Rhinolophus rouxii, Temminck, 1835

Burgin, Connor, 2019, Rhinolophidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 280-332 : 325

92 . Indian Rufous Horseshoe Bat

Rhinolophus rouxii

French: Rhinolophe de Roux / German: Rotbraune Indien-Hufeisennase / Spanish: Herradura de Roux

Other common names: Rufous Horseshoe Bat

Taxonomy. Rhinolophus rouxii Temminck, 1835 ,

“ continent de 1’ India... Pondichéry [= Puducherry] et à Calcutta .” Rhinolophus rouxii is sister to a clade that includes R.sinicus and R. thomasi ; all these species belong to the rouxii species group. The rouxii group may be close to the euryotis species group, but more detailed studies are needed to clarify its relationships with congeners. A sympatrically distributed form from the southern Western Ghats of India, with a higher (c.92 kHz) echolocation frequency, was recently named “ R indorouxii ;” however, the paper in which the name was introduced did not provide a proper description, type specimen, or type locality, so the name is a nomen nudum. This form is here included in R rouxii , but it may represent a distinct species, based on limited genetic, morphological, and echolocation data presented by B. Chattopadhyay and colleagues in 2012. More substantial morphological and genetic evidence is needed, using specimens from throughout the distribution of R rouxii , to support its species status (along with a properly introduced name). There appears to be some ambiguity regarding the distribution of this species and R sinicus in published records. North Indian records that were previously attributed to R rouxii are now considered to refer to R. sinicus , although the record from south-central Myanmar reported here is still considered R.rouxii . Two subspecies recognized.

Subspecies and Distribution.

R. r. rouxii Temminck, 1835 — W, E & S India (Maharashtra, Goa , Karnataka, Kerala, Tamil Nadu, Puducherry, Andhra Pradesh, Chhattisgarh, Odisha, and West Bengal) and S Myanmar; possibly also in S China (Yunnan).

R.r. rubidus Kelaart, 1850 - Sri Lanka.

Descriptive notes. Head—body 42—66 mm, tail 20- 5—33 mm, ear 14- 5—22 mm, hindfoot 7-2—12- 8 mm, forearm 44-4—52- 3 mm; weight 12-2—14- 8 g. The Indian Rufous Horseshoe Bat. It has distinct winter and summer pelage: summer (May—September) pelage is dull brown to grayish brown dorsally (hairs with drab base), with wood brown to light drab ventral pelage; winter (October—April) pelage is bright orange rufous dorsally and ventrally; intermediate forms are known. Ears are small. Noseleaf has hastate lancet that abruptly narrows in middle and is fairly variable in height; connecting process is rounded, but rounded portion does not start at tip of sella, as in euryotis species group; sella is virtually parallel-sided, occasionally with slight middle constriction, and has broadly rounded tip; horseshoe is narrow in relation to muzzle (7-9- 2 mm wide) and small lateral leaflets are usually present. Lower lip has three mental grooves. Baculum is heavily built (mean of 2-3 mm long) with simple shaft that curves ventrally at rounded tip; basal portion is slightly flattened dorso-ventrally and there is simple ventral emargination that is wider and deeper than dorsal one; tip widens laterally and is rather flat dorso-ventrally, and shaft is somewhat higher than wide. Skull is robust (zygomatic width always much wider than mastoid width); anterior median swellings are small and low; posterior swellings are wide; sagittal crest is strongly or moderately developed; frontal depression is shallow; supraorbital crests are conspicuous but not especially sharp. C1 is long and massive; P2 is moderate in size and either within tooth row or occasionally halfway external to it; C1 is more slender than C1; P3 is partly or completely extruded from tooth row, rarely missing; P2 and P4 are usually separate but sometimes in contact. Dental formula is the typical of 32 teeth for the genus or 30 when a lower premolar is missing. Chromosomal complement has 2n = 56 and FNa = 60 (FN = 62 in India).

Habitat. Typically a forest-dwelling species, the Indian Rufous Horseshoe Bat can be found in moist evergreen and lowland forests. Recorded at elevations from sea level up to 1370 m.

Food and Feeding. Indian Rufous Horseshoe Bats forage by aerial-hawking and flycatching. While foraging, they fly low below the canopy and they tend to fly through areas cluttered with vegetation in the process. It is also suggested that the species may fly higher in the canopy when trees are blooming to capture insects that are attracted to the flowers. In Sri Lanka, each bat foraged over an area of c. 400 m 2 and would exhibit perch-hunting, making short outings to capture prey and come back to eat it. Diet seems to vary, but the species probably feeds mainly on grasshoppers, moths, beetles, termites, mosquitoes, and other flies.

Breeding. There is a well-defined single breeding season; copulation takes place in the last week of December in Maharashtra and probably months later in Sri Lanka. Large maternity colonies are subsequently formed, composed only of adult females until young are bom. Early development after fertilization is slow and there is delayed implantation of the blastocyst. The fetus is generally carried in the right horn of the uterus. Gestation lasts 150—160 days, births occurring in the last week of May or in earlyJune in southern India, and apparently in October in Sri Lanka. Newborn young weigh 1-8—2- 1 g; there appears to be a skewed birth sex-ratio, with males outnumbering females (this may indicate that males have a higher mortality rate). Young are bom deaf and remain so for the first week (typical of Rhinolophidae , unlike in Hipposideridae ), and as they develop their hearing, they also develop their echolocation calls. They first begin to call in their second or third week of life, and their echolocation frequency gradually increases from 53-7—65-7 kHz in the second and third week to 72-4-77-2 kHz in the fifth week, for the second harmonic. This is attributed to the development and fine tuning of the auditory fovea, which develops by the third week. Young are weaned around the first week of August in southern India.

