The beetle fauna (Insecta, Coleoptera) of the Rawdhat Khorim National Park, Central Saudi Arabia

Abstract This study was conducted as a part of a comprehensive baseline survey of insect biodiversity of Rawdhat Khorim National Park (RKNP), Central Kingdom of Saudi Arabia (KSA). During this study a total of 262 Coleoptera species belong to 182 genera in 35 families were identified, of which 247 are named at a species level. Fifteen species (6.0%) are apparently endemic to KSA. Thirty-eight species are new to the known beetle fauna of KSA, including 25 species reported from the Arabian Peninsula for the first time. The families Tenebrionidae (45 species), Scarabaeidae (34 species), and Carabidae (27 species) were the most species rich families. About 37% of the beetle abundance was represented by species of Scarabaeidae, especially Aphodius ictericus ghardimaouensis Balthasar. Karumia inaequalis Pic (Dascillidae) was also an abundant species. Approximately 43.5% of beetle species collected during this study are considered very rare taxa in RKNP. The RKNP beetle fauna shows more affinity to Sahro-Arabian (36.4%), Afrotropical-Sahro-Arabian (17.4%) and Palaearctic-Sahro-Arabian (10.5%). Twenty-three species (9.3%) are considered cosmopolitan or subcosmopolitan. The data on month of collection, method of collection, and abundance status within RKNP, together with the distribution within KSA and the general distribution (zoogeography) of each species are presented.


Introduction
Beetles (Coleoptera) are considered the most taxonomically diverse insect group that comprises major components of ecosystems in terms of biomass, species richness and ecological roles (Stack 2015). About 400,000 species have been described (Hammond 1992), comprising about 25% of the Earth's total animal diversity (Rosenzweig 1995;Hunt et al. 2007). Beetles play important roles in pollination, herbivory, granivory, predator-prey interactions, decomposition and nutrient cycling, and soil disturbances (Huffaker and Gutierrez 1999).
The foundation of our knowledge of the beetles of the Kingdom of Saudi Arabia (KSA) was presented by various authors in the series "Fauna of Saudi Arabia," currently published as part of the "Fauna of Arabia" (Wittmer and Buttiker 1979-to date). Additionally, sixteen years ago, Al-Ahmadi and Salem (1999) listed 1,343 beetle species from KSA. Additional data on the beetles in KSA are available in the Catalogue of Palaearctic Coleoptera (Löbl andSmetana 2003-2007).
Rawdhats, naturally occurring moist basins, are one of the major components that considered as biological cores in the hyper-arid ecosystems of Central KSA (Tag El-Din et al. 1994;Al-Farraj et al. 1997;Alfarhan 2001;Al-Qarawi 2011). The flora and fauna of these unique habitats are under constant threat due to increased anthropogenic activities (Al-Nafie 2007;Al-Qarawi 2011). However, relatively little is known about their insect fauna (e.g., Al Platia 2013, Al Dhafer et al. 2016;Sharaf et al. 2013;Alqarni et al. 2015;Abdel-Dayem et al. 2015) that contribute to the faunal biodiversity of KSA.
The objective of the current study was to provide a comprehensive list of the beetles from one of the more unique habitats in the world, specifically RKNP contributing to the knowledge of the beetle fauna of KSA and the Arabian Peninsula in general.

Study area
The Rawdhat Khorim National Park is situated in the northeastern Riyadh Province of Central KSA (Fig. 1a). This is part of the Najd Plateau, a sedimentary rectangular plateau of Saudi Arabia. It covers an area of 24 km 2 and located about 95 km northeast of the capital of Riyadh (25°23'N, 47°17'E, 560 m.a.s.l.). It is a densely vegetated alluvial basin (Vesey-Fizberald 1957) (Figure 1b) supporting a characteristic floral community in the hyper-arid desert of central Saudi Arabia (Al-Farraj et al. 1997;Alfarhan 2001). This area has low rainfall, but drainage from surrounding foothills of the adjacent highlands provides additional moisture forming temporary water pools and high plant diversity occurs during spring (Al-Farraj et al. 1997).

Climate
The climate of RKNP is characterized by a hot summer and a mild winter with an average relative humidity of 33%. The average annual temperature is 26°C, June to August is the hottest period of the year (35-37.4 °C) and December to February is the coldest (14.6-15.7 °C). The average annual precipitation is 122 mm, the highest amount of precipitation occurs during March and April (30 and 27 mm, respectively), while no rainfall occurs during June to September .

Flora
The flora of RKNP includes a total of 153 plant species belonging to 32 families (Alfarhan 2001). The vegetation is complex consisting of perennial and annual herbs, shrubs and trees (Al-Farraj et al. 1997 (Al-Farraj et al. 1997). Plant growth is higher during spring than in other seasons (Al-Farraj et al. 1997).

Beetle collection
The species listed here are based on the survey that was conducted biweekly from October, 2011to September, 2013 in the RKNP. The material was collected using a variety   The RKNP beetle fauna demonstrated variable zoogeographical affinities ( Figure  2), 15 species (6.1%) are endemic to KSA. The remainder of the species showed high affinities to SAR (36.4%), AFR_SAR (17.4%), and PAL_SAR (10.5%).
It is expected that the results of this study of the beetle fauna of RKNP will be used for future studies related to long-term monitoring of the beetle fauna for evaluating impacts of increased use by the growing population of nearby Riyadh and impact of climate change (Bale et al. 2002).
General distribution. SAR. Local distribution. EP (Brancucci 1984). Collecting month and method. Frequent species that was collected by LT in VI. General distribution. AFR_SAR. Local distribution. EP (Mazur 1994;Penati and Vienna 2006). Collecting month and method. Very rare species that was collected by BV on branches of Z. nummularia during V.

