Contribution to the knowledge of the clown beetle fauna of Lebanon, with a key to all species (Coleoptera, Histeridae)

Abstract The occurrence of histerids in Lebanon has received little specific attention. Hence, an aim to enrich the knowledge of this coleopteran family through a survey across different Lebanese regions in this work. Seventeen species belonging to the genera Atholus Thomson, 1859, Hemisaprinus Kryzhanovskij, 1976, Hister Linnaeus, 1758, Hypocacculus Bickhardt, 1914, Margarinotus Marseul, 1853, Saprinus Erichson, 1834, Tribalus Erichson, 1834, and Xenonychus Wollaston, 1864 were recorded. Specimens were sampled mainly with pitfall traps baited with ephemeral materials like pig dung, decayed fish, and pig carcasses. Several species were collected by sifting soil detritus, sand cascading, and other specialized techniques. Six newly recorded species for the Lebanese fauna are the necrophilous Hister sepulchralis Erichson, 1834, Hemisaprinus subvirescens (Ménétriés, 1832), Saprinus (Saprinus) externus (Fischer von Waldheim, 1823), Saprinus (Saprinus) figuratus Marseul, 1855, and Saprinus (Saprinus) niger (Motschulsky, 1849) all associated with rotting fish and dung, and the psammophilous Xenonychus tridens (Jacquelin du Val, 1853). With the exception of Hister sepulchralis, all these taxa belong to the Saprininae subfamily. A most likely undescribed species of Tribalus (Tribalus) (Tribalinae) has also been collected in detritus at wet places near rivers in Lebanon. Because of the complexity of the genus Tribalus, with possible numerous new species present in the circum-Mediterranean area, the Lebanese species is not described herein, pending a revision of the genus. This study advocates further research aimed at improving taxonomic and ecological knowledge of this coleopteran family in Lebanon. The number of Histeridae species currently known from Lebanon stands at 41; a key to all species including images is included.


Introduction
The interesting biodiversity of Lebanon is due to its complex topography and altitudinal diversity and its location at the eastern rim of the Mediterranean Sea (Khater and El-Hajj 2012). According to Khater and El-Hajj (2012), there is a need to complete the assessment of biodiversity in various biological sections, especially invertebrates, which includes in its vast majority the insects. The latter occupy most ecological niches and are considered very important to the dynamics of natural ecosystems' structure and function (Fagundes et al. 2011;Cajaiba et al. 2017). Preserving their abundance and diversity should constitute a prime conservation priority. Coleoptera is the largest hexapodan order with ca. 400,000 described species worldwide, which comprise 40% of all described insect species (Fagundes et al. 2011;Gimmel and Ferro 2018). Carrion, animal droppings, dead wood, bird nests, mushrooms, and ant and termite nests are examples of such microhabitats (Bajerlein 2009; Barbosa and Vasconcelos 2018). The physicochemical conditions of these microhabitats are fleeting and rapidly changing, but they are rich in organic matter and colonized by insects of various guilds: coprophagous or necrophagous species, parasitoids and predators (Bajerlein et al. 2011). Among the beetle fauna associated with cadavers and animal droppings, predation is the main force structuring communities (Goff 2009;Bajerlein et al. 2011). Many Histeridae specialize on these microhabitats and are considered predictable components of carrion and dung communities (Bajerlein et al. 2011). In addition, histerids can be found under bark, in sand, in the galleries of wood-boring insects, and as important predators in stored products (Polat and Yıldırım 2017).
Histeridae may fulfil important practical roles (Kovarik and Caterino 2016). Many Histeridae adults and larvae are necrophilous, feeding mainly on dipteran larvae present on carrion or dung (Caneparo et al. 2017;Szelecz et al. 2018). Some are general predators of mites, insects and insect larvae, while other species are specific feeders on larvae of a single insect species (Szelecz et al. 2018). During carrion decomposition, histerids arrive in large numbers when fly larvae are abundant, i.e., during the active decay and early advanced decay stages (Caneparo et al. 2017;Shayya et al. 2018;Szelecz et al. 2018). Since the predatory taxa are abundant at different stages of decomposition, the knowledge of both their occurrence and the rates of decomposition aids in estimating the minimum postmortem interval PMI min on the basis of entomofaunal succession (Caneparo et al. 2017). The latter method could be the only accessible tool for estimating the PMI min when the PMI is longer than several months or even years (Amendt et al. 2011). Other predatory species of Histeridae have been introduced to augment control of dung-breeding flies (Davis 1994). necessarily associated to the ephemeral resources. A checklist of species, as well as key to all Lebanese Histeridae (including images of all species) are provided.

