Monday, December 18, 2023

[Mammalogy • 2023] Myotis nustraleNewly described and already Endangered: A New mammal Species endemic to Corsica (Chiroptera: Vespertilionidae)


Myotis nustrale Ruedi, Beuneux & Puechmaille, 

in Puechmaille, Dool, Beuneux et Ruedi, 2023. 

Abstract
The Myotis nattereri species complex has been the focus of several recent morphological and molecular surveys to assess the species status of various named forms, including three informally referred to as Myotis sp. A, M. sp. B and M. sp. C. The first two forms have now been formally described as distinct biological species, and named M. crypticus and M. zenatius, respectively, both distinct from the nominotypical M. nattereri s. str. and M. escalerai. The latter form, Myotis sp. C is known only from Corsica. Here we demonstrate that this form has not only unique mitochondrial haplotypes but also several nuclear alleles that are divergent and not found anywhere else, which emphasizes its long independent evolution. We therefore confirm its specific status and describe it as a new species. Its ecology and rupicolous roosting habits resemble those of the Iberian M. escalerai, but it is otherwise morphologically most similar to M. crypticus. This new species is endemic to Corsica and is apparently very rare and essentially localised to mountain forests. Owing to its restricted distribution, its small population size, and limited population connectivity, it seems highly vulnerable to climate change and thus should be classified as endangered.

KEYWORDS: cryptic species, DNA, Myotis, nuclear loci, taxonomy, Vespertilionidae

External characters of Myotis nustrale sp. nov. Panels are close-ups of the female holotype (MNHN-ZM-2023-12), except the lower right one which is a picture from a released adult individual (Photo © Yann Le Bris). The upper left panel illustrates the stiff hairs running along the uropatagium, viewed from below. The upper right panel is the right foot with wing insertion to the base of the outer toe, in ventral view. The lower left panel illustrates the long and straight tragus and unnotched ear of the female holotype. On the portrait of the live individual, notice the black chin spot on the lower lip.

Portraits and hind feet (dorsal view) of an adult female Myotis nustrale sp. nov. caught near Bavella, in southern Corsica (left) and an adult female M. crypticus from the Jura mountains in Switzerland (right). Notice that the latter individual has a faint line bordering the lower lip, while the former has a much more conspicuous chin spot. Wing insertion to the outer toe is, however, identical in both species. For the left individual, the wing was not stretched while it was stretched for the right individual.

Myotis nustrale sp. nov. Ruedi, Beuneux & Puechmaille

Distribution: This species is endemic to the island of Corsica (France), in the Mediterranean Sea (Fig. 1).

Diagnosis: Medium sized Myotis (W 5.5-9.5 g; FA 38.4-41.3 mm) with relatively long, unnotched ears; tragus straight, reaching beyond half the length of the conch (Fig. 5). The long, unkeeled and S-shaped calcar running along the proximal half of the uropatagium, as well as the stiff hairs visible on the trailing edge of the uropatagium are typical features of all taxa in the Myotis nattereri species complex. Stiff hairs of the uropatagium occur in two rows, with only few hairs being reflected backwards (Fig. 5).
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Etymology: The specific epithet nustrale is a pronoun in apposition meaning “ours - le notre” in the Corsican language.


Sébastien J. Puechmaille, Serena Dool, Gregory Beuneux and Manuel Ruedi. 2023. Newly described and already Endangered: A New mammal Species endemic to Corsica. Revue suisse de Zoologie. 130(2); 335-351 (2023). DOI: 10.35929/RSZ.0108

Myotis nattereri représente un complexe d'espèces qui a mobilisé l'attention récente de morphologistes et de généticiens pour définir le statut spécifique de diverses formes, y compris celles informellement connues sous l'appellation de Myotis sp. A, M. sp. B et M. sp. C. Les deux premières formes ont depuis été reconnues comme espèces à part entière et nommées respectivement M. crypticus et M. zenatius; elles diffèrent des espèces nominales M. nattereri au sens strict et M. escalerai. La dernière forme, Myotis sp. C, n'est connue que de Corse. Nous démontrons ici qu'elle possède non seulement des haplotypes mitochondriaux uniques, mais aussi plusieurs allèles nucléaires divergents que l'on ne retrouve nulle part ailleurs et qui démontrent une longue évolution indépendante de ce taxon. Ceci confirme son statut spécifique et nous la décrivons par conséquent comme espèce nouvelle. Son mode de vie et ses affinités rupicoles la rapprochent de l'espèce ibérique M. escalerai, bien que morphologiquement elle soit plus semblable à M. crypticus. Cette nouvelle espèce est endémique de Corse et y est apparemment très rare et presque exclusivement localisée aux régions montagneuses boisées. En raison de sa distribution restreinte, de la petite taille de ses populations, et de la connectivité restreinte de ses populations, elle semble très vulnérable au changement climatique et devrait être classée comme espèce en danger.