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New Remains of Tragulids (Mammalia Tragulidae) from the Dhok Pathan Formation of Hasnot (Late Miocene) Pakistan.

Byline: Arifa Batool Muhammad Akbar Khan Muhammad Akhtar and Naureen Aziz Qureshi

Abstract

Tragulids especially Dorcatherium are the best represented ruminants in the Middle Siwaliks of Hasnot northern Pakistan. New remains described here predominantly consist of isolated teeth maxilla and mandible fragments. The material is assigned to two tragulid species Dorcatherium minus and D. majus. The extinction of the tragulid species at the end of Early Pliocene indicates the climatic conditions and landscapes experienced drastic change towards dryer and more open environments.

Keywords: Vertebrate Artiodactyla Ruminantia Miocene Pliocene Siwaliks.

INTRODUCTION

The tragulids are the most primitive representatives of the extant ruminants (Janis 1984; Scott and Janis 1993; Hassanin and Douzery 2003; Marcot 2007; Agnarsson and May-Collado 2008). The tragulids having small size in living pecorans are less advanced regarding their morphological and physiological features (Dubost 1965; Kay 1987; MACopyrighttais et al. 2001; RAlssner 2007; Geraads 2010; Sanchez et al. 2010). Six extant tragulid species are present in the Old World: Tragulus spp. in South- East Asia and Philippines (Meijaard and Groves 2004) three or four in India and Sri Lanka (Moschiola spp.) (Groves and Meijaard 2005) and one in tropical Africa (Hyemoschus aquaticus) (Meijaard et al. 2010).

The tragulid remains are common finds in the Lower and Middle Miocene deposits of Africa (Whitworth 1958; Hamilton 1973; Pickford 2001 2002; Quiralte et al. 2008) Europe (Mein 1989; RAlssner 2007; Gentry 1999; Gentry et al. 1999) and South Asia (Mein and Ginsburg 1997; Ginsburg et al. 2001;Sanchez et al. 2010; Khan et al. 2012; Khan and Akhtar 2013).

Fossil Tragulidae are mainly represented by the extinct genus Dorcatherium Kaup and Scholl 1834 with 22 recognized species during the MiocenePliocene (RAlssner 2007) exceeding by far the specific diversity of other genera such as Siamotragulus Thomas Ginsburg Hintong and Suteethorn 1990 Dorcabune Pilgrim 1910 and Yunnanotherium Han 1986. Dorcatherium is amongst the five extinct genera of the family Tragulidae alongside Dorcabune Siamotragulus Yunnanotherium and Archaeotragulus and it has a wide biogeographic distribution that includes Africa and Eurasia (Sanchez et al. 2010; Khan et al. 2012; Khan and Akhtar 2013). The age range of this genus in Africa starts with the Early Miocene and probably extends onto the Early Pliocene (Arambourg 1933; Whitworth 1958; Janis 1984; Fahlbusch 1985; Gaur 1992; Gentry et al. 1999; Pickford 2001; Morales et al. 2003; Pickford et al. 2004; RAlssner 2007; Quiralte et al. 2008).

Dorcatherium remains are known in south Asia especially in Pakistan about 18 Ma (Welcomme et al. 2001; Khan and Akhtar 2013).

The new recovered tragulid material comes from the outcrops nearby the Hasnot village (Lat. 32 49 N: Long. 73 18 E) northern Pakistan (Fig.1A). The Hasnot outcrops belong to the Late Miocene Early Pliocene age (7 to 5 Ma) (Pilbeam et al. 1977; Barry et al. 2002; Khan et al. 2009 2012). Numerous rich fossiliferous sites occur in the vicinity of the village (Fig. 1B). Lithostrati- graphically the Hasnot village belongs to the upper Dhok Pathan Formation (isochronous to the European Late Turolian age) and are characterized by the presence of sandstones with alternate clays and scattered conglomerates in the lower part and conglomerates with sandstones and clays in the upper part of the stratigraphical succession. The sediments composed of orange brown colored clay deposited around 7 to 5 Ma (Pilbeam et al. 1977; Johnson et al. 1982; Barry et al. 1982; Barry 1987; Khan et al. 2009 2012).

