Murina hilonghilong, Eger & Sedlock & Lim & Heaney, 2025

Murina hilonghilong sp. nov.

( Figs. 1 View FIGURE 1 , 8A View FIGURE 8 , 9A View FIGURE 9 ; Tables 1, 2A, 2B).

Holotype. FMNH 190118 About FMNH , field number RKSG 82 , adult male, alcohol specimen with skull extracted, collected in a harp trap by R. K. S. Gomez, 30 July 2006. The holotype is currently housed at FMNH but will be transferred to the National Museum of the Philippines, Manila before the end of 2025 where it has been assigned PNM 9674 View Materials . The nucleotide sequence as deposited in Genbank of Cytb mitochondrial gene is PV659272 and DBY nuclear gene is PV659349.

Type locality. Barangay (Brgy.) Adlay, Carrascal Municipality, Surigao del Sur Province, Hilong-hilong Range, Mindanao Is., Philippines (coordinates not recorded in the field, subsequently estimated from topographic maps as 9.088 N, 125.73 E); elevation 85 m.

Paratype. FMNH 191407 About FMNH female, ( RKSG 198 ) collected 17 October 2006 at Brgy San Antonio, Mt Hilonghilong , Agusan del Norte Province, Mindanao Is. Philippines (coordinates not recorded in the field, subsequently estimated from topographic maps as 9.087 N, 125.70 E; elevation 1400 m) GoogleMaps .

Etymology. This species is named after the mountain range where it was captured, Mt. Hilong-hilong, which stretches across two provinces— Agusan del Norte and Surigao del Sur in northeastern Mindanao. We use the name of the mountain as a noun in apposition.

Measurements of holotype. (in mm) and body mass (in g): total length, 91; tail vertebrae, 31; hind foot, 9; ear, 15, forearm, 41; and mass, 10.

Diagnosis. This is the largest species of Murina in the Philippines, and the largest of all species of Murina . Murina hilonghilong has dentition like Murina cyclotis with upper premolars similar in size to each other, with reduced mesostyles on M 1 and M 2 ( Fig. 9A View FIGURE 9 ) and reduced talonids on the lower molars (M 1 and M 2; Fig. 9A View FIGURE 9 ) but is larger in body size and skull size, with a white ventrum and a large difference in Cytb sequence (>17%). The sagittal and lambdoidal crests are well defined.

Description. The dorsal fur is tricoloured, with pale grey bases changing to buff with pale reddish-brown tips; guard hairs also have reddish brown tips. The ventrum is unicoloured white from the throat to the centre of the abdomen. On the sides of the abdomen the hairs are white at the base blending to buff tips. The guard hairs on the belly are long, white, and shiny, more obvious in the mid ventrum than along the sides. The uropatagium is hairy (pale orange) with long hairs covering the proximal half. Likewise, the feet are covered with long hairs extending beyond the claws. The forearm and thumb are also quite hairy, but the hairs are short and pale in colour.

The ears are relatively short with a notch on the posterior border. The tragus is long and typical of Murina species. The calcar is long, and the wing membrane is inserted on the side of the toe at the base of the claw.

The skull is robust with a deep rostrum which has a well-marked rostral depression, and heavy, well developed sagittal and clearly defined lambdoid crests ( Fig. 8A View FIGURE 8 ). The upper toothrows are parallel and the teeth are heavy in appearance. The inner upper incisor is simple in shape with a bicuspidate tip that may not be obvious in a worn tooth, and the tooth is mostly obscured by the larger outer incisor. The upper canine is large and heavy, P 2 and P 4 are similar in shape with P 4 slightly larger than P 2. The first and second upper molars are similar in size and shape with greatly reduced mesostyles. As in other species of Murina , M 3 is greatly reduced. The basisphenoid pits are well defined and tear drop in shape ( Fig. 9A View FIGURE 9 ). On the mandible, the incisors are tricuspidate, and the remaining teeth are heavy in appearance. The canine is short but slightly longer than the premolars in both sexes; P 4 is larger than P 2 and both premolars on the male specimen are worn. M 1 is larger than M 2 and the talonid on M 1 is approximately ¼ the size of the trigonid but on M2 it is closer to 1/3 the size of the trigonid. The male holotype is significantly smaller in skull and external measurements than the female paratype ( PC1 ) and they differ in shape ( PC2 , Fig. 6). The coronoid process is distinctly shorter in the male relative to the female accounting for their difference in shape ( Fig. 6) ( HCP 6.3 mm ( ♂) and 7.6 ( ♀). See Tables 1 and 2A, 2B for selected external and skull measurements.

○ = Female

□ = Male

Ecology. The only two specimens representing this species were captured at 85 m elevation in magkono (ironwood) forest ( Xanthostemon verdugonianus ) and in regenerating transitional lowland-montane forest at 1400 m on Mt. Hilong-hilong, the highest mountain in northeastern Mindanao and a Key Biodiversity Area ( Mallari et al. 2001). Home to endemic birds, mammals, and amphibians ( Plaza & Sanguila 2015, Gracia et al. 2021), Mt. Hilonghilong was identified in 2014 by Bird Life International as an Important Bird and Biodiversity Area in Danger.

Distribution. Currently known only from two localities in NE Mindanao, associated with the Hilong-hilong Mountain Range ( Fig.1 View FIGURE 1 ). They probably occur elsewhere in this area.

Genetic Analyses. Cytochrome b and Dby sequences are available on GenBank for specimens listed in Appendices 2 and 3. Murina hilonghilong is one of three divergent lineages supported by Dby data (one site, Fig. 2 View FIGURE 2 ) from the Philippines that is closely related to M. cyclotis from mainland Asia. Relative divergences among Philippine species are discussed below.