 Reference Base  Contribution to the knowledge of the fossil mammalian fau... |
|
Maarel, F.H. van der, 1932. Contribution to the knowledge of the fossil mammalian fauna of Java. Wetenschappelijke Mededelingen van den Dienst Mijnbouw 15: 1-208, pls. 1-20, tables A-Z
|
|
|
|
| |
| Location: |
World |
| Subject: |
Taxonomy - Evolution |
| Species: |
Fossil |
 |
|
comparison with living Rhinoceros sondaicus - not different
Rhinoceros sondaicus Desmarest fossilis.
Rhinoceros sp., G. Busk, Proc. Zool. Soc. London, 1869, P. 409, text figs. 1-4.
? Rhinoceros sondaicus Cuv. in: R. Lydekker, Cat.Foss.Mamm. in the Br. Mus. part III, 1886, p. 129.
Busk described and figured a left and right fossilized M? of rhinoceros belonging to a species ?not distinguishable by its dental characters from R. sondaicus.' They were obtained from Sarawak, Borneo. Exact locality unknown. Lydekker prosionally referred to R. sondaicus two M1 or M? of opposite sides, and three lower cheekteeth, from a depth of sixty feet in a cavern deposit at Sarawak. The upper molars were said to present all the characters of those of R. sondaicus.
Rhinoceros sondaicus Desmarest
Rhinoceros sondaicus, Desmarest, Mammalogie, 1822, p. 399
Rhinoceros javanicus, F. Cuvier, Hist. nat. des Mammif?res, III, liv. 45, 1824, p.2.
Of this recent species the present writer was able to examine and measure thirteen crania of adult and old individuals, being in all thirteen specimens the M3 (upper) to a smaller or greater extent abraded by wear. The Leiden Museum contained 5 specimens, the Museum of Natura Artis Magistra 6, and the Zoological Institute of Utrecht has 2.
In one specimen (no. 10 of table K), the lower jaw could not be removed without demolishing the specimen. That is the reason why length and breadth of the cheekteeth of this specimen have not been given in table N. In cranium no. 4 only left M2 (upper) and M3 (upper) were present. Cranium no. 6 wanted left P1-M2 (upper). Furthermore from table N will be noticed that in four specimens P1 (upper) of either side is absent. In nearly all cases, there are, however, clear indications that this loss has taken place after the death of the animal.
Before proceeding with a discussion of the individual variation which exists both in cranium, and permanent upper cheekteeth dentition, it will be desirable to call attention to the various tables of measurements.
Table K contains, besides the measurements of the thirteen crania, already mentioned, those of:
1. one cranium of R. sondaicus, borrowed from Franz Toula, Das Nashorn von Hundsheim, Abh. K. K. Geol. Reichsanstalt, XIX, I902, table; [At the time that Toula measured the specimen, it was prserved in the Nat.Mus. of Nat.Hist. of leiden. Apparently it has been exchanged later on.]
2. two crania of the same species, borrowed from Cuvier, Recherches sur les ossemcnts fossiles, 1822, P. 37;
3. one cranium of R. sivalensis, derived from Baker and Durand, 1836, P. 502;
4. one cranium of R. sivasondaiciis, derived from Stremme, 1911, p. 90, 94
5. the two fossil specimens of our own collection.
As to the measurements themselves we followed for the greater part Stremme who in his turn partly joined Toula.
In table L all the values are expressed in % of measurement 13. The total length of the cranium could not be used as unit, because of three crania the total length unknown. Maxima and minima have been printed for R. sondaicus.
Table M contains a number of relations of certain measurements. As to the choice of the measurements we follow Stremme as far as possible. For R. sondaicus, the greatest and smallest number of each horizontal row have been heavy printed.
In table N the length, breadth (both measured at the base of the crown) and the relation length to breadth of each cheektooth have been united. Why this table does not contain - in contradiction to Stremme's table - measurements of premolars and molars of R. sivalensis will be clear, I believe, after what has been stated in the foregoing part. Originally we added to table N also the measurements of two cheekteeth sets which will be found mentioned on P. 39 of Cuvier's paper quoted. When it appeared, however, that in P2-M2 (upper) of one of these rows the relation length / breadth not inconsiderably exceeded the highest value found in the corresponding teeth of twelve foregoing crania it was thought better to exclude them from our table.
As will be seen we have given all dental measurements in mm. Stremme, however, in tenths of mm. In my opinion this is absolutely superfluous. For, though the structure ot a rhinoceros tooth certainly permits exact measuring of the breadth, it surely does not allow of measuring the exact length of the tooth. Moreover it must not be forgotten that length as well as breadth of corresponding teeth of opposite sides may differ distinctly.
In table O, at last, the breadth and length have been expressed in % of resp. the breadth and length of the fourth premolar. Both in table N and O maxima and minima found for the teeth of R. sondaicus have been heavy printed.