Activity patterns. Indian Rufous Horseshoe Bats roost by day in caves, tunnels, tree hollows, unused wells, temples, and rarely other old buildings such as houses and bams; they prefer humid areas. They leave the day roost to forage immediately after sunset in Sri Lanka, foraging by aerial-hawking for the first 30—60 minutes of the night, which is followed by a 1-2-hour resting period. After this rest break, individuals forage through the rest of the night by fly-catching. Calls are shaped FM/CF/FM, with a peak GF of 77-9-84-7 kHz in southern India and 73-79 kHz in Sri Lanka. The proposed new species from the southern Western Ghats of India (named “ indorouxii but invalidly) has a peak F of87-2-94 kHz (mean 92-1 kHz) and durations of 2-2-65-3 milliseconds (mean 24-4 milliseconds), and in an earlier study had 92-9-95-4 kHz (mean 94-94-1 kHz). Many detailed studies have been published on the optical and auditory mechanisms and development as well as sound production of this species in India and Sri Lanka; they are too complex to summarize in the present work, but are referenced in the bibliography.

Movements, Home range and Social organization. Indian Rufous Horseshoe Bats roost in large colonies often of several hundred individuals, although they can be found in smaller colonies ofjust a few. During the breeding season, females form large maternity colonies of several hundred while males roost alone or in small groups.

Status and Conservation. Classified as Least Concern on The IUCNRed List, the form proposed as “ Rhinolophus indorouxii " has been assessed as a separate species and classified as Data Deficient. The Indian Rufous Horseshoe Bat is rather widespread and is common throughout much of its distribution in India. It is rare in Myanmar; it may occur in China, where it would probably also be rare. A general population decline is being noticed, although this is not substantial enough to cause recategorization as threatened. The main threats to this species are roost disturbance through cave tourism, and general habitat loss from logging and agricultural expansion.

Bibliography. Andersen (1917), Bates & Harrison (1997), Bates,Thi Mar-Mar eta /. (2004), Behrend & Schuller (2000), Behrend et al. (1999), Bhiwgade (1976,1977), Casseday eta/. (1988), Chattopadhyay, Garg eta/. (2012), Chattopadhyay, Schuller et al. (2010), Corbet & Hill (1992), Csorba eta /. (2003), Eckrich & Neuweiler (1988), Feng & Vater (1985), Firzlaff & Schuller (2001, 2004), Gopalakrishna & Bhiwgade (1974), Gopalakrishna & Ramakrishna (1977), Henson & Rübsamen (1996), Henson eta/. (1985), Kemmer & Vater (2001a, 2001b), Kleiser & Schuller (1995), Kössl (1994a, 1994b), Kuhn & Vater (1995,1996), Leonard eta/. (2004), Melzer (1985), Metzner & Radtke-Schuller (1987), Molur eta/. (2002), Naidu (1985), Neumann & Schuller (1991), Neuweiler eta/. (1987), Pietsch & Schuller (1987), Radtke-Schuller (2001, 2004), Radtke-Schuller et al. (2004), Ramakrishna & Rao (1977), Reimer (1987, 1989, 1991), Roverud (1988), Rübsamen (1987), Rübsamen & Betz (1986), Rübsamen & Schäfer (1990), Schuller, O'Neill & Radtke-Schuller (1991), Schuller, Radtke-Schuller & O'Neill (1988), Schweizer et al. (1981), Sinha (1973), Smith & Xie Yan (2008), Sun Xinde et al. (1993), Thomas (2000), Vanderelst et al.

(2011), Vater (1988), Zhang Lin et al. (2018), Zima eta/. (1992).

Figures

On following pages: 94. Thomas's Horseshoe Bat (Rhinolophus thomasi); 95. Lesser Horseshoe Bat (Rhinolophus hipposideros); 96. rancis's Woolly Horseshoe Bat (Rhinolophus trancisi); 97. Lesser Woolly Horseshoe Bat (Rhinolophus sedulus); 98. Trefoil Horseshoe Bat (Rhinolophus trifoliatus); 99. Northern Woolly Horseshoe Bat (Rhinolophus perniger); 100. Selangor Woolly Horseshoe Bat (Rhinolophus luctoides); 101. Malaysian Woolly Horseshoe Bat (Rhinolophus mono); 102. Great Woolly Horseshoe Bat (Rhinolophus luctus); 1.03. Beddome's Woolly Horseshoe Bat (Rhinolophus beddomei); 104. Formosan Woolly Horseshoe Bat (Rhinolophus formosaë); 105. Thailand Horseshoe Bat (Rhinolophus thailandensis); 106. Dobson's Horseshoe Bat (Rhinolophus yunanensis); 107. Chiew Kwee's Horseshoe Bat (Rhinolophus chiewkweeae); 108. Pearson's Horseshoe Bat (Rhinolophus pearsonii); 109. Mitred Horseshoe Bat (Rhinolophus mitratus).

Subspecies and Distribution. R. r. rouxii Temminck, 1835 — W, E & S India (Maharashtra, Goa , Karnataka, Kerala, Tamil Nadu, Puducherry, Andhra Pradesh, Chhattisgarh, Odisha, and West Bengal) and S Myanmar ; possibly also in S China (Yunnan). R.r. rubidus Kelaart, 1850 - Sri Lanka .