Materials and methods
The majority of specimens were collected in pitfall traps (28 cm height and 16 cm width) baited with rotting fish and pig dung. Specimens were collected after one week of placing the pitfall trap in each locality. The localities and their coordinates are mentioned in Table 1. Collection of specimens was also done during field trips in Baissour, Rechmaya, and Tyre. In Baissour and Rechmaya, the specimens were collected from under stones on the riverside and through sifting soil detritus. In Tyre samples were collected through sand cascading on the beach. Quantitative data on Atholus, Margarinotus, and Hypocacculus were recorded from sampling pitfall traps baited by pig carcasses.
General observations and dissections were carried out using stereomicroscope Nikon SMZ1500. Without genital extraction, males of Saprinus species can be usually recognized through the examination of the anterior tarsal setae, which are expanded and lamellate, whereas they are unexpanded and pointed in female. Often the males possess a longitudinal depression on the metaventrite and occasionally also a single or two tiny tubercles on the apical metaventral margin. Male genitalia were first macerated in 10% KOH solution for ca. 3 hours, cleared in 80% ethanol, macerated in lactic acid with fuchsine, incubated at 60 °C for another 30 min, subsequently cleared in 80 % ethanol, and then observed in α-terpineol in a small dish. Digital photographs of male genitalia were taken by a Nikon 4500 Coolpix camera and edited in Adobe  Mazur (2011); species within higher taxa are aligned alphabetically. For the morphological terminology the reader is referred to Ôhara (1994) and especially Lackner (2010). The general distribution of Histeridae in the Middle East is extrapolated from Lackner et al. (2015). Specimens were identified using the key of Kryzhanovskij and Reichardt (1976) as well as comparing them with reliably identified voucher specimens deposited in the collection of T. Lackner. The maps of species distribution were made using Google maps and Microsoft Visual Studio Code (Version 1.37).

Results
List of species recorded from Lebanon; their distribution in the Middle East and biology are mentioned. The list records are based on the Palaearctic catalogue (Lackner et al. 2015) and on our sampling efforts from ephemeral resources, viz. pig carrion, pig dung, and other manual collecting. The species distributions across Lebanese localities are presented on geographic maps. In addition, the checklist, a key, and images of all Histeridae species of Lebanon are provided.

Histeridae Gyllenhal, 1808 of Lebanon
Subfamily Abraeinae W.S. Macleay, 1819 Distribution. The subfamily contains five tribes and is distributed worldwide (Mazur 2011). In Lebanon, so far only one species of the tribe Teretriini Bickhardt, 1914 has been recorded.
Biology. Members of the Abraeinae subfamily are often found under bark, in rotting wood, inside galleries of xylophagous insects; in the case of Acritini it is decaying vegetable matter that they frequent the most (Kryzhanovskij and Reichardt 1976).
Biology. This species occurs under the bark of coniferous trees, especially pines, where it presumably preys upon larvae of xylophagous insects (Kryzhanovskij and Reichardt 1976).
Subfamily Dendrophilinae Reitter, 1909 Distribution. This subfamily contains four tribes and is distributed worldwide (Mazur 2011). In Lebanon, so far only two representatives of the tribe Bacaniini Kryzhanovskij, 1976 have been recorded.
Biology. The biology of Dendrophilinae is similar to that of Abraeinae, with most taxa being true dendrophiles and several taxa occurring on dung of herbivore mammals (e.g., Xestipyge Marseul, 1862).
Biology. Abraeomorphus species occur in rotting wood, often under bark (Kryzhanovskij and Reichardt 1976). Figure 16 Distribution in the Middle East. Israel, Lebanon .

Abraeomorphus besucheti Mazur, 1977
Biology. As with the general biology of the genus. Figure 17 Distribution in the Middle East. Lebanon .
Biology. Members of the subfamily are most-commonly found across humid and warm lowland forests, but several taxa are also encountered along streams or rivers.
These beetles are often hidden in decaying vegetable debris, but can also be collected from under bark (Kovarik and Caterino 2016;T. Lackner, pers. obs.). According to P.W. Kovarik (pers. comm. 2019) most of the Tribalinae are associated with rotting tree trunks or leaf litter where the larvae prey on soft-bodied insects and adults feed on fungal spores as well as soft-bodied insects.