The material represents two tragulid species: D. minus and D. majus in the Hasnot northern Pakistan. A strong attachment to wet forested habitats can be assumed for the tragulids where the animals could hide from predators in vegetation or water. However climatic and ecological conditions are different at present in Hasnot northern Pakistan. This paper interprets the entire collection of tragulids recently recovered from the Hasnot outcrops of the Middle Siwaliks.

MATERIAL AND METHODS

Material

The ascribed tragulid material was recovered during 2010 to 2013 in the excavation at Hasnot conducted by the first author for the PhD research work (Fig. 1). The collected tragulid remains include isolated teeth mandible and maxilla fragments. Different methods were used for the collection of the tragulid remains but surface collection remained the primary method of gathering tragulid fossils. Some excavations were conducted at a small number of sites where dense concentrations of fossil bones occur in situ within sandstone deposits alternating with clay and conglomerate. Some fossils were found in the orange brown clay.

The embedded material was cautiously excavated with the help of instruments such as chisels geological hammers fine needles pen knifes hand lances and brushes. The material was carefully washed and cleaned in the Palaeontology Laboratory of Wildlife and Fisheries Department GC University Faisalabad thus being prepared for the taxonomic and morphological determination. Each specimen was assigned a catalogue number that consists of series i.e. yearly catalogue number and serial catalogue number so figures on the specimen represent the collection year (nominator) and serial number of that year (denominator) (e.g. PC-GCUF 12/15 the upper figure denotes the collection year and the lower one represent the serial number of the respective year; PC-GCUF is an institutional abbreviation employed for the Palaeontological Collection of Government College University Faisalabad Punjab Pakistan).

The metric and morphological characteristics of the tragulid remains are determined and systematic determination is discussed. The studied material is housed in the Zoology Department of GC University Faisalabad Pakistan.

The metric and morphological characteristics of the tragulid are determined and systematic determination is discussed.

Photography

Well-preserved specimens were selected for photography and are illustrated in the respective figures. Measurements of the specimens were taken with the help of a metric vernier caliper. The measurements were taken occlusally at maximum level (meso-distal = length labio-lingual = width) and are expressed in millimeters.

Source of the comparative material

Comparison is made to fossils housed in the British Natural History Museum London (BMNH) the American Museum of Natural History (AMNH) the Geological Survey of Pakistan (GSP) Islamabad and Quetta the Geological Survey of India (GSI) Calcutta and the specimens of the Palaeontology Laboratory of the Zoology Department of the Punjab University Lahore Pakistan (PUPC). Dental measurements of the Siwalik Dorcatherium for comparison were also taken from literature (Khan et al. 2012; Khan and Akhtar 2013).

Nomenclature

Tooth terminology generally follows Gentry et al. (1999) Khan et al. (2011 2012) with some exceptions substituting the terms anterior/posterior median ribs by paraconus/metaconus rib (following BArmann and RAlssner 2011). Uppercase letters represent upper dentition (e.g. M1) and lowercase for lower dentition (e.g. m1).

SYSTEMATIC PALAEONTOLOGY

Suborder Ruminantia Scopoli 1777 Family Tragulidae Milne-Edwards 1864

Genus DORCATHERIUM Kaup and Scholl 1834

Type species

Dorcatherium naui Kaup and Scholl 1834.

Generic diagnosis

As in Kaup and Scholl (1834) and RAlssner (2010: 128).

Occurrences

Europe East Africa South Asia.

Time range

Early Miocene Early Pliocene.

Dorcatherium minus Lydekker 1876

Type specimen

GSI B195 right upper first and second molars figured in Lydekker (1876 p. 46 pl. VII figs. 3 7).

Specific diagnosis

As in Colbert (1935).

Type locality

Kushalgar Attock district and Hasnot Jhelum district the Punjab province Pakistan (Colbert 1935).

Stratigraphic range

Middle Miocene Early Pliocene (Lower Middle Siwaliks).

Locality

Hasnot Jhelum district the Punjab province Pakistan.

New material

PC-GCUF 11/178 left M1; PC-GCUF 12/39 probably a partially broken M1; PC-GCUF 11/184 right M3; PC-GCUF 12/40 right m1; PC-GCUF 12/41 left m1; PC-GCUF 10/21 left m2; PC-GCUF 10/54 right mandibular fragment with partial m2-3;

PC-GCUF 12/12 left mandibular fragment of a juvenile animal with posterior lobe of m1 and complete m2.

