Letheobia, Cope, 1868

Jablonski, Daniel, Khashab, Rami, Rida, Hamza & Sadek, Riyad A., 2024, A snake genus new to the reptile list of Lebanon: Genetic affiliation and distribution of Letheobia simoni (Boettger, 1879), Zootaxa 5543 (1), pp. 145-150 : 147

Our data document the first recorded presence of Letheobia in Lebanon.

This extends the known northernmost distribution of L. simoni in the North Galilee, specifically Nahal Dishon, ZFMK 052243, and “the Jordan Valley, approximately 25 km north of Lake Galilee” ( Sivan & Werner 1992; Franzen 2000; Fig. 1A ), by more than 30 km to the north. This report adds a new genus and species to the list of reptiles in the country and represents the smallest Lebanese snake. However, the presence of this genus in southern Lebanon is not surprising from a biogeographic perspective. There are several (fossorial or semi-fossorial) reptiles that are endemic to the southern Levant that are present or expected in southern Lebanon, following the thermo-Mediterranean and eu-Mediterranean phyto-association zones ( Abi Saleh & Safi 1988). These include Ablepharus rueppellii (Gray, 1839) , Chalcides guentheri Boulenger, 1887 , Ophiomorus latastii Boulenger, 1887 (all Scincidae ), and Micrelaps muelleri Boettger, 1880 (Micrelapidae). Their evolutionary lineages probably arrived in the region before the formation the Saharo-Arabian deserts and now primarily represent West Asian and African elements that have evolved in the southern Levant.

Letheobia simoni is not the only fossorial snake species present in Lebanon. Another species from the same family, Xerotyphlops syriacus (Jan, 1864) , is common and can be misidentified in the field as a Letheobia . This is why the new member of the Lebanese herpetofauna could have gone unnoticed for a long time. In the future, under better political and safety conditions, which affect biodiversity research, further investigations will be needed in southern Lebanon to find new locations of occurrence for the species and to understand the distribution patterns between the genera Xerotyphlops and Letheobia . Field investigations are also necessary to determine the potential presence of another fossorial snake, morphologically similar to the family Typhlopidae but belonging to the family Leptotyphlopidae , Myriopholis macrorhyncha (Jan, 1860) . Although this species has never been recorded in Lebanon, it is known to inhabit surrounding countries with similar environments to those found in southern and eastern parts of the country.

The genetically investigated specimen of L. simoni from Kfar Joz/Kfour forms a different evolutionary lineage in phylogenetic networks ( Fig. 1B,C ) compared to sequences available for the species from Jordan. The average uncorrected p distance between them is high—6.0% for 12S and 1.4% for NT3, suggesting an ancient divergence. Similarly, there are high levels of divergence (1.6%) for NT3 (12S data for L. episcopus is not available) between L. simoni from Lebanon and L. episcopus from southern Turkey (KC848457-8).

Because Haifa, the type locality of L. simoni , is geographically close to the population genetically investigated in this study ( Fig. 1A ), we expect that both populations are conspecific, which has taxonomic implications for the genus in the region. This highlights the need for further phylogeographic investigations, as the diversity of the genus Letheobia in the Levant and the Middle East is likely higher than currently recognized.

Figures

FIGURE 1. (A) Distribution data for Letheobia simoni from Nabatieh and South Lebanon and Galilee and the Hula/Jordan Valley: 1—Kfar Joz/Kfour, 2—Maarake, 3—Nahal Dishon (ZFMK 052243; 33.062°N, 35.526°E), 4—the Jordan Valley, approximately 25 km north of Lake Galilee (Sivan & Werner 1992; 33.123°N, 35.651°E). Other localities are: 5—Bar et al. (2021), 6—https://www.inaturalist.org/observations/190242290, 7—https://www.inaturalist.org/observations/31283396, 8—https://www.inaturalist.org/observations/175493806, 9—Boettger (1879, 1880), 10—Warburg (1978), 11—Franzen (2000), 12—Haas (1951). The orange shading represents the expected range polygon for the species extralimital to South Lebanon. (B, C) Phylogenetic networks (NeighborNet) from concatenated 12S and NT3 dataset (B) and NT3 only (C), including specimen from Lebanon and other congeners. The microhabitat of the species in Nabatieh Governorate (D) and dorsal (E), lateral (F) and ventral (G) views of the head of Letheobia simoni (CUHC 12630) from Kfar Joz/Kfour, Nabatieh Governorate.