Rhinolophus simplex, Andersen, 1905

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 : 116-120

General Remarks on the Rhinolophus simplex (Group.

The place of origin.— Of all the existing forms, the Australian Rh. megaphyllus is one of the most primitive in dentition. But it is very unlikely that the Australian Continent has been the place of origin of the group. Rh. megaphyllus is the only Australian species of the whole genus; this might suggest the assumption that it is an immigrant into the country, rather than an ancient inhabitant: secondly, Australia is the extreme eastern border for the group (as well as for the genus), no species being known from the islands to the east of the Continent; it would probably not be so, if Australia had been a centre of dispersal for the group: thirdly, megaphyllus has at least two characters which certainly are not primitive—the large nose-leaves, and (probably as a consequence of that) the rather broad nasal swellings: fourthly, megaphyllus looks extremely like an enlarged, continental representative of the Lombok species, Rh. simpleX (just as Rh. rouXi is the larger, continental representative of Rh. borneensis ). These arguments seem to support the conjecture that, not the Australian Continent, but the “ Indo­ Australian Transitional Tract, ” now broken up into numerous larger and smaller islands, and still inhabited by such very primitive forms as simpleX , truncatus, nanus , celebensis , and borneensis , has been the centre from which the group spread eastwards and westwards.

Differentiation t. — The ancestral species seems to have divided into two branches, an eastern and a western. In the eastern, more primitive branch the sagittal crest does not reach quite so far forwards as a point corresponding to the middle of the orbit; in the western the temporal fossa is comparatively a little wider, and the sagittal crest produced forwards more or less beyond that point. The geographical line separating the two branches coincides with the line separating the “ Austro-Malayan ” from the “ Indo-Malayan ” subregion (Celebes being a part of the latter). The eastern branch is, as yet, represented by four known species- Rh. simpleX , megaphyllus , truncatus, and nanus . The western by all the others.

The further evolution, from borneensis to ferrum-equinum , has been discussed above, and is summed up, in the briefest possible form, in the subjoined diagram (p. 120). But the sketch of this group would be deprived of some of its most instructive features if the Ethiopian species were left quite out of consideration. They belong to three closely related types:—

(1) Ethiopian species of the borneensis-stheno-rouxi type.— Far south in Africa, in Bechuanaland and Mashonaland, we find two small species, Rh. denti and simulator , described quite recently They are the Ethiopian representatives of the borneensis type: the same general shape of the skull; essentially the same dentition; the same parallel-margined sella, with a faint or almost imperceptible constriction at the middle; the same style of connecting process; the same proportionate length of the fourth and fifth metacarpals; even the same length of the tail, &c. But there are, in these species, three characters of especial interest, because they enable us to determine still more precisely their phylogenetic place: the nasal swellings (side view) are more projecting than in borneensis , but less than in stheno ; III.2 is lengthened, and IV.1 somewhat shortened, as in this species, — proving that they have originated from a Bat which had already traversed a part of the distance separating borneensis and stheno . The dentition is on a slightly higher level than in borneensis and stheno , the only difference being that p2, although still in the tooth-row (as in the Oriental species), shows a distinct tendency torvards the external side.-

In the extreme south of Africa (Cape Colony) we find a species,. Rh. capensis , which, quite superficially, looks like an enlarged Rh. simulator . It is an African representative of Rh. rouXi : the skull is to such a degree that of rouXi that it would be hard to find any tangible difference, even the measurements being practically the same (on an average smaller than in rouXi ); the nose-leaves (sella, process, lancet) are the same; proportionate length of fourth and fifth metacarpals, of tail and tibia, the same. But the dentition is somewhat more advanced: p2 is generally external, but still, very often, a quite distinct interspace between the canine and p1 indicates its former place; III.2 is somewhat lengthened. In short: Rh. capensis is a “ Rh. rouXi " which in the wing-structure has taken a course towards, in the dentition very slightly beyond, the affinis-stage.

(2) Ethiopinan species of the affinis-type. — On the coasts of the Red Sea we find a species, Rh. clivosus , first made known by Cretzschmar from Mollila in Arabia; I have seen examples from ANDERSEN

the African coast of the Gulf of Aden. It is the closest eXisting relative of the Himalayan Rh. affinis : the same shape of the skull; the same shape of the sella, of the connecting process, of the ears; the same structure of the wings (also the same lengthening of III.’); the same proportionate length of the tail. But it is more advanced in dentition: p3 is not only external (as in affinis'), but very often lost; p2, which in affinis is still in the tooth-row, is in clivosus external and very small. In short: Rh. clivosus is a 11 Rh. affinis ” with ferrum-equinum dentition.

The clivosus type has found its way very far into the Ethiopian Region. Rh. clarlingi *, from Mazoe to Angola, is a modification of this type (as proved by the skull), differing from clivosus in the more pronouncedly pandurate sella, the much broader horse-shoe, the much smaller ears, and, by far the most interesting, in the shortening of the third metacarpal. This last peculiarity is the same as that pointed out above, under Rh. ferrumm equinum: in the wing-structure Rh. darlingi differs from Rh. clivosus quite in the same way as Rh. ferrum-equinum from Rh. affinis . It is a suggestive fact to find this peculiarity so exactly copied by the South-African species.

