Diversity of the longhorned beetles (Coleoptera: Cerambycidae) from Cuatro Ciénegas Basin, Coahuila, Mexico

Abstract Background Cerambycidae is one the most diverse families in the order Coleoptera with more than 37,000 species described in all continents. Cerambicyd beetles have a worldwide distribution from sea level to montane sites. In Mexico, more than 1,600 species have been recorded. Nevertheless, the diversity and distribution of this family in the Mexican deserts is poorly known. New information A first checklist of Cerambycidae from seven localities of Cuatro Ciénegas Basin is presented. This study is the result of sampling carried out between 2009 to 2013. Some material from other collections is also included. The species list includes four subfamilies, 13 tribes, 32 genera and 37 species, from which 13 are new records for the state of Coahuila and three species represent new records for Mexico. These results highlight the paucity of knowledge of insects in the deserts of Mexico.


Introduction
Cerambycidae comprise one of the largest families of Coleoptera, represented by more than 37,000 species, described in more than 5,300 genera from eight subfamilies (Monné et al. 2017, Tavakilian andChevillotte 2020). Cerambycid beetles are distributed worldwide wherever their hosts plants are found from sea level to montane sites as high as 4,200 m elevation (Bezark et al. 2013). Due to its ecological, biological and evolutionary importance, this family has been studied extensively. The diversity of the Cerambycidae in Mexico was summarised by Noguera (2014). However, knowledge of the diversity and distribution of the family Cerambycidae in the Mexican deserts is poor, with just some isolated records (Bezark 2020).
The Cuatro Ciénegas Basin (CCB) (Souza et al. 2012) is located at the south-eastern portion of the Chihuahuan Desert (Fig. 1). With more than 450,000 km , it is the largest desert in North America. This, along with its high biological diversity, makes it one of the most important deserts in the world (Morafka 1977). The CCB has a unique geological and biological history which dates from at least 40 mya in the Middle Eocene. At this point the region was isolated from the Atlantic Ocean by the rise of the Sierra Madre Oriental (Álvarez and Ojeda 2019). The subterranean water, which currently emerges, forms ponds and streams that distinguish this region from other surrounding desert areas. This, plus the isolation of the CCB, has resulted in a high degree of endemism in some taxonomic groups (Souza et al. 2012).
The fauna that occurs in the CCB is a mixture of species with Neotropical and Nearctic biogeographic origins or affinities. This important region of transition can represent the distributional limits of both groups (Souza et al. 2012, Álvarez andOjeda 2019). This work is a result of a study of diverse taxonomic groups in the CCB (Álvarez and Ojeda 2019), undertaken for the purpose of providing a better understanding of its local diversity. There are no published records of cerambycids from this region. This study is the first approach that aims to contribute to the general knowledge of this group in the Mexican deserts.
Fourteen field trips were performed during 2012 and 2013. Records from sporadic trips in 2009 and 2010 are also included. Sampling totalled 84 collecting days with at least three people collecting each day (09:00 to 16:00 h). Different sampling techniques (direct and indirect) were applied: by hand, sweep net and light traps. Cerambycid beetles were identified to species level with specialised literature (Chemsak 1991, Chemsak and Linsley  1965, Chemsak and Noguera 2005, Giesbert and Chemsak 1989, Giesbert and Chemsak 1993, Grzymala and Miller 2013, Linsley 1963, Linsley 1964, Linsley and Chemsak 1972, Noguera 2002, Santos-Silva 2007, Santos-Silva et al. 2016, Turnbow and Thomas 2002 and by comparison with identified specimens from the National Collection of Insects of the Biology Institute, UNAM. All specimens were deposited in the Insect Collection of the Zoological Museum "Alfonso L. Herrera" of the Faculty of Sciences, UNAM. The National Collection of Insects (CNIN) was revised and all the records belonging with CCB were included (Suppl. material 1).

Discussion
Despite the fact that Mexico has extensive area of deserts, faunistic studies relating to Cerambycidae have previously not been conducted in this or similar xerophilous habitats. In Mexico, the family Cerambycidae has been studied mainly in tropical dry forest (e.g. Noguera 1993, Noguera et al. 2012). Only sporadic records from desertic areas have been reported (Bezark 2020 (1987) argue that Lepturinae species depend on moisture for development, hence their species richness in arid environments is poor. On the another hand, Cerambycinae presents the greatest number of genera with diurnal habits (Linsley 1959). In the case of CCB, the genera of Cerambycinae were more common in daytime activity. This is presumably due to different types of adult feeding which is anthophilous in several genera of Cerambycinae (Švácha and Lawrence 2014 Possibly due in part to extensive collecting efforts, the states of Veracruz (406), Oaxaca (343), Jalisco (327) and Chiapas (315) (Noguera 2014) have the highest species records of Cerambycidae (numbers in parenthesis indicate the numbers of species recorded from Table 1. Number of tribes, genera and species of the cerambycids from Cuatro Ciénegas Basin the corresponding state). Noguera (2014) indicates the species richness from Coahuila at 24 species. Nevertheless, Bezark (2020) in the electronic catalogue of Cerambycidae recorded 43 species from Coahuila. Our work represents a considerable contribution and updated inventory of Mexican Cerambycidae in the Coahuila region. It presents new distributional records that represent a 41% increase in species richness. It is clear that it is necessary to continue exploring more regions of Mexico and publishing updated Cerambycidae distribution data to complete our knowledge, not only of desert environments, but also of other Mexican ecosystems present in the country.
The distribution of species that were recorded in CCB shows a mixture between cerambycid species with distributional records in United States and Mexico (Bezark 2020). Many of these species have diurnal habits and an affinity for desert environments. This is useful for understanding the distributional patterns and evolutionary history of cerambycid beetles. The ecological factors and historical events from the Altiplano Mexicano are relevant for determining the geographic distribution of insect species from CCB (Álvarez and Ojeda 2019). Additionally, the presence of host plants in these desert ecosystems is fundamental to their existence in these environments (Pinkava 2016).
The CCB is a unique region with different components from Neotropical and Nearctic biogeographic provinces. This makes it an essential crossroads to understand the evolution of several faunal groups (Álvarez and Ojeda 2019). This work represents the first species list of Cerambycidae in a Mexican desert (CCB, Chihuahuan desert) and Coahuila. Cerambycids provide important ecological services for desert ecosystems. They act as pollinators (MacKay et al. 1987), active agents of decomposition and recyclers of organic matter. As ecosystem agents, these beetles are indispensable for the health and permanency of CCB environments.