Description

Upper dentition

The upper molars demonstrate greater width than length (Figs. 2AC; Table I). The molar shows semi buno-selenodonty. The molars have broad and low cusps with strongly developed mesostyle and labial ribs. The paraconus rib is strong whereas the metaconus one is weak. The pre-protocrista is longer than post-proto-crista which is isolated destolingually. The pre-and post-hypocristae are almost equal in length; however the pre-hypocrista is isolated mesiolingually and the post-hypocrista is fused distally with the post-meta-crista. The cingulum is present mesiolingually and it is especially well-developed on the base of the protocone. There is no entostyle.

Table I. Comparative measurements (mm) of the cheek teeth of Dorcatherium minus and Dorcatherium majus. the studied specimens. Comparative measurements are taken from Colbert (1935) Farooq et al. ( 2007a 2008) Iqbal et al. (2011) Khan et al. (2012) and Khan and Akhtar (2013).

Taxa###Number###Nature/Position###Length###Width###W/L

D. minus###PC-GCUF 11/178###lM1###09.7###10.5###1.08

###PC-GCUF 12/39###M1###11.0###06.2###0.54

###PC-GCUF 11/184###rM3###12.8###12.8###1.00

###PC-GCUF 12/40###rm1###10.0###05.1###0.51

###PC-GCUF 12/41###lm1###09.3###05.4###0.58

###PC-GCUF 12/12###lm1###-###-###-

###lm2###08.2###05.5###0.67

###PC-GCUF 10/21###lm2###11.0###07.0###0.63

###PC-GCUF 12/01###lm2###11.0###06.9###062

###PC-GCUF 10/54###rm2###-###07.0###-

###rm3###-###07.0###-

###PUPC 68/210###lm3###18.0###08.0###0.44

###PUPC 87/84###M1###09.3###10.0###1.07

###PUPC 87/40###M1###10.0###11.7###1.17

###GSI 09/01###M1###08.2###10.2###1.25

###GSI 09/02###M3###12.5###13.7###1.09

###PUPC 68/355###M3###11.7###13.0###1.11

###PUPC 02/158###m1###10.6###06.7###0.63

###PUPC 68/313###m1###08.9###05.6###0.62

###PUPC 68/312###m1###09.1###05.3###0.58

###PUPC 68/311###m2###10.0###06.6###0.66

###PUPC 68/312###m2###10.0###06.2###0.62

###PUPC 85/59###m2###09.5###07.0###0.73

###PUPC 02/158###m2###12.7###08.2###0.64

###AMNH 19365###m2###13.0###12.0###0.92

D. majus###PUPC 86/46###rM3###20.0###21.6###1.08

###PC-GCUF 10/49###lp3###13.8###05.8###0.42

###lp4###14.2###07.2###0.50

###lm1###15.5###10.2###0.65

###lm2###17.2###11.2###0.65

###lm3###23.3###12.0###0.51

###PC-GCUF 12/18###lm1###16.6###09.6###0.57

###m2###20.0###10.3###0.51

###PC-GCUF 12/31###lm2###19.0###11.0###0.57

###PC-GCUF 10/52###rm3###27.1###12.1###0.44

###PC-GCUF 11/153###rm3###19.4###-###-

###PC-GCUF 12/29###m3###-###11.2###-

###AMNH 19354###M3###20.5###23.5###1.14

###GSI B198###M3###20.1###19.2###0.95

###PUPC 67/191###M3###13.6###15.2###1.11

###PUPC 87/197###M3###20.5###22.0###1.07

###PUPC 86/02###p4###13.3###06.0###0.45

###PUPC 86/05###p4###13.1###05.7###0.38

###AMNH19524###P4###14.5###05.0###0.34

###GSI B593###P4###17.3###06.2###0.35

###GSI B593###m1###15.7###09.5###0.60

###PUPC 01/21###rm1###17.5###09.0###0.51

###PUPC 86/05###m1###13.0###09.3###0.71

###AMNH 19524###m1###13.5###09.0###0.66

###GSI B593###m2###17.5###10.0###0.57

###PUPC 01/26###lm2###17.0###09.0###0.52

###PUPC 07/09###lm2###18.0###12.0###0.66

###PUPC 63243###m2###17.0###10.1###0.59

###PUPC 84/115###m2###16.0###12.0###0.75

###PUPC 86/02###m2###15.6###09.8###0.62

###PUPC 86/05###m2###15.0###11.1###0.74

###PUPC 86/152###m2###16.2###12.0###0.74

###PUPC 98/61###m2###17.0###10.5###0.61

###AMNH 19520###m2###17.0###10.5###0.61

###AMNH 19524###m2###16.0###11.0###0.68

Lower dentition

