Rhinolophus borneensis Peters.

Andersen, Knud, 1905, On some Bats of the Genus Rhinolophus, with Remarks on their Mutual Affinities, and Descriptions of Twenty-six new Forms., Proceedings of the Zoological Society of London 2, pp. 75-145 : 84-87

6. Rhinolophus borneensis Peters. (Plate III. fig. 5 a, b, c.)

Diagnosis. Similar to Rh. celebensis , but with broader nasal swellings. Small: forearm 41'2-46'3 mm.

Details. Sella so slightly constricted as to be almost parallelmargined from base to summit; in some individuals the constriction is completely obsolete; height of sella about 3 mm.;

width at base, at middle, and at summit: 2, 1 ’ 8, and 1'7 mm. Lancet almost cuneate, or the lateral margins but slightly concave, never abruptly narrowed at the middle (as in Rh. rouXi ); length of lancet about 4'2 mm. Ears and wings quite as in Rh. celebensis . Plagiopatagium inserted on tarsus, or as much as 1'5 mm. above the tarsal joint.

Colour. There is an extreme dark phase and an extreme red phase, connected by several intermediate stages.

(1) Dark phase. — ♀, Banguey Isl. (Brit. Mus.); two ♂, Pulo Sarutu (Un. St. Nat.-Mus.); all of them full-grown, but with unworn teeth; distal epiphyses of metacarpals in two of them ossified, in one not completely so; in alcohol, unfaded. General impression of upper side: brown. The true colour is a deep brown shade of “ drab ”; base of hairs next to “ broccoli-brown. ” Under side between “ wood-brown ” and “ broccoli-brown.” The individuals are not precisely, but almost, alike in tinge.

(2) Intermediate stage, nearer to “ dark phase. ” — ♂ ad., ♀ ad., Labuan (B.M.); ♂ ad., N.W. Borneo (B. M.); teeth either quite unworn, or almost unworn; distal epiphyses of metacarpals ossified; in alcohol, unfaded. Upper side “russet,” base of hairs but slightly lighter. Under side “ wood-brown. ”

(3) Intermediate stage, nearer to “red phase.”— ♀ ad., Sirhassen (U. N. S. M.); ♂ ad., ♀ ad., Karimata (U. N. S. M.); teeth either quite unworn, or very slightly worn; distal epiphyses of metacarpals ossified; in alcohol, unfaded. Much like the foregoing, but also the under side of the body “ russet. ”

(4) Extreme red phase. — ♂ ad., Sirhassen (B.M.); teeth unworn; epiphyses ossified; in alcohol, unfaded. Much like the extreme red phase of Rh. rouXi : not far from “cadmium orange ” above; “ orange ” beneath.

As proved by the above, these differences in colour are independent of the geographical habitat and of the sex of the individuals, seemingly also of the age. So far as the present material goes, the only “ phase ” in which a quite young, though full-grown, individual occurs (epiphyses not quite ossified) is the dark phase; but it may be accidental: the individual which represents the extreme red phase is, at all events, only a few months older (teeth unworn).

Skull. As in Rh. celebensis , but with broader nasal swellings (5'4 mm., on an average).

Dentition. p3 almost always completely external, but in one skull (out of eleven) half in row. Cingula of p2 and p(in contact (six), or very slightly separated (four), or distinctly separated (one), p2 always in the tooth-row; cusp very small. In four individuals there is an extremely narrow interspace between p2 and p1 (the former place of p3).

Distribution. N. Borneo; S. Natunas; Karimata Group.

Technical name. The type of Rh. borneensis , in the Berlin Museum, is from Labuan. There are two specimens from the

same island in the British Museum *. As, however, 7? A. borneensis

has for many years been completely confused not only with several more or less closely related species, but also with the widely different Rh. minor, the following remarks may not be out of place

here

The salient point in the original description of Rh. borneensis , as given by Prof. Peters (Zoe. infra cit.'), is this: “ Sattel .... an dem vordem obera Ende abgerundet, die hintere, zusammengedrückte Spitze [ï. e. the posterior connecting process] kaum hoher, abgerundet.” I have emphasised the last three words, because they clearly prove that Rh. borneensis belongs to what here is called the. simpleX group (connecting process low and rounded off), and has, nothing to do with Rh. minor or its allies (connecting process projecting and pointed). But ten years later (MB. Akad. Berlin, 1871, p. 306), Peters himself believed Rh. borneensis to be identical with Rh. minor, described by Horsfield so long ago as 1824. The reason was, beyond all doubt, this: to identify Horsfield’s Bats without an examination of the types is, in most cases, impossible; and Peters had not seen the type of Rh. minor (then in the Indian Museum, London, now in the British Museum), but only the bad figure in the ‘ Researches in Java’; as, furthermore, the two species in many respects (size, wings, sella., ears, & c.) are, eXternally, puzzling alike, the mistake is easily explained. Thus, according to Peters, there were two small Indo-Malayan. Rhinolophi: the one, with a low and rounded connecting process,, he called Rh. minor, Horsf. (synonym: Rh. borneensis, Peters ); the other, with a projecting and pointed connecting process, lie identified with Temminck’s Rh. pusillus , stated to be from Java. Under these circumstances, a quite reasonable conclusion: we had a name for either “ species,” and perfectly clear diagnoses. Dobson, who examined the type of Rh. minor, states, quite correctly, that the connecting process is projecting and pointed; when, nevertheless, be put Rh. borneensis down in the list of “ synonyms ” to Rh. minor, he must have overlooked the most important point in Peters’s description of borneensis , the shape of the connecting process. Dobson, therefore, called the small Indo­ Malayan Rhinolophus with pointed process Rh. minor (synonym: Rh. borneensis')'. thus, the names were the same as employed by Peters, but the diagnosis exactly the reverse; Temminck’s Rh. pusillus he identified with Rh. hipposiderus (sic); and as to the small Indo-Malayan Rhinolophus with rounded process (the true borneensis') he put it down under Rh. affinis, Horsf. (!), with which species he also united the very different Rh. rouXi , Temm., at the same time keeping a genuine Rh. rouXi separate as Rh. potersi. This accumulation of errors and wrong identifications

is the true reason of the exceedingly confused state in which this group of Bats has remained, making a safe determination of specimens procured almost impossible.

Geographical races. There seems to be two forms of Rh. borneensis , differing, slightly, in the size of the ears, and in geographical habitat.