﻿New subgenera and a new species of the genus Raphignathus Dugès (Prostigmata, Raphignathidae), with taxonomic notes on the genus Neoraphignathus Smiley & Moser

﻿Abstract Four new subgenera in the genus Raphignathus Dugès are hereby proposed: Raphignathus (Raphignathus), subgen. nov., Raphignathus (Monoraphignathus), subgen. nov., Raphignathus (Diraphignathus), subgen. nov., and Raphignathus (Triraphignathus), subgen. nov. These subgenera are diagnosed by the number of setae on the interscutal membrane of females. A new species, R. (D.) neohecmatanaensissp. nov., is described and illustrated based on females collected from Ziziphusspina-christi Mill. (Rhamnaceae). The taxonomic status of the monotypic genus Neoraphignathus Smiley & Moser and three species (R.evidus, R.hsiufui, and R.johnstoni) are discussed. A key to world species of the family Raphignathidae is given.


Introduction
Members of the family Raphignathidae Kramer (Prostigmata, Raphignathoidea) are active predators feeding on small arthropods (Meyer and Ueckermann 1989).They are mostly found in humus soil under dense bushes, leaf litter, lichens, and mosses and on a wide range of plants (Fan and Zhang 2005).Raphignathids have cervical peritremes and contiguous coxae and are divided into two genera: Raphignathus Dugès (76 species) and Neoraphignathus Smiley & Moser (one species, N. howei Smiley & Moser) (Smiley and Moser 1968;Khanjani et al. 2013).These genera are mainly differentiated by the presence and absence of dorsal shields, respectively.Raphignathus species have a worldwide distribution, whereas Neoraphignathus is only known from Louisiana, USA (Beron 2020).
The genus Raphignathus (type species: R. ruberrimus Dugés) was diagnosed as having three, or sometimes four, dorsal shields (Atyeo et al. 1961).While discussing the chaetotaxy of the superfamily Raphignathoidea, Atyeo et al. (1963) provided a general description of the genus Raphignathus.They considered the number of setae on prodorsal shields and on interscutal membrane as important taxonomic characteristics.In addition, the number of setae on the interscutal membrane was also used to differentiate among the species in recently published diagnostic keys (Nasrollahi et al. 2018;Pishehvar andKhanjani ZooKeys 1176: 165-180 (2023), DOI: 10.3897/zookeys.1176.106224 Eid Muhammad Khan et al.: New subgenera and a new species of Raphignathus 2021).The validity of some Raphignathus species has been questionable due to ontogenetic development, and more females need to be collected and observed (Dönel and Doğan 2011).Raphignathus broomicus Podder was considered a species inquirenda due to uncertain and doubtful characters (Doğan and Erman 2019).Until now, most of published work on the family Raphignathidae has been regional and includes identification keys for China, India, Iran, and Turkey (Fan and Yin 2000;Doğan and Erman 2019;Pishehvar and Khanjani 2021).
In the present study, four new subgenera of Raphignathus are erected based on the prominent and consistent morphological character (number of setae on interscutal membrane).A new species, R. (D.) neohecmatanaensis sp.nov. is described and illustrated based on females.Some taxonomic notes on the monotypic genus, Neoraphignathus Smiley & Moser, and the identity of three species (R. evidus, R. hsiufui, and R. johnstoni) are concisely discussed.A diagnostic key to the world species is also provided.

Material and method
All published taxonomic literature on the family Raphignathidae was critically reviewed to confirm the validity of the species, subgeneric divisions and to prepare a diagnostic key of world species.The new raphignathoid species was collected by shaking foliage of Ziziphus spina-christi Mill.(Rhamnaceae) over a white sheet of paper; mite specimens were preserved in small vials containing 70% ethanol.The specimens were permanently mounted on glass slides in Hoyer's medium and identified under a phase-contrast microscope (BX51, Olympus, Tokyo, Japan).All measurements of the holotype specimen are given in micrometers (μm), followed by those of paratypes in the parenthesis.The terminology and abbreviations used in the description of the new species follow those of Kethley (1990) and Grandjean (1939Grandjean ( , 1944Grandjean ( , 1946)).The holotypes and paratypes were deposited at the King Saud Museum of Arthropods (KSMA, Acarology section), Department of Plant Protection, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia.

Results
Four new subgenera of the genus Raphignathus are proposed: Raphignathus (Raphignathus), subgen.nov., Raphignathus (Monoraphignathus), subgen.nov., Raphignathus (Diraphignathus), subgen.nov., and Raphignathus (Triraphignathus), subgen.nov., on the basis of the number of setae on the interscutal membrane, a prominent and consistent morphological character.A new species, R. (D.).neohecmatanaensis sp.nov., is described and illustrated based on adult females.Furthermore, taxonomic notes on the status of the monotypic genus, Neoraphignathus Smiley & Moser, and the identity of three species (R. evidus, R. hsiufui and R. johnstoni) are discussed.A diagnostic key to the world species is also presented.

