Myotis soror, Ruedi, Manuel, Csorba, Gábor, Lin, Liang- Kong & Chou, Cheng-Han, 2015

Ruedi, Manuel, Csorba, Gábor, Lin, Liang- Kong & Chou, Cheng-Han, 2015, Molecular phylogeny and morphological revision of Myotis bats (Chiroptera: Vespertilionidae) from Taiwan and adjacent China, Zootaxa 3920 (1), pp. 301-342 : 327-329

Myotis soror sp. n.

Figures 2, 3, 5 , 8 a, and 9a

Holotype. Adult female collected by G. Csorba, C.-C. Huang and H.-C. Kuo on 5 September 2003 (field number # CSOTA 141). The dry skin and skull are deposited in the collections of the Hungarian Natural History Museum ( HNHM) under accession number 2003.36.20. Part of the mitochondrial Cyt b (413 bp) was sequenced from tissue extracts taken from the holotype; this sequence is deposited in GenBank under accession number KP187901 . The Cyt b gene was used in the phylogenetic analyses presented herein ( Fig. 3).

Type locality. The holotype and only known specimen was caught along the “water pipe road”, near the Highland Experimental Farm of National Taiwan University, Nantou County, Taiwan ROC (approximate coordinates: 24°05’ N, 121°09’ E), at an altitude of 2100 m above sea level (location 9 in figure 1).

Distribution. The only known specimen of M. soror sp. n. is an adult female caught in a mist-net placed across a small road at Meifong, Nantou County, in the slopes of Mt Hehuan, in central Taiwan (location 9 in figure 1). The evergreen, temperate forests surrounding this area is the typical vegetation found at this elevation (2100 m). Other species of bat caught in the same area during our survey include an unknown species of Pipistrellus , Harpiola isodon , M. frater , M. laniger , M. secundus sp. n., S. latirostris , Murina gracilis , Plecotus taivanus , Miniopterus fuliginosus , Barbastella leucomelas , Rhinolophus monoceros and R. formosae . As none of the previous, intensive surveys of the bat fauna of Taiwan evidenced this species elsewhere ( Chou 2004; Lin et al. 2004), M. soror sp. n. might indeed be a very rare forest species. Nothing is known about its natural history besides that the female was in a post-lactating stage (with teats still enlarged and devoid of hairs) when it was collected, and thus must have been breeding recently in the area.

Etymology. We name it soror (meaning sister in Latin) as it is clearly related to Myotis frater , its sister species in phylogenetic reconstructions (see Clade III in figure 3). Owing to its peculiar coloration, we suggest Reddish Myotis as an appropriate vernacular name.

Measurements of the holotype. Measurements are in mm and, unlike in other species, were taken on the prepared specimen. Head and body length, 48; tail length, 41; forearm length, 42.1; hind foot length (including claw), 7.6; tibia length, 17.2; thumb length, 5.1 and claw 2.5; ear length, 11; tragus length, 6; greatest skull length, including incisors, 13.8; greatest zygomatic breadth, 8.9; postorbital breadth, 4.1; mastoid breadth, 7.8; greatest braincase width, 7.2; upper canine-molar toothrow, 5.2; width across upper canines, 4.2; width across 3rd upper molars, 5.7 ( Table 4).

Diagnosis. Medium-sized Myotis with striking pelage color, rich cinnamon-brown with lighter, golden hair tips dorsally ( Fig. 7 a) and only slightly lighter ventrally. Color of face brownish and other bare parts dark brown.

Wing membranes attached close to base of outer toe, on the distal part of the metatarsus ( Fig. 7 b). Feet nearly half tibia length. Tail notably shorter than head and body length. Ears relatively short and broad with a distinct notch on the middle of the rear edge of conch ( Fig. 7 c). The inner and outer sides of the conch are covered with sparse, cinnamon-rufous hairs. Skull angular, with short rostrum and abruptly raised frontal part of braincase (as seen in profile, Fig. 8 a). Teeth relatively robust with second upper premolars small and moderately displaced inside from toothrow, but not visible in side view. Upper canines strong, with a marked groove along the labial edge.

Description. The pelage is dense, soft and relatively long on the dorsum (about 6 mm); dorsal hairs cinnamon brown on the base and becoming progressively lighter towards the tips, the last 2 mm being golden yellow, giving a frosted appearance to the dorsal fur. Ventral parts appear slightly paler, with hairs brown to the middle, becoming lighter, almost creamy towards the tip. Bare parts, including ears and patagium, reddish-brown, with face lighter, flesh colored. Ears short and broad, not reaching the nose tip when laid forward; conspicuous notch at two-thirds of its height on the rear edge ( Fig. 7 c). Long (up to 1.6 mm), sparse cinnamon hairs are present on both inner and outer sides of the conch. Tragus relatively short, but reaching the ear notch; the anterior edge is slightly convex but the exterior margin has a small lobe at the base (hidden into the conch), and a larger one along half of its length; the tragus is convergent and tapers medially forming a slightly rounded head at the tip ( Fig. 7 c). Wing membranes are essentially naked (except the underparts, close to the body), and attached to the distal parts of the metacarpus, near the base of the outer toe ( Fig. 7 b). Feet are robust, with strong curved claws, and about half the size of tibia length. Uropatagium broad with tail almost fully included in the membrane. The calcar is short (about one-third uropatagium edge length), and bears an indistinct, unkeeled lobe. The tail is notably shorter than head and body length.