Subfamily: Sapriniae
Pholioxenus sp.1 Collecting month and method. A rare species. The specimens were collected by PT under canopy of A. ehrenbergiana, A. gerrardii and R. stricta during IV-V and X.

Pholioxenus sp.2
Collecting month and method. Frequent species. The beetles were collected by PT under canopies of A. ehrenbergiana, A. gerrardii, C. procera, L. shawii, R. stricta and Z. nummularia; and by LT through V-XI.
Collecting month and method. Very rare species that was collected by LT in IV-V and VII.
General distribution. SAR. Collecting month and method. Very rare species, which was collected by LT during VII.
Collecting month and method. Very rare species. It was collected by PT under canopy of Z. nummularia in III. Local distribution. RI (Beccari 1971). Collecting month and method. Very rare species that was collected by LT during X. Collecting month and method. Very rare species, which was collected by LT through XII.

Carpelimus sp.
Collecting month and method. Very rare species that was collected by LT in VII.
Collecting month and method. Very rare species that was collected by LT through VI.
General distribution. SAR. Local distribution. EP, RI (Paulian 1980). Collecting month and method. Very rare species that was collected by LT during V.
Collecting month and method. Very rare species that was collected by LT in IV.
Collecting month and method. Very rare species that was collected by LT in IV.  (Beccari 1971, Kuijten 1980. Collecting month and method. An abundant species. The adult beetles were collected by HP, LT and PT through II, IV-VIII.
General distribution. SAR. Collecting month and method. Very rare species that collected by LT during V. Collecting month and method. A frequent species. The adults of this species were collected by PT under canopy of A. ehrenbergiana, and by HP and LT during I-II, IV-VII and IX.
General distribution. AFR_SAR. Local distribution. The species was reported from Arabia without exact locality (Pittino 1984) and recently its occurrence in KSA: RI has been confirmed by Abdel-Dayem et al. (2016).
Collecting month and method. Very rare species that was collected by LT during IV.
Collecting month and method. Common species that was collected by LT through V-VII and IX-X.
General distribution. SAR. Local distribution. EP, RI (Pittino 1984). Collecting month and method. A rare species, which was collected by LT in I and XII. Collecting month and method. Common species. The specimens of this species were collected by PT under canopies of A. ehrenbergiana, A. gerrardii, L. shawii, R. stricta and Z. nummularia; and by LT through IV-V and IX-X.
Collecting month and method. A common species. The adult beetles were collected by PT under canopies of A. ehrenbergiana, A. gerrardii, C. procera and R. stricta; and by HP and LT through III-V and XII.

Pseudomothon sp.
Collecting month and method. Rare species that was collected by LT during IV.

Rhyssemus granosus (Klug & Erichson
Collecting month and method. A rare species. The beetles were collected by LT through IV-V, VII and X. Pittino, 1984 World distribution. Asia: SA.
Collecting month and method. Common species. The adult beetles were collected by PT under canopies of C. procera, L. shawii, R. stricta and Z. nummularia; and by HP and LT through III-V and VII-XI. General distribution. AFR_ORR_SAR. Local distribution. AS, EP, RI (Paulian 1980). Collecting month and method. Rare species, which was collected during V.

Trichosphaena arabica
General distribution. SAR. Local distribution. HA, JZ, MK, NJ, QS, RI (Kaszab 1979(Kaszab 1981(Kaszab 1982. Collecting month and method. A frequent species. The adults of this species were collected by BV on branches of A. ehrenbergiana and Z. nummularia, and by HP during IV and VII-IX. Collecting month and method. Rare species. It was collected by PT under canopies of A. ehrenbergiana, C. procera, R. stricta, and Z. nummularia during III-IV, X and XII; also collected by LT during V. Collecting month and method. A rare species. The adult beetles were collected by BV on branches of Z. nummularia during II and V; and by LT through X. Caldara & Fremuth, 1992 World distribution. Asia: IQ, IR, JO, SA, TR. North Africa: EG.
Local distribution. EP, RI (Caldara 1993). Collecting month and method. Rare species. Its adult was collected by BV on branches of A. ehrenbergiana, A. gerrardii and Z. nummularia through XII; by PT under canopy of A. ehrenbergiana in XI; and by LT and MT during V and VII respectivelly.
Collecting month and method. Very rare species that was collected by PT under canopy of C. procers in II.
General distribution. SAR. Local distribution. AS, RI (Caldara 1993). Collecting month and method. A frequent species. The adults were collected by BV, SW and VC on branches of A. gerrardii, R. stricta and Z. nummularia during III-V; and by PT under canopy of A. ehrenbergiana during I-VI and XII.

Subfamily: Entiminae
Myllocerus sp. Collecting month and method. A rare species. It was collected by PT under canopies of R. stricta and Z. nummularia during I-II; and by HP and LT in I, IV and XII. Collecting month and method. Very rare species that was collected by LT in I, IV and XII.