Tribalus Erichson, 1834
Tribalus (Tribalus) sp. Figures 3, 120 Distribution. Tribalus contains 65 described species divided into two subgenera and is considered a species-rich genus (Lackner and Vienna 2017). The bulk of its representatives occur in Africa, while a smaller number of taxa are present in the Palaearctic and Oriental regions (Mazur 2011). We collected a presumably undescribed species, which represents the first occurrence of this genus for Lebanon,in Baissour,Fanar,and Rechmaya (Figs 120,126).
Biology. Members of Tribalus are found mostly under stones in wetter areas near streams. They can be occasionally collected by sifting forest detritus as well (T. Lackner, pers. obs.). We collected 20 specimens of an unidentified species of Tribalus from under stones and tree bark, respectively, in wet areas near rivers of Baissour (8 specimens) and Rechmaya (12 specimens).

Subfamily Histerinae Gyllenhal, 1808
Distribution. Worldwide (Mazur 2011). The subfamily comprises five tribes: Exosternini Bickhardt, 1914;Histerini Gyllenhal, 1808;Hololeptini Hope, 1840;Omalodini Kryzhanovskij, 1972 andPlatysomatini Bickhardt, 1914. The tribe Omalodini is almost exclusively Neotropical and no member of the otherwise widely distributed Hololeptini has been recorded from Lebanon hitherto. Regarding the Platysomatini, only the subcortical species Platylister (Popinus) simeani (Mulsant & Godart, 1875) and Platysoma (Cylister) cornix Marseul, 1861 have yet been recorded from Lebanon. On the other hand, likewise subcortical species Platysoma (Platysoma) compressum (Herbst, 1783) and P. (P.) inexpectatum Lackner, 2004 have been recorded from neighboring Syria; their occurrence in Lebanon therefore cannot be ruled out. As mentioned in the introduction, a single member of the otherwise oriental genus Notodoma Lacordaire, 1854, N. lewisi Reitter, 1910 has been recorded from Lebanon; this species is otherwise also known from Turkey (Lackner and Hlaváč 2002). A strictly myrmecophilous species Spathochus coyei Marseul, 1864 is known from neighboring Syria and Israel, as well as Cyprus or Turkey (Lackner 2009), making its occurrence in Lebanon highly likely. We therefore decided to depict this highly charismatic ant inquiline here as well as include it in the key. The tribe Histerini is the most-widely distributed and most species-rich tribe of the subfamily worldwide.
Biology. Members of Histerini are most often encountered on decomposing organic matter, such as manure, dung, compost heaps, decaying vegetables, but are also found on carrion and rotting mushrooms. Inquilinous members are also rather numerous in the subfamily, especially in the Palaearctic, Nearctic and Neotropical regions (Kryzhanovskij and Reichardt 1976). Platysomatini are subcortical as a rule, while Exosternini have varied habits and include fungivores, inquilines and dendrophiles alike (Kovarik and Caterino 2016).
Biology. Mostly found in and on rotting mushrooms where it preys on Diptera that develop on rotting fungi and basidiomycete mushrooms (Kovarik and Caterino 2016). Figure 5 Distribution in the Middle East. Lebanon, Syria, Turkey . Described from "Hochsyrien, bei Akbes" (Reitter 1910). This locality (Akbès = Meydan Ekbaz) probably does not lie in Lebanon, but in Turkey, right on the Syrian-Turkish border, between the Turkish town Osmaniye and Syrian town of Aleppo. Lackner and Hlaváč (2002) reported a specimen from south-eastern Turkey (Arslanlı, near Erdemli; misspelled as "Arsanli" in their publication) -their locality is actually quite close to the type locality of this species. Most likely, Notodoma lewisi does not occur in Lebanon, but since it has been included in all major catalogues of Histeridae (e.g., Mazur 2011) as described from Lebanon, we decided to keep it here pending further investigation.

