110

extremely large, and the occipital region of the skull is raised.

These head muscles, the sterno and cleidomastoid, must have been

powerful and provided the force behind the teeth. The sabres them

selves form excellert slicing blades, and the whole mechanism is a

better method of piercing a thick hide than in the "normal" method

of lion or leopard.

Another view has been put forward by Bohlin (1940, 1947) who

argued that the canincs were too slim and fragile to be used to kill

at all, and these animals were entirely carrion-eating. He adds

that in making the killing bite, the head would have to come so far

back that tne line of vision would be obscured, and the teeth easily

broken by stabbing on to bone. A number of point3 are against this

hypothesis. Firstly, it is unlikely that a carnivore of any great

size can subsist by scavenging alone, as recent, work has shown

(Schaller 1972), the number of carcasscs they may have come across could

not have been that many. Usually the primary predator consumes most

of the meat and what is left is finished off by hyaenas. Hyaenas,

contrary to popular belief, are not solely carrion-eaters, and they

are successful pack-hunters (Van Lawick - Goodall 1970). Secondly,

a hyaena's dentition is adapted to dealing with the tough remains of

a carcass, such as tendons, cartilage, bone; the pre-molars are sturdy

and conical and the carnassials are not the narrow slicing structures

of the ma, haerodont?. The latter, with the reduced pre-molars and

scissor-l’ke carnassials could only have eaten the choice meat of

freshly killed prey.

It is peculiar thut even among the earlier forms, the highly

specialized end lines (such as Kusmilus. Hoplophoneus and Sansano-

smilus) have carnassials much better adapted for a carnivorous diet

Ill

than have the modern cats, which have had an equally long evolutionary

history in which to achieve the same thing. It is suggested here that

because of the weak temporalis and masseter muscles, the lower jaw

of the machaerodonts could not have exerted a strong pressure in chew

ing. To compensate for this, the molars became more important, which

resulted in reduction of pre-molars and more blade-like carnassials.

Little pressure is needed to cut something with sharp scissors whereas

more pressure is necessary when using blunt scissors. The living cats

do not have t) s problem as the jaw muscles are powerful. In fact,

lion, leopard and tiger readily scavenge (Turnbull - Kemp 1972). In

one survey sixteen per centum of a lion's food was found to bo

obtained from carrion, and they are even known to drive hyaenas away

froi the pack's kill (Schaller 1972).

Matthew (1910) believes that the sabre-tooths tors at the

softer belly of the prey so that it bled to death. Churcher (per. comm,

offers a more satisfactory idea; that they attacked the soft under

side of the neck after gripping with the forjlimbs and claws. The

throat is extremely vulnerable, and veins, nerves and trachea can be

severed with one slash, and there is no bone to risk breaking the

teeth. Moreover, leaping at the belly, there is the danger of being

hit on the head by hooves. Lions usually bring the prey down first by

grabbing with the fore paws, then biting the nape or throat. (Schaller

1972). This could also be envisaged for Megantereon or Smilodon whose

forequarters were massive and powerful.

The two types of Pleistocene sabre-tooths, the homotheriines

and the smilodontines were quite differently constructed which suggests

that they each occupied a different ecological nich. Added to this is

the fact that the fossils are nearly always found together in the same

Ill

than have the modern cats, which have had an equally long evolutionary

history in which to achieve the same thing. It is suggested here that

because of the weak temporalis and masseter muscles, the lower jaw

of the machaerodonts could not have exerted a strong pressure in chew

ing. To compensate for this, the molars became more important, which

resulted in reduction of pre-molars and more blade-like carnassials.

Little pressure is needed to cut something with sharp scissors whereas

more pressure is necessary when using blunt scissors. The living cats

do not have this problem as the jaw muscles are powerful. In fact,

lion, leopard and tiger readily scavenge (Turnbull - Kemp 1972). In

one survey sixteen per centum of a lion's food was found to be

obtained from carrion, and they are even known to drive hyaenas away

from the pack's kill (Schaller 1972).

