Tenebriochernes, Bedoya-Roqueme & Torres, 2019

Bedoya-Roqueme, Edwin & Torres, Richard A., 2019, Tenebriochernes, a new genus and species of Chernetidae (Arachnida: Pseudoscorpiones) from north-western Colombia, with ecological observations, Zootaxa 4624 (1), pp. 87-107 : 89-90

Tenebriochernes gen. nov.

urn:lsid:zoobank.org:act:A4181424-D1A0-4A5A-8025-1EFC040DF730

Type species: Tenebriochernes concavus n. sp.

Etymology. The generic name refers to the presence of the type species within caves (tenebrio, Latin, shunner of light, lover of darkness), which is combined with the genus name Chernes (Greek, labourer). It is masculine in gender.

Diagnosis: Tenebriochernes n. gen. can be distinguished from all other chernetid genera by the following combination of characters: presence of 7 denticulate and thickened setae (Sd) proximal of the base of fixed chelal finger; the concavity on the retrolateral margin of the pedipalpal patella; the chelal hand shape and the strong concavity on the base of the movable chelal finger proximal of the condyle; trichobothrium ib, ist, esb and eb grouped at the base of the fixed finger in a diagonal row, trichobothrium st equidistant between t and sb, proximal of nodus ramosus and approximately at the same level as est; females spermathecae with a distally expanded and less globose sacs with darkened tips, and two long tubes which not leading to a single medium chamber with a cribriform plate; tarsus IV without tactile seta.

Remarks: The genus Tenebriochernes is referred to the subfamily Chernetinae by lacking T-shaped spermathecae as occurs in the Lamprochernetinae and the angular posterior margin of the carapace, exclusive of the Goniochernetinae . Like a number of other chernetine genera, Tenebriochernes has four blades in the cheliceral rallum and lacks a tactile seta on tarsi III and IV. Tenebriochernes differs from the genera Atherochernes Beier, 1955 from Venezuela, Austrochernes Beier, 1932 and Balgachernes Harvey, 2018 from Australia ( Harvey 2018) and Eumechochernes Beier, 1932 from Hawaii ( With 1905; Beier 1932, 1954; Harvey 2013) by the pattern of trichobothrium ib, ist, esb and eb grouped at the base of the fixed finger in a diagonal row; trichobothrium st equidistant between t and sb, trichobothrium st almost at the same level as est; venom duct long, nodus ramosus midway between trichobothria t and st; the chelal hand shape and the strong concavity on the base of movable chelal finger proximal of the condyle, the robust pedipalps and the concavity on the retrolateral margin of the pedipalpal patella. It differs from the genus Marachernes Harvey, 1992 from Australia by the absence of an internolateral mound on the male movable chelal finger and the spermathecae with two long tubes and distally expanded sacs with darkened tips. It differs from the genera Mirochernes Beier, 1930 from United States and Semeiochernes Beier, 1932 from Costa Rica ( Beier 1930, 1932; Harvey 2013) by the robust and granulated pedipalps highly sexually dimorphic, the males possess greatly enlarged chelae and chelal peg-like processes, that are absent in females (Chrystophoryová et al. 2018), as well as the distribution of the trichobothria, with ist distal of est on the fixed chelal finger and st closer to t than to sb on the movable chelal finger. It differs from the genera Dinocheirus Chamberlin, 1929 from American region, Asia and Europe, that bears only five setae on the cheliceral hand (b and es being acuminate), tarsus with an acuminate tactile seta distal of midpoint, position of the trichobothrium ib at the same level of est, and trichobothrium isb proximal of it ( Chamberlin 1929; Hoff 1947; Muchmore 1974).

The morphology of the spermatheca of females has been found to provide reliable characters for the delimitation of genera in Chernetidae (e.g. Muchmore 1974, 1975; Muchmore & Hentschel 1982, Hentschel & Muchmore, 1989; Mahnert 1979, 1985; Harvey 1995; Harvey & Volschenk 2007). The spermathecae of Tenebriochernes have two long tubes, opening distally into expanded sacs with darkened tips, which distinguish it from the genera Chernes Menge, 1855 in the Holarctic region, Ceriochernes Beier, 1937 from Asia and South America, Cocinachernes Hentschel & Muchmore, 1989 from Mexico, Illinichernes Hoff, 1949 , Neochelanops Beier, 1964 , Semeiochernes Beier, 1932 ; Hesperochernes Chamberlin, 1924 from the American region; Maxchernes Feio, 1960 from South America; Austrochernes Beier, 1932 , Paraustrochernes Beier, 1966 , and Satrapanus Harvey and Volschenk, 2007 from Australia ( Beier 1932; 1937; 1966; Hoff 1949; Hentschel & Muchmore 1989; Muchmore 1999; Harvey & Volschenk 2007; Harvey 2013). Unfortunately, the spermathecae of many chernetine genera remain undescribed and others have yet to be studied in detail, which hinders our understanding of the group. In this sense, a further review of the spermathecal morphology is necessary for each of the genera of Chernetidae family, to clarify and establish phylogenetic relationships within this large and complex family (e.g. Harvey 1991, 1995, 2013; Muchmore 1974, 1975; Hentschel & Muchmore 1989).

Finally, Tenebriochernes resembles Neoallochernes Hoff, 1947 from the United States, Central America, and some Caribbean islands in having spermatheca with dark tips. The genus Neoallochernes is characterized by the spermathecae in form of elongated sacs with short slender tubules leading into a single median chamber with a cribriform plate; in this sense, the unusual spermathecal morphology is clearly diagnostic for this genus (e.g. Hoff 1957; Muchmore 1975, 1992, 1996). Tenebriochernes can be distinguished from Neoallochernes by the spermathecae with distally expanded and less globose sacs, and two long tubes which are not leading to a single medium chamber with a cribriform plate. Likewise, Tenebriochernes has the setae sbs on the cheliceral hand (absent in Neoallochernes ), four blades on the rallum (three blades in Neoallochernes ), and also differs by the concavity on the prolateral margin of the pedipalpal patella; further in the shape of the chelal hand: the strong concavity at the base of the movable chelal finger proximal of the condyle, and the distribution of trichobothria ib, ist, esb and eb which are grouped at the base of the fixed finger in a diagonal row. Due to these characters, the new genus can be distinguished from all other genera of the family Chernetidae by the shape of the spermathecae, the chelal hand shape with a strong concavity near the base of the movable finger, the form of the retrolateral accessory teeth of the movable chelal finger, proximal of fingertip of fixed chelal finger, the position of the trichobothria, and the concavity on the retrolateral margin of the pedipalpal patella.