Tribe Histerini Gyllenhal, 1808
Atholus Thomson, 1859 Distribution. The genus Atholus comprises 78 species that inhabit Holarctic, Afrotropical and Oriental regions (Mazur 2011). Biology. Members of Atholus can be found in decomposing carrion and dung, but are commonly found also under stones and in animal burrows (Penati 2009). Members among this genus can be attracted to Euphorbia in xeric areas and to rotting roots of Apiaceae and Fabaceae (Kovarik and Caterino 2016  . Previously reported from Lebanon from Badghan (Shayya et al. 2018) (Fig. 121).
Biology. This species shows a preference for dung that has lost much of its moisture; it has likewise been found in association with various stored products where it likely preys on beetle larvae feeding on these materials (Bajerlein 2009;Kovarik and Caterino 2016;Mazur et al. 2017). In Lebanon, A. duodecimstriatus duodecimstriatus was attracted to carrion (Shayya et al. 2018). A very common species in Lebanon.

Hister Linnaeus, 1758
Distribution. Hister is the most species-rich genus of the family and comprises 195 species; these can be found in all world regions, with the exception of Antarctica (Mazur 2011).
Biology. Hister shows preference for dung, but can also be associated with carrion, while some species feed on dung beetle larvae (Coleoptera: Scarabaeidae) present in dung (Kovarik and Caterino 2016). Figure 11 Distribution in the Middle East. Lebanon, Syria, Turkey .

Hister sepulchralis Erichson, 1834 Figures 12, 121
Distribution in the Middle East. Iran, Jordan, Lebanon, Syria, Turkey . Herein it is reported from Lebanon for the first time from Kfar Kouq ( Fig. 121, 126). Biology. Hister sepulchralis occurs most often in cattle dung (Rozner 2010) and, like other Hister species, it requires liquid fraction from dung to have disappeared to oviposit (Kovarik and Caterino 2016). We collected a singleton of this species from a pig dung-baited pitfall trap. A sporadic and uncommon species in Lebanon.

Margarinotus Marseul, 1853
Distribution. Margarinotus includes ten subgenera containing 109 species altogether, found predominantly in the Holarctic region; several species are likewise autochthonous to the Oriental region (Mazur 2011).
Biology. Taxa grouped in Margarinotus are varied in their habitat preferences. Several species are linked to carrion or dung, while others prefer rodent burrows (Caterino 2010;Kovarik and Caterino 2016).
Biology. This species shows a clear preference for carrion (Kovarik and Caterino 2016), and has previously been reported from pig carcasses (Matuszewski et al. 2008) as well as from dung (Rozner 2010;Mazur et al. 2017). In Lebanon M. (P.) brunneus was collected from carrion during spring in Fanar (50 specimens) and Naas (181 specimens). It was also collected during the same season from rotting fish-baited pitfall traps in Kfeir (1 specimen), Mimes (1 specimen), and Nabaa Al Safa (6 specimens). A very common and widespread species in Lebanon.
Biology. Often found in decaying wood in the company of various Formicidae (Lasius spp. and Formica spp.); it has likewise been known to occur on excrement (Sanchez and Chittaro 2018). In our study, a singleton of M. (G.) ruficornis was collected from carrion during spring in Fanar.

Biology.
Members of Platylister are collected under bark of trees, where they prey on (the larvae of ) subcortical insects (Kryzhanovskij and Reichardt 1976). Figure 7 Distribution in the Middle East. Lebanon, Turkey, United Arab Emirates .

Platysoma Leach, 1817
Distribution. Platysoma contains three subgenera and is spread across the whole world, albeit only a single species is known from South America (Mazur 2011).
Biology. Associated with bark of trees, where it preys upon members of subcortical insect communities (Kovarik and Caterino 2016). Figure 8 Distribution in the Middle East. Cyprus, Israel, Lebanon, Syria, Turkey (Lackner et al. 2015).

Onthophilinae Macleay, 1891
Distribution. Worldwide (Mazur 2011). Biology. Members of Onthophilinae have varied habits. They occur in decaying vegetable matter, on dung, and on rotting mushrooms, but the subfamily likewise contains dendrophilous and nidicolous species (Kovarik and Caterino 2016).

Onthophilus Leach, 1817
Distribution. Onthophilus is predominantly Holarctic in distribution, with several species known also from Central America and a single Australian species (Mazur 2011).
Biology. Adults prey on fly eggs (but not larvae) and filter feed on the liquid coating of fresh dung; some are known to prey on Diptera that develop on rotting fungi. Their mouthparts bear modified setae that seem to strain particles from liquid (Kovarik and Caterino 2016). Figure 1 Distribution in the Middle East. Israel, Lebanon, Turkey .