Matthew (1910) believes that the sabre-tooths tore at the

softer beily of the prey so that it bled to death. Churcher (per. comm,

offers a more satisfactory idea; that they attacked the soft under

side of the neck after gripping with the forelimbs and claws. The

throat as extremely vulnerable, and veins, nerves and trachea can be

severed with one slash, and there is no bone to risk breaking the

teeth. Moreover, leaping at the belly, there is the danger of being

hit on the head by hooves. Lions usually bring the prey down first by

grabbing »ith the fore paws, then biting tho nape or throat. (Schaller

1972). This) could also be envisaged for Megantereon or Smilodon whose

forequarters were massive and powerful.

The two typeu of Pleistocene sabre-tooths, the homotheriines

and the smilodontineM were quite differently constructed which suggests

that they each occupied a different ecological nich. Added to this is

the fact that the fossils are nearly always found together in the same

112

deposit, which means that they were compatible in the same aroa. The

smiiodontines, with their short, stocky legs, shortened rather inflex

ible lumbar region and heavier build were probably woodland dwellers,

as they were obviously poor runnrrs. They probably leapt from ambush

(Churcher per. comm.). The homotheriines were built more in proport

ion with the modern lion or leopard, but still showed a tendency for

strengthening of the forebody and shortening of the legs. They

probably frequented the plains, were relatively faster runners and

preyed upon the more light-limbed creatures, such as primitive gazelles,

pigs and horses. In many cases, the bones of juvenile elephants are

associated ,-ith Homotherium. suggesting that they preyed upon these but

not the adults (Kurten 1968). In both types, the tails were extremely

short, but +here are a variety of reasons for this.

The origin and spread of Dinofolis from the basic feline stock

illustrates the repeated tendency among fossil cats for machaerodontine

development. This genus did not, however, get very far before

environmental conditions exterminated the entire group of machaero

donts. That it was among the dominant carnivores during Pleistocene

times in Africa seems to bo becoming more evident, and in fact it

appears to have been much more widespread than originally thought. It

is now known from India (a Pel i s cri stats) and America («Panthera

palaeonca).

In the Upper Pliocene, the genus Panthera makes its first

appearance. It was obviously better adapted for a cursorial habit

and with the changing fauna, became the dominant feline carnivore. It

is represented in the Transvaal caves (Ewer 1956°), in East Africa

(Leaker 1967, Maglio 1972), and other Pleistocene deposits in forms

not much different from today's.

With the increasing scarcity of the pachyderms, the machaerodonts

113

became less abundant. The last remnants reach the height of

specialization and increased in size, probably because their prey

became limited to even larger types.

4.3 The ph\logony of the Machacrodontinao

Most of the more ancient fossil cats are typified by enlarged, sabre

like upper canines, and it was not until the late Pliocene that cats

with "normal" canines made their appearance (Matthew 1910). In

Matthew's opinion, the Tert1 -.ry and Quaternary sabre-too'*.hs can be

derived from one of the specialized Oligocene sabre-tooths,

Hoplophoneus. The contemporary Dirictis which was less specialized

led to the modern cats (Felinae) through Nimravus and Pseudae1urus.

the sabres gradually getting shorter and more conical.

In a more general fashion, Teilhard and Leroy (1945) and

Piveteau (1948) divided the family Felidae into Palaeo-felids (Oligo

cene) and Neo-felids (post Oligocene) in both of which there are

machaerodontinoid and felinoid branches. The Palaeo-felids can be

distinguished from the Neo-felids by possessing an alisphenoid canal,

and distinctly separa+e carotid, posterior lacerate and condylar

foramina, on the basicranium. In the younger Felidae, thp alisphenoid

canal disappears, and the three foramina show an increasing tendency to

uni te.

Simpsun (1945) agrees with Matthew in placing Pseudaelurus

ancestral to the Felinae, and the Nimravus not far from it. He however

places all the machaerodontine cats (including the Oligocene forms)

into tho sub-family Machaerodontinae. He considers Dinofeli s belongs

to the Felinae.

lue derivation of the "false sabre-tooths" is from the Chinese

Lower Pliocene Metailurus (Ewer 1955). Mctailurus seems indistinguishable

from t'ie Miocene Pseudaelurus and Matthew (1929) considers them

generally nseparahle, -but that Metai lurus represents a stage leading

towards Fell s. Savage (1965), on the Miocene M. afri.canus agrees with

Matthew. Stock (1934) however, has pointed out -Ve more primitive

features ol‘ Pseudaelurus, such as the g ater number of pre-molars and

the possession of an alisphenoid canal; which certainly seems to warrant

generic separation. The American P. intrepidus has non-serrate upper

canines (Stock 1934) while the European P. quadridentatus has finely

serrated upper canines, and al30 lower incis (Ginsburg 1961). In

both cases the teeth are moderately long and flattened.