We shall now return to the measurements of the sixteen crania of Rhinoceros sondaicus. Both from table L and M it will be seen that even such a relatively small number of specimens already may show a considerable individual variation. Especially concerning some points there appears to exist noticeable differences between the crania of the present species. In this respect we may bring forward:
a. The great differences in degree of depression of the frontal region; smallest in cranium 5 (text fig. 7), greatest in cranium 8 (text fig. 8). Both text figures show, moreover, clearly that a feeble frontal depression coincides with slightly curved nasals. Table L exhibits, furthermore, decidedly that whereas the difference between the greatest and smallest value, found for m.6 in 16 crania of R. sondaicus is 18 %, the greatest value is exceeded by no less than 22 % by the only cranium of R. sivalensis.
b. The considerab;le difference in breadth of the frontal, narrowest in cranium no.2 (text-fig.9), widest in cranium no.1 (Text-fig.10). The specimen of R. sivalensis appears to have a still broader forehead than the specimen of R. sondaicus drawn in text-fig.10.
c. The surprising variability in development and distance between the cristae fronto-parietales.
d. The distinct differences in shape of the occiput; broad and therefore relatively low in cranium 13 (text fig. 11), narrow and comparatively high in cranium 3 (text fig. 12).
Notwithstanding the considerable, individual variation in these 16 crania of R. sondaicus, their measurements show in general decidedly that the specimen of R. sivalensis of table L must be specifically distinct.
As to the individual variation of the dental measurements I may refer to table N and O. Of the structure of the premolars and molars of the recent species we may give the following summary.
P1 (upper) rather small, but not deciduous. Deuterocone of P2 (upper) more or less isolated. P3 Upper) in general entirely molarized; top of deuterocone very seldom free. Deuterocone and tetartocone rather closely approximated in all the P, especially near the base of the crown, so that union takes place after prolonged wear. Postfossette distinctly more shallow than medisinus; consequently very worn teeth only present one pit, namely the buccal part of the medisinus. Crochet generally well developed, occasionally double. No antecrochet. As a rule no crista and medifossette. The crochet is well defined, towards the base it becomes more blunt. Ectoloph with distinct parastyle (protostyle), paracone (protocone) fold, and paracone (protocone) style.
In M2 (upper) and M3 (upper) metastyle. Outer cingulum always absent; inner cingulum either absent in the molars or sometimes represented by a small tubercle at the entrance to the medisinus. Inner cingulum may also be absent in the P; it is, however, mostly present in the form of a very fine row of incipient tubercles. Seldom this row surrounds the whole of the internal side. Sometimes a short row of tubercles is situated in the vicinity of the entrance to the medisinus, in other cases it is attached to the tetartocone, more often, however, to the deuterocone. Anterior and posterior cingulum either smooth or finely crenulatcd. In M3 (upper) posterior cingulum generally represented by a distinct tubercle at the postero-external of the crown. An incipient secondary enamel fold in the postfossette of the premolars may occasionally occur.
Lastly I will bring to the attention the following noticeable peculiarity. The right P3 (upper) of cranium no. 2 appeared to be in the possession of a well developed crista which had regularly united with the crochet, forming a medi-fossette. It is remarkable that none of the other teeth of the cranium in question show any trace of a crista. By the kindness qf the director of the Nat. Mus.of Nat. Hist., Prof. Dr. E.D. Van Oort, I am enabled to give in text fig. 14 an upper view of the specimen, made after a photograph, taken for me in Leyden.
After having dealt with cranium and cheekteeth of R. sondaicus so extensively, we shall try to answer the question: Is the form which Stremme described under the name of R. sivasondaicus, in reality specifically distinct from R. sondaicus, or will it be possible to identify Stremme's species with the help of the more ample materials of the latter we had at our disposal?
After a detailed comparison of the fossil cranium of his collection with that of an old male and a young female of R. sondaicus, Stremme concluded: ?Although the general shape of the skull only shows characteristics which could be within the individual variation, there are differences in the dentition, which seem to justify the recognition of a new species.' (p.91). My own tables L and M show that the correctness of Stremme's first supposition is entirely proved by the facts. The differences in the dentition which Stremme noticed are:
1. Equally worn cheekteeth of the recent species revealed ?a somewhat longer, lightly depressed anterior groove [prefossette] and a sharper, in some teeth divided, sporn.' (p.91).
2. ?The first premolarwhich in all recent Javan rhinos was a small and abraded tooth even in younger animals, is here in the fossil rhinoceros still relatively well preserved in an adult specimen and shows two clear grooves.'
3. When length and breadth of the cheekteeth of Stremme's form and those of R. sondaicus were expressed in % of resp. length and breadth of P4 (upper), it was shown that Stremme's form gave on the whole greater values.
Concerning the presumed first and second difference, I am convinced they will be invalidated much more rapidly with the help of a comparison of the right toothrow of Stremme's specimen with the corresponding set of cranium 5 of R. sondaicus and drawn (after a photograph) in text fig. 13, than by means of a lot of words.
As to the third difference I may refer to my own table O. Though I immediately admit that still the breadth of P1 (upper), P3 (upper) and M1 (upper) of R. sivasondaicus show the greatest values, we may be absolutely sure that also these differences would disappear, if but we had been able to collect the measurements of some more crania of the recent R. sondaicus.