Taxonomic divisions of the genus Raphignathus
The presence or absence of prodorsal shields are diagnostic for the differentiation of the two existing raphignathid genera.Atyeo (1963) discussed in detail the chaetotaxy of the superfamily Raphignathoidea while describing seven Raphignathus species.This author also provided comprehensive diagnosis of Raphignathus and stated that the number of setae on the shields and the interscutal membrane is a consistent and important diagnostic character.The number of setae on the interscutal membrane is considered to be a strong character and has been used in identification keys to distinguish species (Nasrollahi et al. 2018;Pishehvar and Khanjani 2021).Through our extensive study of the literature of all 76 Raphignathus species, we find that the number of setae on the interscutal membrane can be used to erect subgenera.

Notes on the taxonomic status of the genus Neoraphignathus
To date, the family Raphignathidae has included two genera, Raphignathus and Neoraphignathus, which have been differentiated based on the presence or absence of shields on the dorsum.The monotypic genus, Neoraphignathus (type species: N. howei Smiley & Moser) was erected in 1968, based on a single female holotype specimen without detailed description and illustration.Based on observations and the collection of the immature specimens of the genus Raphignathus, prodorsal shields are weakly developed or absent in immatures.Atyeo et al. (1961) has reported that dorsal shields are sometime feebly developed.Since its first description, the type species, N. howei, has not been redescribed, nor have new Neoraphignathus species been described.We suggest that the type specimen of N. howei be re-examined and also that more specimens be collected from the type locality to confirm the absence of a dorsal shield to confirm the validity of Neoraphignathus.

Notes on the validity of Raphignathus evidus, R. hsiufui, and R. johnstoni
The taxonomic identity of Raphignathus evidus Fan, R. hsiufui Fan, and R. johnstoni Womersley are doubtful.These species were originally described based on single specimens, minor differential characteristics (i.e.number of dorsal setae on the lateral prodorsal shield; all three species have two pairs of setae on lateral shields), and small opisthosomal shields.In contrast, all other Raphignathus species have three pairs of setae on the lateral prodorsal shields along with the pores (ia).The immature stages of Raphignathus gradually develop the prodorsal shields, striation patterns, and leg setae (Fan and Yin 2000).For instance, the immature stages of R. giselae, R. lenis, and R. caspicus each have two setae on the lateral prodorsal shields (three setae in adult) and small lateral prodorsal shields with weakly developed striations.Moreover, we also observed the immatures from more than 10 populations of Raphignathus and found reduced size of weakly sclerotized lateral prodorsal shields and setae set on the edges of shields.Based on this evidence, R. evidus, R. hsiufui, and R. johnstoni should be revised and more specimens collected to confirm their validity.
Etymology.The specific epithet is in reference to the similarity of the new species to R. (D.) hecmatanaensis; neo = new.
Remarks.Raphignathus (D.) neohecmatanaensis sp.nov., belongs to the subgenus Diraphignathus subgen.nov.The new species resembles to R. (D.) hecmatanaensis Khanjani & Ueckermann in having two pairs of setae (d1 and e1) on the interscutal membrane, two setae on the palp femora, and two small plates present posterolateral to the median prodorsal shield.However, the new species differs from R. (D.) hecmatanaensis in the absence of an endopodal shield (vs present), femur IV with two setae (vs three), and leg tarsus I with one solenidion (vs two solenidia).

Key to genera, subgenera, and all known species of the family Raphignathidae
Five species are not included in the key.Raphignathus longimanus (Koch), R. impressus (Koch), R. hispidus (Dugès), and R. deserticula (Trägårdh)   sidering the morphologically valid, persistent, and prominent characters (Atyeo 1963).The use of subgenera supports the identification of raphignathoid species and will help to avoid designation of new species based on variable characters.Raphignathus evidus, R. hsiufui, and R. johnstoni are considered doubtfully valid.They were described based on size of lateral prodorsal shields and number of setae, but these in these characteristics they resemble immature stages (Fan and Yin 2000).The monotypic genus Neoraphignathus was erected based on only the single type specimen with a restricted geographical region and its description is brief.We suspect it might have been described based on the immature stage of a Raphignathus species, and we suggest that the type species be revised and more specimens collected to confirm the validity of the species and genus.

(Raphignathus), subgen. nov.
Interscutal membrane with two pairs of setae.Etymology.The sub-generic epithet refers to the two pairs of setae on interscutal membrane.The species included in this new subgenus are widely distributed over the world.