Onthophilus bickhardti Reitter, 1909
Biology. Biology of this rare species is unknown, but most specimens have been collected during November by pitfall traps in higher elevations in Lebanon (Lackner, unpublished). Figure 2 Distribution in the Middle East. Cyprus, Israel, Jordan, Lebanon, Syria, Turkey .
Biology. Saprininae have witnessed a remarkable ecological evolution. They are known as colonizers of different ecological niches: ant-nests, dead termitaria, rodent burrows etc. They even gained fine morphological adaptations and distribution throughout Old World deserts. In addition, members of Saprininae have colonized mammal burrows, nests of birds, ants, termites, and even tortoise burrows. Their life histories are varied, as several lineages exhibit diversity in their terrestrial niches (Lackner 2014a).
Biology. Members of Chalcionellus are found in manure, in excrements and on carcasses; the genus contains also a single species occupying the rhizosphere of plants (Kryzhanovskij and Reichardt 1976). Figure 20 Distribution in the Middle East. Iran, Iraq, Israel, Lebanon, Syria, Turkey .

Gnathoncus Jacquelin du Val, 1857
Distribution. Predominantly Holarctic in distribution; a single species is known from tropical Africa (Mazur 2011). From the Oriental region a handful of cave-dwelling species have been recorded (Lackner 2020). Biology. Members of Gnathoncus occur predominantly in bird nests or burrows of smaller mammals; occasionally they are found also on carrion or decomposing vegetable matter (Kryzhanovskij and Reichardt 1976). Figure 22 Distribution in the Middle East. Lebanon, Syria, Turkey .
Biology. Taxa included in Hypocacculus are typically collected from carrion and animal excrement and usually found in dry and arid regions. Also, they can be collected in open landscapes and some are psammophiles (Lackner 2010).
Biology. This species is found in association with small animal carcasses, excrements and other decomposing matter. It also found on coastal dunes in the rhizosphere of psammophilous Graminaceae (Penati 2009). It is a generalist predator (Lackner 2014a). Already reported from Lebanon (Shayya et al. 2018). Figure 24 Distribution in the Middle East. Cyprus, Iran, Israel, Lebanon, Oman, Saudi Arabia, Syria, Turkey, United Arab Emirates, Yemen .
Biology. Members of Hypocaccus s. str. and Baeckmanniolus are coastal wrack specialists, occasionally occurring also on banks of rivers and lakes, while members of the subgenus Nessus are typical generalist predators with several psammophile or inquiline forms (Kryzhanovskij and Reichardt 1976). Figure 26 Distribution in the Middle East. Cyprus, Israel, Lebanon, Syria .

Saprinus Erichson, 1834
Distribution. Saprinus includes two subgenera Phaonius Reichardt, 1941 and Saprinus s.str. and 157 species distributed around the world (Mazur 2011). With 116 species in the Palaearctic region and 14 species in Lebanon, it is the most species-rich genus of the Saprininae (Lackner 2010, Shayya et al. 2018). Moreover, this study adds three new species records of this genus for the Lebanese fauna. Most of the Saprinus species occur in the Palaearctic and Afrotropical regions (Lackner 2010). Biology. Saprinus shows preference to open xeric landscapes and only few are known from mesic biotopes (Lackner 2010). They are frequent on carrion and less so on dung, and prey on larvae and eggs of soft-bodied insects; in some cases they can capture adult flies on dung (Carlton et al. 1996). Some species could also be found on flowers (Lackner 2010;Kovarik and Caterino 2016).
Biology. This species is present on carcasses, in excrements, manure, mammal burrows and occasionally even on flowers (Kryzhanovskij and Reichardt 1976 (Fig. 122).

Saprinus (Saprinus) externus (Fischer von Waldheim, 1823)
Biology. Found among carrion entomofauna at various stages of decomposition, especially in rural areas (Al Tunsoy et al. 2017). Saprinus (S.) externus is an infrequent taxon in Lebanon. According to Reichardt (1941), this species is linked to carrion and dung. In our samplings, a singleton was reported from pig dung-baited pitfall trap in Kfar Kouq and another was collected in decomposing fish-baited pitfall trap in Rashaya (Fig. 123).