As, moreover, the other rhinoceros remains, which Stremme described, do not afford any reason for specific distinction I conclude:
The fossil form described by Stremme under the name of R. sivasondaicus Dubois is specifically indistinguishable from the recent R. sondaicus, and must therefore be called Rhinoceros sondaicus Desm. fossilis.
At last our own fossil cranium (specimen a of the tables).
Both from the tables and from comparison of the description of the specimen in question with our enumeration of cranial and dental characters and peculiarities of R. sondaicus appears - without leaving a shade of doubt - that also our form is specifically identical with the recent R. sondaicus, and consequenttly also with Stremme's specimen.
Table.
1. Greatest length of cranium (from tip of nasals to posterior surface of occipital condyles)
2. Greatest width of ditto (interval between outer surfaces of zygomatic arches)
3. Breadth between proc. postorbitales of frontals
4. Transverse width of nasals below vertex of nasal arch
5. Least distance between the cristae fronto-parietales
6. Perpendicular front a line tangential to the summit of occipital crest and vertex of nasal arch to the depression of frontals
7. Greatest breadth of occiput
8. Interval between outer angles of occipital condyles
9. Horizontal diameter of for. magnum
10. Height of occiput (from lower edge of for. magnum to summit of occipital crest)
11. Interval between naso-maxillary notch and tip of nasals
12. Interval between ditto and anterior border of orbit
13. Distance from posterior surface of occipital condyle to anterior border of orbit of the corresponding side
14. Distance from anterior border of orbit to posterior border of meatus auditorium externus.
15. Height of vertex of nasal arch above palate
16. Total length of the seven molars
17. Length of premolar series (measured at the buccal side).
18. Distance between internal extremities of fossae glenoidales
19. Distance between tips of proc. glenoiclales (from middle of top to ditto of other side)
20. Distance from post. surface of occipital condyle to ditto of M3 (upper) of corresponding side
21. Interval between lower edge of for. magnum and median posterior extremity of palate
Table K. (1)
Specimens:
A: Rhinoceros sivalensis (Baker & Durand) 1836, p. 502
B. ?R. sivasondaicus' Stremme, 1911, p. 90, 94.
Own 1 and 2. Our own fossil specimens
Toula = Toula (1902) table, R. sondaicus
Cuv.1 and 2 = Cuvier (1822) p. 37, R. sondaicus
Meas.,A,B,Own 1,Own 2,Toula,Cuv.1,Cuv.2
1,-,598,645,ca. 610,590,-,-
2,-,-,360,391,-,-,-
3,254,194,199,198,184,172,197
4,174,95,111,119,87,87,95
5,-,35,54,-,70,-,-
6,99,-,67,-,-,-,-
7,341,270,304,-,271,294,303
8,195,134,136,-,130,145,132
9,-,48,46,-,46,43,42
10,259,194,197,-,-,196,218
11,-,152,145,ca.140,160,-,-
12,-,108,119,ca.115,117,-,-
13,449,383,398,ca.420,390,390,385
14,-,-,323,-,-,-,-
15,238,152,154,ca.149,-,-,-
16,324,248,272,-,-,248,-
17,-,-,135,-,-,-,-
18,-,86,94,ca.75,-,95,90
19,-,-,143,-,-,-,-
20,-,245,255,267,230,-,-
21,368,283,-,-,ca.329,ca.329,305
Table K. (2)
Specimens of recent R. sondaicus, nos. 1-13.
M,1,2,3,4,5,6,7,8,9,10,11,12,13
1,646,611,641,595,640,639,622,601,616,627,642,634,616
2,354,328,347,339,365,346,337,326,339,325,354,361,354
3,218,167,183,182,183,192,194,173,171,182,204,218,190
4,99,87,88,85,81,93,95,91,94,95,107,107,100
5,c.42,55,67,50,56,69,63,47,46,37,60,62,52
6,59,53,47,60,48,60,59,61,61,57,65,60,58
7,306,281,375,296,289,299,289,291,289,276,302,310,320
8,153,142,130,142,139,144,134,123,145,132,149,145,144
9,50,42,46,45,50,50,48,43,45,45,44,49,45
10,226,204,212,205,226,212,231,205,210,213,229,222,219
11,160,152,159,150,159,157,149,144,153,161,163,151,151
12,117,100,110,97,106,108,103,109,102,102,102,112,102
13,398,374,393,373,400,401,406,369,376,385,400,404,383
14,306,309,330,291,326,323,322,302,304,316,304,328,320
15,c154,144,135,153,136,147,143,164,162,c137,160,148,163
16,250,254,247,-,245,243,257,239,241,266,247,256,250
17,125,133,122,-,125,119,130,126,125,132,128,126,128
18,99,105,96,87,84,92,100,91,88,101,91,90,92
19,141,151,135,130,152,150,161,131,148,147,149,162,142
20,258,241,256,261,274,282,259,239,240,240,264,261,235
21,295,294,313,290,289,c308,303,279,282,290,310,297,c290
End
|
|
|
File available
details
Original text on this topic: