The subfamily Thorictinae (Coleoptera, Dermestidae) from Saudi Arabia

Abstract In this study, the Saudi Arabian Thorictinae beetle species, Thorictus riyadhensis Háva & Abdel-Dayem, sp. nov., T. shadensis Háva & Abdel-Dayem, sp. nov., T. sharafi Háva & Abdel-Dayem, sp. nov., T. hanifahensis Háva & Abdel-Dayem, sp. nov. are described, illustrated, and compared with related species. Three other species: T. castaneus Germar, 1834; T. foreli Wasmann, 1894; and T. peyerimhoffi Chobaut, 1904 are excluded from the fauna of Saudi Arabia. A list of Thorictinae species from the Arabian Peninsula is provided.


Introduction
Thorictinae Agassiz, 1846, with 189 described species worldwide, is a myrmecophilous subfamily of the family Dermestidae (Coleoptera) (Háva 2020a(Háva , 2021. Its members can be recognized by their small size, strongly convex and strongly hardened bodies, reduced or absent eyes, absent wings, and their rounded hind coxae that do not reach the outer edge of the metasternum (Háva 2004;Leschen et al. 2010). Thorictinae are currently divided into two tribes, Thaumaphrastini and Thorictini, and include four genera: Thorictodes Reitter, 1875, Afrothorictus Andreae, 1967, Macrothorictus Andreae, 1967, and Thorictus Germar, 1834(Háva 2020a. The genus Thorictodes comprises only five species (Herrmann et al. 2011). Two species in Afrothorictus and seven species in Macrothorictus are known (Háva 2020a). The genus Thorictus currently includes 175 species and subspecies from the Palearctic, Oriental, and Afrotropical Regions (Háva 2015a(Háva , 2020a. Thorictinae fauna, in the Arabian Peninsula in general and in Saudi Arabia in particular, is poorly studied due to the lack of adequate dedicated investigation and scant published records for this group. So far, only four species are known from the Arabian Peninsula (Háva 2010(Háva , 2021Abdel-Dayem et al. 2017). Thorictus peyerimhoffi Chobaut, 1904 was the first species to be described from Saudi Arabia (Háva 2010) and is now excluded from the Saudi fauna due to misplacement of the type locality "Kasrer-Rabbat", to Saudi Arabia. The second species, T. arabicus, was described by Háva (2010) in the Eastern Province of Saudi Arabia. In their work on the beetle fauna of Rawdhat Khorim National Park, Central Saudi Arabia, Abdel-Dayem et al. (2017) reported Thorictodes heydeni Reitter, 1875, T. castaneus Germar, 1834, andT. foreli Wasmann 1894. However, T. castaneus and T. foreli are now excluded from the Saudi fauna due to misidentifications. Recently, Háva (2021) described Thorictus omanensis from Oman.
While examining myrmecophilous dermestid specimens from Saudi Arabia, four new species of Thorictus were determined and are described below. The present study follows the revision of Thorictinae from the Afrotropical Region (Háva 2013(Háva , 2014(Háva , 2015b(Háva , 2020b.

Measurements
The size of beetles' bodies or body parts can be useful in species recognition; thus, the following measurements were made. Total length (TL): linear distance from anterior margin of pronotum to apex of elytra, pronotal width. (PW): maximum linear transverse distance and elytral width. Elytral width (EW): maximum linear transverse distance. All measurements are given in millimeters. Locality labels are cited in the original version.
The ant species used in the present paper are identified by Dr Mostafa R. Sharaf (Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia) and the nomenclature follow the online catalogue (Bolton 2020 Remasrks. An endemic species to Saudi Arabia that was originally described from the Eastern Province (Háva 2010) (Fig. 1). The species was erroneously published by Abdel-Dayem et. al (2017) as T. castaneus Germar, 1834, a Mediterranean species that has been reported in Algeria, Egypt, Greece, Morocco, and Syria (Háva 2015a).   Description of holotype. Body small, brown covered by long, yellow setae on dorsal surfaces and short setae on ventral surfaces. Measurements (mm): TL 2.9, PW 1.9, EW 1.9. Head finely punctate with long yellow setae. Labial palpi entirely brown. Antennae brown, with 11 antennomeres; antennal club compact, with three antennomeres. Pronotum as finely punctate as head and covered by long yellow setation. Lateral margin of pronotum not dentate. Pronotum in posterior part near scutellum without bumps. Ventral posterior pronotal angles with long yellow setation. Scutellum not visible from above. Elytra very finely punctate covered by long yellow setation. Each elytron in anterior part near humeri with one large bump. Epipleuron finely punctate, anterior angles with long yellow setation. Prosternum finely punctate. Mesosternum finely punctate, mesosternal bulge. Metasternum finely punctate. Visible abdominal ventrites very finely punctate and covered by long yellow setae. First abdominal ventrite without anterior, longitudinal striation. Legs brown, covered by yellow setae.
Variability. Body measurements (mm): TL 2.5-2.9, PW 1.5-1.9, EW 1.5-1.9. Differential diagnosis. The new species belong to the castaneus species group, from Saudi Arabia. There is currently only one known species, Thorictus arabicus Háva, 2010 but the new species differs from it in the abovementioned characteristics.
Geographical distribution. This new Thorictini species is known from Najd Plateau, Central Saudi Arabia, Riyadh Province (Fig. 1), at Wadi Hanifah (Ad Diriyah), Rawdat Al Sabalh (Az Zulfi), and Rhodet Khorim (Ramah).  Description of holotype. Body small, brown covered by long yellow setae on dorsal surfaces and short setae on ventral surfaces. Measurements (mm): TL 2.8, PW 1.6, EW 1.6. Head finely punctate with long yellow setae. Labial palpi entirely brown. Antennae brown, with 11 antennomeres, antennal club compact with three antennomeres. Pronotum as finely punctate as head, covered by long yellow setation. Lateral margin of pronotum not dentate. Pronotum in posterior part near scutellum without bumps. Ventral posterior pronotal angles with long yellow setation. Scutellum not visible from above. Elytra very finely punctate covered by long yellow setation. Each elytron in anterior part near humeri with one very small bump. Epipleuron finely punctate, anterior angles with long yellow setation. Prosternum finely punctate. Mesosternum finely punctate, mesosternal bulge. Metasternum finely punctate. Visible abdominal ventrites very finely punctate, covered by long yellow setae. First abdominal ventrite with anterior, longitudinal striation. Legs brown, covered by yellow setae.
Differential diagnosis. The new species is similar to T. munganasti Reitter, 1908 (Egypt) but differs from it by the abovementioned characteristics.
Etymology. Named according to type locality: Wadi Hanifah. Ecological notes. This species was found in an area with loam texture, which is dominated by Tamarix senegalensis DC. (Tamaricaceae) and some Acacia gerrardii Benth. (Fabaceae) (Fig. 10) (Forel, 1902) in the same trap.
Geographical distribution. Thorictus hanifahensis Háva & Abdel-Dayem, sp. nov. is known only from its type locality in central Saudi Arabia, at Wadi Hanifah in the Ad Diriyah Governorate, Riyadh Province (Fig. 1). Chobaut, 1904 Remarks. Chobaut (1904) described the species from "Kasr-er-Rabbat in Arabia", a locality located in Jordan (Tronquet 1998). The species is excluded from the fauna of Saudi Arabia.   Description of holotype. Body small, brown covered by short yellow setae on dorsal surfaces and short setae on ventral surfaces. Measurements (mm): TL 2.1, PW 1.1, EW 1.2. Head finely punctate with short yellow setae. Labial palpi entirely brown. Antennae brown, with 11 antennomeres, antennal club compact with three antennomeres. Pronotum as finely punctate as head, covered by short yellow setation. Lateral margin of pronotum not dentate. Pronotum in posterior part near scutellum without bumps. Ventral posterior pronotal angles without long yellow setation. Scutellum not visible from above. Elytra very finely punctate covered by short yellow setation. Each   (Figs 13, 14). This new species was caught with ant species of Camponotus aegyptiacus (Emery, 1915), Crematogaster sp., Lepisiota obtusa (Emery, 1901), Monomorium jizane Collingwood & Agosti, 1996, Monomorium rabirium Bolton, 1987, Pheidole sp., andTetramorium simillium (Smith, 1851) in the same pitfall traps.  Description of holotype. Body small, brown covered by short yellow setae on dorsal surfaces and short setae on ventral surfaces. Measurements (mm): TL 2.1, PW 1.1, EW 1.2. Head finely punctate with short yellow setae. Labial palpi entirely brown. Antennae brown, with 11 antennomeres, antennal club compact with three antennomeres. Pronotum as finely punctate as head, covered by short yellow setation.  Lateral margin of pronotum not dentate. Pronotum in posterior part near scutellum without bumps. Ventral posterior pronotal angles without long yellow setation. Scutellum not visible from above. Elytra very finely punctate covered by short yellow setation. Each elytron in anterior part near humeri with one very small bump. Epi-   John, 1965 (Ethiopia), but differs from it by the abovementioned characteristics.

Thorictus peyerimhoffi
Etymology. The specific epithet is a Latinized noun in the genitive case in the masculine form based on the honorific name "Dr Mostafa Sharaf," who collected the specimens of this species.
Ecological notes. This new species inhabits areas at elevations of 1881-2324 m within the African pencil cedar forest, Juniperus procera Hochst. ex Endl. (Cupressaceae) in the Baha Province (Figs 17, 18). All specimens were collected by hand-picking under stones during May. Host unknown.
Geographical distribution. This species is known only from its type locality in the mountains of southwestern Saudi Arabia, at Alqamh Park, Amadan, and Shohba Forest in the Baha Province (Fig. 1).

Discussion
The study of the insect fauna of Saudi Arabia began with Buttiker and Wittmer (1979) who surveyed insects throughout the country. These surveys leading the entomological exploration of Saudi Arabia carried on for well over a half century thereafter. However, the Thorictinae fauna remains insufficiently known due to a lack of adequate dedicated survey. Based on the examination of the literature records (Háva 2010(Háva , 2021Abdel-Dayem et al. 2017) and collected specimens, the total number of Thorictinae species known from Saudi Arabia now stands at six species (Table 1). These species belong to two genera Thorictodes Reitter, 1875 and Thorictus Germar, 1834 under two tribes Thaumaphrastini and Thorictini, respectively (Háva 2020a Chobaut, 1904(Háva 2010. Although the Arabian Peninsula occupies almost twice the area of Iran, the number of species recorded from the Arabian Peninsula (7 species Háva 2020a) is less than that recorded from Iran (10 species; Háva and Švarc 2020). No common species are shared between the two regions.
The male genitalia are very important for differential diagnoses in insect taxonomy. But interspecific variation in male genitalia within species of Thorictinae leads to prob-lems in the differential diagnosis of the aedeagi (John 1963). Thus, we did not investigate the male genitalia of the studied specimens in this work.
We reported the ant species captured with the beetle species from the same pitfall trap. The host species of ants were not recognized during this study due to the fact that these specimens were collected accidentally from field surveys. The Thoricuts species are phoretic and obligate myrmecophiles, either generalists or specialists (Lenoir et al. 2013) and they are considered detritivorous (Sánchez-Piñero and Gómez 1995). The members of Thorictus are generally associated with various Cataglyphis species (Lenoir et al. 2013).