The position and affinities of Me tailurus are rather uncertain,

as in Viret's opinion it is closely related to Dirofeli s (Ewer 1955),

and the canines are also moderately long, although in nearly all

other aspects the skull is feline in character (Zdansky 1 9 2 4 ) . The

upper canines are not serrated and the reduction of the pre-molars is a

trend shared by both Felinae and early Machaerodontinae. Hemmer (1956)

agrees that Pi nofeli s can be derived from a nimravid stock but that an

intermediate species has yet to be discovered.

A more recent contribution to the phlogeny of the Felidae

been suggested by Thenius (1967) in which the difficulties of taxonomic

division in this family are expressed, due to the many independent

parallel developments leading to superficial resemblances. Thenius

recognises five sub-families; the Eocene Proailurinae at the base of

the stock, the Oligocone Nimravinae and Hoplophonidao, and the Pliocene/

Pleistocene Machaerodontinae and Felinae. The Nimravinae and Hoplophoni-

dae are nowhere ancestral to the later cats but branched off from the

Proailurinao at a very early stage. The Miocene Sansanosmilus and

Busmi lus are extremely specializ'd end forms while ?Ji mravus and Dini cti s

are less specialized side branches. The skull of Nimravus looks very

much like that of a primitive feline, although the canine? are inequal

114

115

in size and slightly serrated (Toohey 1959).

The Felinae and Machaerodontinae both have their origins in the

Proailurinae with Pseudaelurus as the intermediate stage. Machaerodus

is derived from an early Pscudae]urns (perhaps related to P. quadri-

dentatus?) and a later form gave rise tc both the Felinae ana Metai1-

urus. The latter is considered ancestral to Dinofelis, The "false

"Rbre-tooths" are thus considered as Felinae and the most closely re

lated to modern cats.

The separation of Pant hora and Feli s within the Felinae is first

seen in the Upper Pliocene, with Lynx branching off at an earlier

stage, and the origin of Acinonvx rather uncertain. Apparently

Cryptoprocta. the ferret cat from Madagascar is a survivor from the

Proailurinae.

Within the Machaerodontinoe, Homotherium and Meganteroon/Smilodon

are bot\ derived frcm Machaerodus. Kurten (1963) separates them into

tribes Hew theriini and Smi lodon tiri,

T ienius (1967) considers a Eurur i u ’igin for the Felinae, with

migration into .itri* . Ewer (1^55^ not» . the African Megantereon

eurynodcn ard Pi nolo V

1]6

noted an analogous utuation in the lynx, which is unique among modern

Felinae in frequently possessing a post-c,-nassial complex (talonid,

metaconid and M^) in the lower dentition. It apparently has made a

reappearance in the lynx (Kurten 1963).

The clouded leopard, Neofolis nebulosa has sometimes been quoted

as a living cat showing slight machaerodontine signs, as it has exception

ally long canines. However, the lengthening is in both upper and

lower canines, and there is no great difference in size between them

(Grey 1867). The >ipper canines show no sign of narrowing either and

the jaw still operates in the same way as other felines N. nebulosa

is arboreal with short, stout legs and broad paws, rather reminiscent

of Smilodon and Megantereon. This might suggest that the latter were

also arboreal, although N. nebulosa has a long body and an extremely

long tail (Walker 1964). The shortening of the tail in all the later

Machaerodontinae could have a variety of reasons, but among extant

Felidae, only the lynx American bobcat and manx have short tails. The

African lynx, or caracal, is long-legged and plains-dwelling.

4.4 The ac. /f the deposit

According to the most recent estimations on the age of Makapansgat,

it is generally agreed that the deposits accumulated between three to

four million years ago. /is regardsfossi1 correlation with the

European Pleistocene, it seem? that the African "Villafranchian"

occurred at an earlier date than the European Villafranchian, although

there is no fixed agreement as yet on the definition of the term

"Villafranchian".

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Author Collings G E Name of thesis Some New machaerodonts from Makapansgat limeworks 1973

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