Xenonychus
Biology. The first two species are inhabitants of arid areas of shifting sand, frequent on sand dunes on beaches and also present inland. The biology of the X. somaliensis is unknown, but presumably similar to congeners (Lackner 2012  . New to Lebanon (Tyre) (Fig. 125).
Biology. A typical psammo-halobiotic species, usually found under plants on coastal as well as inland dunes; occasionally found also under carrion on sandy surfaces (T. Lackner, pers. obs. 2012). According to Reichardt (1941), it was examined in dune sands of the sea coast at a depth of 15 to 30 cm of a raw layer of sand and in the vicinity of plants roots. During sand-cascading at the Tyre beach, 12 specimens were collected in the rhizosphere of various plants.

Checklist of the Histeridae of Lebanon and surrounding countries
This checklist is based on Lackner et al. (2015) as the main reference; other relevant sources of information included Mazur (2011) and Shayya et al. (2018) (Table 2).

Discussion
In general, faunistic inventories are incomplete since the number of studied species continues to increase with the increase of sampling efforts (Baz et al. 2014 The key provided in this study provides a foundation for the identification of histerids from Lebanon for other entomological and ecological studies in the country. The following are comments on species biology and some implications.

Species attracted to ephemeral microhabitats that could be of forensic relevance
Saprinus and Margarinotus are dominant genera on ephemeral and unstable microhabitats like carcasses, dung, and decaying plants (Mazur 1981;Bajerlein et al. 2011). Many species belonging to these two genera are considered eurytopic, able to tolerate a wide range of microhabitats (Bajerlein 2011). Species among these genera were found to oviposit their eggs near the carcass, where there is no larval mass and the soil temperature is cooler (Bajerlein et al. 2011;Caneparo et al. 2017). Saprinus (S.) subnitescens was the most abundant species on pig carrion (Shayya et al. 2018). In our samplings, this species was also abundant on rotting fish-baited pitfall traps especially in Shouf-Aley region and it was also present on dung in Kfeir. Also, Saprinus (S.) strigil was common on decomposing pig carcasses (Shayya et al. 2018). It was also associated with other ephemeral microhabitats used in this study. Saprinus (S.) chalcites, Saprinus (S.) godet, Saprinus (S.) robustus, Saprinus (S.) tenuistrius sparsutus were also attracted to dung, decomposing fish and to carrion (Shayya et al. 2018). Saprinus (S.) caerulescens was only attracted to mammalian carrion and it was absent from other baits (rotting fish and dung). This is in accordance with T. Lackner's personal observation that this species is common on large carcasses. However, Kryzhanovskij and Reichardt (1976) collected this species on rotten fish, where it preyed upon dermestids, whereas Anlaş et al. (2007) collected it from cow dung in Turkey. The preference of this species to a specific microhabitat should be further investigated in future studies.
Margarinotus spp. are varied in habits (Caterino 2010). In our samplings (Mediterranean climate), they were present on carrion only in spring; absent in summer. They were less frequent in rotting fish-baited pitfall traps. Despite the differences in climate, this is in accordance with Bajerlein et al. (2011), who found that their abundance was highest in spring, and decreased markedly in summer in a study in West Poland, a temperate climate. Also, Kočárek's (2003) work supported the highest abundance of histerids in spring during a study in the warm and temperate climate of Opava, Czech Republic. Margarinotus likewise shows preference to cold and humid forest floor (Bajerlein et al. 2011). The latter condition is common especially in early spring in Lebanon (Abi Saab et al. 2019).
Atholus duodecimstriatus duodecimstriatus was collected from carrion only during summer. Unlike the findings of Bajerlein (2009) and the review of Kovarik and Caterino (2016), which mentioned the preference of this species to dung, it was absent from other ephemeral microhabitats of this study. Similarly, Hypocacculus (H.) metallescens was rare and collected during summer from carrion and absent from other decomposing matter, dung, and sand dunes, which it is normally associated with (Penati 2009). Thus, more sampling efforts should be made to elucidate the habitat preference of these two species. Hister is mainly found in cattle and horse dung (Rozner 2010). This is in accordance with our study as Hister sepulchralis was absent from carrion and only attracted to pig dung. However, the arrival of Hister spp. on carrion during the active decay stage and their presence in the advanced decay and dry stages, as reported by Wolff et al. (2001), was not observed during our sampling from decomposing carrion in Lebanon. Chalcionellus spp. were previously recorded from Lebanon, but absent from our collecting. They are usually attracted to excrements and decomposing carcasses (Kryzhanovskij and Reichardt 1976).
According to Nuorteva (1970), histerids, especially those among the genera Saprinus and Hister are attracted to fish carcasses later than blowflies, predate on fly egg and larvae and even destroy the full-grown fly larvae. Thus, there is a negative correlation between the occurrence of blowflies and histerids on fish carcasses (Nuorteva 1970). In our collections, Saprinus (S.) figuratus was found only on fish carcasses and not on pig ones. In a similar Mediterranean climate, in Spain, this species was found to be rare and restricted to mesomediterranean holm oak forests (Martín-Vega et al. 2015). Un-like the findings of Reichardt (1941), Saprinus (S.) niger was also collected only from fish carcasses and not from other carrion. In Spain, it was found also on squid carcasses, which are effective for collecting carrion insects and species inventories resemble those from pig studies (Martín-Vega et al. 2015). Al-Tunsoy et al. (2017) suggested that Saprinus (S.) externus is uncommon in Turkey and that carrion is not its primary habitat. Also, Rozner (2010) mentioned that it is very rare. In our samplings we found two specimens on dung and fish but none on pig carrion.

