Derkarabetian, Shahan, Starrett, James, Tsurusaki, Nobuo, Ubick, Darrell, Castillo, Stephanie & Hedin, Marshal, 2018, A stable phylogenomic classification of Travunioidea (Arachnida, Opiliones, Laniatores) based on sequence capture of ultraconserved elements, ZooKeys 760, pp. 1-36: 1

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Family PARANONYCHIDAE Briggs, 1971 

Type genus.

Paranonychus  Briggs, 1971

Type species.

Paranonychus brunneus  (Banks, 1893).


The Paranonychidae  can be diagnosed by their relatively complex glans (except Paranonychus  ) (Figure 7 and Suppl. material 2: Figure 4), and by their intestinal complex (Suppl. material 2: Figure 2). For all taxa that have been examined, the paranonychids possess a small D1 that is circular to subtriangular, and a simple and shorter OD3. The paranonychids are restricted to western North America and East Asia. In southern Japan the paranonychids are sympatric with Yuria  and can be diagnosed by several characteristics: Yuria  possesses a free ninth tergite, and the penis has a dorsal plate with fused stylus; the paranonychids do not have a free ninth tergite and the penis glans lacks a dorsal plate. In western North America, the paranonychids are sympatric and syntopic in surface habitats with the Cladonychiidae  ( Briggsus  , Isolachus  ) and Cryptomastridae  ( Cryptomaster  ). The paranonychids can be differentiated from these families by the structure of D1: paranonychids possess a small circular to subtriangular unbranched D1, while Cladonychiidae  and Cryptomastridae  possess an elongate, triangular, and branched D1.

Included genera and species.

Paranonychus  (Figure 1K). This trans-Beringian genus includes three known species: P. brunneus  (Banks, 1893) distributed in the Coast and Cascade Ranges of Oregon and Washington with records extending north to Alaska; P. concolor  Briggs, 1971, recorded from a single location in the southern Cascade Range of Oregon; and P. fuscus  found throughout northern Honshu in Japan.

Metanonychus  Briggs, 1971. This genus and all species were described by Briggs (1971) and are restricted to the moist forests of the Pacific Northwest of North America. Metanonychus  includes three species: M. nigricans  Briggs, 1971 with two subspecies, M. n. nigricans  and M. n. oregonus  , found in Oregon; M. setulus  Briggs, 1971 with five subspecies, M. s. setulus  , M. s. cascadus  , M. s. mazamus  , M. s. navarrus  , and M. s. obrieni  , found in Oregon, Washington, and northern California; and M. idahoensis  Briggs, 1971 found in northern Idaho.

Sclerobunus  Banks, 1893 (Figure 1L). Recently revised by Derkarabetian and Hedin (2014), Sclerobunus  is distributed throughout western North America and currently includes 12 species divided into three species groups. The nondimorphicus group includes S. nondimorphicus  Briggs, 1971 from Oregon, Washington, and British Columbia, and S. idahoensis  Briggs, 1971 from northern Idaho. The cave-obligate cavicolens group includes: Sclerobunus cavicolens  (Banks, 1905) restricted to Lewis and Clark Caverns, Montana; Sclerobunus ungulatus  (Briggs, 1971) from caves in Great Basin National Park, Nevada; Sclerobunus madhousensis  (Briggs, 1971) from caves near Provo, Utah. The robustus group includes the widespread S. robustus  (Packard, 1877), S. glorietus  Briggs, 1971, and S. skywalkeri  Derkarabetian & Hedin, 2014, all distributed throughout the high elevation forests of the southwestern United States, and S. jemez  Derkarabetian & Hedin, 2014, S. klomax  Derkarabetian & Hedin, 2014, S. speoventus  Derkarabetian & Hedin, 2014, and S. steinmanni  Derkarabetian & Hedin, 2014, which are all troglomorphic species restricted to cave and talus habitats along the eastern edge of the southern Rocky Mountains in New Mexico and Colorado.

Kaolinonychus  Suzuki, 1975. This monotypic genus endemic to South Korea is recorded mostly from caves. Kaolinonychus coreanus  (Suzuki, 1966) includes two subspecies K. c. coreanus  and K. c. longipes  .

Metanippononychus  Suzuki, 1975. (Figure 1M). Endemic to Japan, Metanippononychus  is restricted to southern Honshu, Shikoku, and Kyushu and includes four species: M. daisenensis  Suzuki, 1975; M. iriei  Suzuki, 1975, with two subspecies M. i. iriei  and M. i. yakuensis  ; M. iyanus  Suzuki, 1975; M. tomishimai  Suzuki, 1975, with two subspecies M. t. tomishimai  and M. t. awanus  .

Nippononychus  Suzuki, 1975. A monotypic genus endemic to Japan, Nippononychus japonicus  (Miyosi, 1957) is restricted to southern Honshu and Shikoku.

Zuma  (Figure 1N). Zuma  includes two species restricted to forests of central and northern California: Zuma acuta  Goodnight & Goodnight, 1942 restricted to the coastal forests south of San Francisco; Zuma tioga  Briggs, 1971 found in the central and northern Sierra Nevada range.

Izunonychus  Suzuki, 1975. A monotypic genus endemic to Japan, Izunonychus ohruii  Suzuki, 1975 is restricted to the Izu peninsula and Hakone area in central Honshu.

Kainonychus  Suzuki, 1975 (Figure 1O). A monotypic genus endemic to Japan, Kainonychus akamai  (Suzuki, 1972) includes two subspecies, K. a. akamai  distributed throughout northern Honshu and K. a. esoensis  restricted to Hokkaido.


In this study all genera in the Paranonychidae  have been sampled and the generic relationships are consistent and highly supported across all analyses (Figs 4, 5). Although the study of Derkarabetian et al. (2010) only included North American taxa, the relationships of paranonychids recovered here are the same, notably Paranonychus  as the earliest diverging genus, and a sister relationship between Sclerobunus  and Metanonychus  . The familial name Sclerobunidae  has been used previously ( Giribet et al. 2010) for the "northern triaenonychids". However, Paranonychidae  and the subfamily Paranonychinae  Briggs, 1971 have priority over the names Sclerobunidae  and Sclerobuninae  Dumitrescu 1976.

The Japanese genera Metanippononychus  and Nippononychus  show levels of UCE divergence consistent with congeners (Figs 4, 5). Intermediate morphological forms between Nippononychus japonicus  and Metanippononychus daisenensis  can be found where the two species come into contact (Tsurusaki pers. obs.). These genera are differentiated only by tarsal claw structure: Metanippononychus  possessing a ventral tooth on the median prong of the hind claws. The original drawings of male genitalia show that M. daisenensis  and N. japonicus  differ in the width of the stylus ( Suzuki 1975b). However, the penis of N. japonicus  is highly similar to that of the geographically proximate M. tomishimai tomishimai  .

Kury et al. (2014) includes Paranonychus fuscus  (formerly Mutsunonychus fuscus  ) as a synonym of Paranonychus brunneus  (Banks, 1893) based on Shear’s (1986) statement " Paranonychus brunneus  (= Mutsunonychus fuscus  Suzuki; Paranonychidae  )". Later in Shear and Derkarabetian (2008), the genus Mutsunonychus  was formally synonymized under Paranonychus  , and although a potential species level synonymy was noted, it was not formally established. The levels of UCE divergence between P. brunneus  and P. fuscus  are consistent with species level divergences compared to other pairs of congeneric taxa included (Figs 4 and 5), and as such, P. fuscus  is again treated as a distinct species here.