Rh. acrotis f from Egypt and Erythrea, is, externally, very similar to Rh. clivosus ; also the wing-structure is the same. But the tendency, in clivosus , towards an obliteration of p3 and p2 has been further developed by acrotis : it has completely lost both of these teeth, thus being, in this particular respect, the highest member of the whole group. Rh. acrotis is a “ Rh. affinis ” with a dentition still more advanced than in ferrum-equinum regulus.

(3) Ethiopian species of the ferrum-equinum type.— Rh. augur + is widely distributed, in several geographical races, over the southern part of the Ethiopian Region: the Orange River tract, Natal, the Lower Zambesi. It is the closest eXisting relative of Rh. ferrum-equinum ; the skull, the nose-leaves, the wing-structure are the same; but the dentition is a trifle less advanced, and the ears are smaller.

We find the ferrum-equinum type also further northwards in Tropical Africa (Mombasa): Rh. cleckeni; the skull and dentition, and all external characters of any importance, are as in augu /r; but the horse-shoe is broader.

The area occupied by these two Ethiopian representatives of the /errwn-eg'mmww type extends, broadly speaking, from the Orange River to Mombasa. It is completely cut off from any other region inhabited by that type of Bat; it forms a large enclave bordered to the north and w’est by vast tracts where no representative of ferrum-equinum occui’s; wTe must go so far away from South and Equatorial Africa as the Euphrates Valley, Syria, and Algeria before meeting with the closest relatives of those Ethiopian species. Thus the question suggests itself, by which way the ferrum-equinum type reached Tropical Africa, and why its range there is now so peculiarly insulate. When

THE

trying to answer this question, the following facts must be borne in mind: — Firstly, that all palaeontological evidence is wanting, which detracts from what we know about the affinities and distribution of the now existing representatives of these Bats. Secondly, that the ferrum-equinum type is unknown in Egypt, as well as in the whole region of the continent north of British East Africa, and that we have no reason, of any kind, to believe that it ever existed there. Thirdly, that we have to account not only for the distribution of 7? A. augur and deckeni as compared with the other members of the same section of the genus, but also for the presence in Tropical Africa of representatives of the borneensis and rouXi types, and, be it noticed, representatives which, without exception, are more highly differentiated than their Oriental allies. These facts, so far as tliey go, seem to allow of no other satisfactory explanation than this: the immigration of these Bats, as of so many other Oriental types in the Ethiopian fauna, has taken place by way of the broad tract of land which, as commonly supposed, in a geologically late period connected Southern Asia with the African continent. In the case of the ferrum-equinum type tins explanation would make it evident, why it, though vastly distributed in South and Equatorial Africa, is absent from the whole north of the continent with the exception of the extreme north-western (Mediterranean) coast-region, which it, no doubt, has reached from South-western Europe, since the Algerian race is subspecifically indistinguishable from the Spanish form (h. f. obscurus). In the case of the borneensis and rouXi types it would account for the fact that they are common to the Oriental and Ethiopian Regions, but absent from the whole of the Palaearctic Region. And it would also account for the presence of the genus Rhinolophus in the Ethiopian Region, for, as I shall have to show later on in this paper, all the Ethiopian representatives of the genus are undoubtedly of Oriental origin.

Such being the case, I am able to draw up the following rough sketch of the history of Rh. augur , deckeni, and their Oriental and Palaearctic relatives

The ferrum-equinum type has originated somewhere in South Asia; we find there the long series of more primitive forms which lead up to that type, whereas in the whole of the Ethiopian Region there is not any species with which it can be brought in genetic connection. The ancestral 11 ferrum-equinum ” broke up into three branches: a south-western, a western, and an eastern. The south-western branch, which had spread directly from South Asia into the Ethiopian Region, was cut off from the main stem by the submergence of the connecting tract of land, and is now differentiated into two species—the southern Rh. augur and the northern A / i. deckeni. Both of them have retained at least two “ ancient ” characters: a slightly more primitive dentition (the upper canine and p4 often more or less separated; p2 sometimes half in row *) and a short tail. To the external difference between these two Ethiopian species, viz. a broad horse-shoe in deckeni and a narrow one in augur , we have a parallel ferrum- equinum: a broad horse-shoe in nippon and tragatus , a narrow one in the other races. The western branch spread over South and Central Europe: the dentition slightly more advanced, the tail lengthened. The third branch is now represented by what I have called the Eastern races of ferrum-equinum ; all of them have retained the short tail; nippon (which, so far as the dentition is concerned, has remained on a relatively less advanced stage) leads through tragatus to regulus, in which the dentition has reached the highest stage of development found in any race of

ferrum-equinum.u.