of Notorhinus Roth, 1903 (Mammalia: †Astrapotheria: incertae sedis): proposed substitution by Notiorhinus nom. nov. Zootaxa. 5336(1); 149-150. DOI: https://doi.org/10.11646/zootaxa.5336.1.10