Species collected from humid habitats
The subgenus Tribalus s. str. of the genus Tribalus is a species-rich group mostly occurring in Africa with smaller number of species found in the Palaearctic and Oriental regions (Mazur 2011;Lackner and Vienna 2017). Similar to the findings Lackner and Vienna (2017), we found this genus under stones in wetter areas on the riverside of Baissour and Rechmaya rivers and also in the soil detritus at Rechmaya riverside. Also, Lackner and Chehlarov (2006) found it in pitfall traps on the right shore of Struma River in Bulgaria. Kovarik and Caterino (2016) mentioned that this genus is attracted to organic material beneath old dead trees and to rotting wood. They likewise mentioned that Tribalus (T.) capensis (Paykull, 1811) shows preference to dung that has lost much of its moisture and that Tribalus (T.) cavernicola Lewis, 1908 occurs in cave entrances. Those two species of Tribalus are not found in the Palaearctic region . The subgenus contains many undescribed, externally rather uniform species that can be most-reliably separated based on their male genitalia (Lackner and Vienna 2017). It is therefore and due to the lack of reliable taxonomic keys we didn't assign the exact taxonomic identification and we advocate its revision.

Ultra-psammophilic species
The genus Xenonychus is an ultra-psammophilic group, which is found exclusively in sand dune systems. They are buried in sand and known as sand-swimmers. They can be found by laborious methods near the roots of plants . According to the personal observation of T.L., members of Xenonychus could be found on carrion that is on sand or buried in it. Also, Hypocacculus (C.) praecox is a psammohalobiotic species (Penati 2009). We found Xenonychus tridens on a sandy beach in Tyre (Lebanon). It is important to study the entomofauna associated with carcasses on the seashore or those buried in sand, which could help in estimating the minimum postmortem interval (PMI min ). For instance, in 2018 a murdered woman was found covered with sand in Sidon Rmeileh beach-Lebanon (Zaatari 2018).

Species attracted to decaying plants, trees bark, and fungi
Abraeomorphus minutissimus, Eudiplister castaneus, Margarinotus (Grammostethus) ruficornis, Platysoma (Cylister) cornix, and Platylister (Popinus) simeani are often associated with decaying plant matter and/or bark of trees like pine (Kryzhanovskij and Reichardt 1976;Kovarik and Caterino 2016). Notodoma lewisi is a fungivorous species. Fungi can provide insects with nutrients and essential elements, and in recently dead wood they detoxify plant defenses and provide protection (Birkemoe et al. 2018). Such beetles might serve as a dispersal vector for dead-wood-inhabiting fungi. More knowledge on such interaction is detailed in Seibold et al. (2019).

Conclusions
This is considered the first faunistic study of the Histeridae family in Lebanon with a key to all locally recorded species, comments on their biology, and possible implications in the country of study. More ecological research should be performed in different Lebanese regions and more quantitative data are needed to clarify the habitat preference of Histeridae species. Different sampling methods such as sifting, Flight Interception Traps (FIT), pitfall traps, etc. should be also used in the future. Seasonal sampling and replicates are needed to show the peak activity, seasonality, and habitat preferences of members of this family.