When viewed in profile, the skull has a relatively short rostrum, and an abruptly raising frontal part of the braincase ( Fig. 9 a). The occipital part looks like a square in profile or when viewed from above ( Fig. 8 a). Lambdoid crests are visible laterally, but no notable sagittal crest is present.

Dental formula I 2 /3 C 1/1 PM 3/3 M 3/3, comprising the adult dentition of 38 teeth. Teeth are robust, with upper canines longer than third premolars, but the lower canines are much weaker, barely reaching the height of lower premolars ( Fig. 8 a). The two upper incisive are nearly as high as wide, short, of comparable size and both are visible in side view. The upper canines have a distinct groove along the labial edge. The first upper premolar is small and aligned in toothrow, but the second is minute and displaced inwards and barely visible in side view. The third premolar is large, but bears an inconspicuous paraconule in its front margin. Molars are robust, but low, with ill-defined paraconules. The three lower premolars are in a row, not particularly crowded. All lower molars are myotodont.

Comparisons. Owing to its short rostrum, raised frontal parts of braincase, angular skull shape ( Figs. 8 a, 9a) and inwards displaced second upper premolars, Myotis soror sp. n. is clearly related to the M. frater species complex (sensu Tsytsulina & Strelkov 2001). However, it differs genetically from sympatric specimens of M. frater by at least 11 % (K2P divergence at the Cyt b gene; Table 5 ). Its rich cinnamon pelage ( Fig. 7 a) with golden frosted appearance of the dorsal fur is also unique in this group, all other taxa living in temperate regions being darker brown (sometimes lighter brown in juvenile specimens, Yoshiyuki 1989). The desert form M. bucharensis is decidedly much paler and slightly larger. With a forearm length of 42.1 mm, M. soror sp. n. is also larger than the Far Eastern taxa ( longicaudatus , kaguyae and eniseensis) and slightly larger than sympatric M. frater s. s. (FA barely reaching 41 mm; Table 4). The tail of M. soror sp. n. is shorter than head and body length, and thus is considerably shorter than in other taxa in this group ( Table 4). Compared to M. frater s.s. the shape and pilosity of ears differ notably, the notch on the rear edge being less visible in the later species, with pilosity confined to inner side (hairy on both sides in M. soror sp. n., Fig. 7 c). Due to an absolute shorter tibia length (about 17 mm) compared to other taxa in the frater s. l. group (about 20 mm or more), the feet (about 8 mm) appear relatively large, almost half the tibia length, whereas they are much shorter than 50% tibia length in the other related taxa. Other, unrelated Asian species of Myotis with inwards displaced second upper premolars, such as M. davidii , are either much smaller (FA about 31 mm) and have a darker, blackish pelage color, or are much larger (FA about 50 mm) and have particolored wings (see M. formosus s.l. group, Csorba et al. 2014).

Phylogenetic relationships. The partial (413 bp) Cyt b gene of the holotype of M. soror sp. n. diverges by at least 11% K2P distance from any other homologous sequences, including from its sympatric, sister taxon M. f. frater ( Fig. 2; Table 5 ).

Figures

FIGURE 5. Skulls of (a) Myotis laniger from Fujian, China (ZMB 4146, lectotype; hind parts missing), and (b) M. laniger from Taiwan (THUMB 103). Scale = 5 mm.

FIGURE 7. Myotis soror sp. n. (HNHM 2003.36. 20, holotype). (a) Dry study skin (b) attachment point of the wing membrane, and (c) close-up of the notched ear and tragus of the live specimen.

FIGURE 8. Lateral and dorsal views of skull, and mandible of (a) Myotis soror sp. n. (HNHM 2003.36. 20., holotype), (b) M. frater (TESRI B 0283), (c) M. formosus (THUMB 65), and (d) M. rufoniger (THUMB 30022). All specimens are from Taiwan. Scale = 10 mm.

FIGURE 9. Skulls of (a) M. soror sp. n. (HNHM 2003.36. 20, holotype), (b) Myotis frater from Fujian, China (AMNH 48029, holotype), and (c) M. frater from Taiwan (HNHM 2004.19.3). Scale = 5 mm.