The lower dentition specimens described here include first and second molars and two fragile mandibular fragments (Figs. 2D-F 3A-B; Table I). The teeth are subhypsodont and narrow crowned. The major conids are well preserved. The lingual conids are pointed and slightly higher than the labial ones. The pre-metacristid is longer than the post- metacristid. The pre- and postfossettes are crescent. A rudimentary ectostylid is present at the base of the transverse valley. A well-developed cingulid is present labiolingually. The post-metacristid (in some sample post-protocristid) is bifurcated indicating Dorcatherium fold a characteristic feature of the genus Dorcatherium. The Dorcatherium fold is directed posteriorly. The metaconid rib and stylid are weakly developed. A prominent entoconid rib is present but the entostylid is weak. The prefossette is less deep than the postfossette.

The postfossette is not fused lingually and consequently the entoconid is completely separated from the hypoconid.

Comparison

The studied specimens prove their inclusion in the family Tragulidae based on the selenobunodont to selenodont pattern with strong cingula and cingulidae and mostly strong styli and stylidae (Rossner 2007; Khan et al. 2012; Khan and Akhtar 2013). Tragulidae in the Siwaliks are represented by two genera Dorcatherium and Dorcabune with many species. Dorcabune is a large extinct tragulid of the Siwaliks and close to anthracotherioides having bunodont molars. The paraconus rib is more conspicuous in Dorcabune than in Dorcatherium (Colbert 1935; Farooq et al. 2007a b; Khan and Akhtar 2013).

The studied specimens differ from Dorcabune showing selenodont cusp/conid pattern (crescentic cusp/conids). The teeth are characterized by well-developed styli/stylidae the basal cingulum in the upper molars and the vestigial ectostylid and Dorcatherium-fold in the lower molars. These characteristics associate them to the genus Dorcatherium. In Dorcatherium the lower molars show a special crest complex called Dorcatherium fold'. The Dorcatherium fold represents a double fold protoconid. It is formed by the bifurcation of post-protocristid and post-metacristid resulting in a ' shape.

The Siwalik Dorcatherium is represented by four species D. majus D. minus D. nagrii and D. minimus (Colbert 1935; West 1980; Farooq et al. 2007a b; Khan and Akhtar 2011; Khan et al. 2012). Dorcatherium majus is the large Siwalik species of Dorcatherium (Farooq et al. 2008; Khan et al. 2012). Dorcatherium minus is more brachydont than D. majus (Khan and Akhtar 2013).

Dorcatherium nagrii and D. minimus are minute species of the Siwalik tragulids (Khan and Akhtar 2011). Dorcatherium has semiselenodont teeth and its numerous species mainly differ by their size (West 1980; Farooq et al. 2007a b 2008; Iqbal et al. 2011; Khan et al. 2012; Khan and Akhtar 2013).

The sample matches well with D. minus morphometrically (Table I; Figs. 2-3). The molars clearly overlap in size with the type material and earlier ascribed material of D. minus. However the spectrum of intraspecific size variability in Dorcatherium is large and enables sexual dimorphism in body size to be hypothesized. However in extant tragulids females are a little larger than males (Dubost 1965; Terai et al. 1998) as is generally true for small ruminants (Loison et al. 1999). Therefore the same dimorphism can be assumed for D. minus.

Dorcatherium majus Lydekker 1876

Type specimen

GSI B197 right upper first and second molars figured in Lydekker (1876 p. 44 pl. VII figs. 4 6 9 10 11).

Specific diagnosis

As in Colbert (1935).

Type locality

Hasnot Jhelum district the Punjab province Pakistan (Colbert 1935).

Stratigraphic range

Middle Miocene Early Pliocene (Lower Middle Siwaliks).

Locality

Hasnot Jhelum district the Punjab province Pakistan.

New material

PUPC 86/46 right M3; PC-GCUF 10/49 left hemimandible with broken p2 and complete tooth series p3-m3; PC-GCUF 12/31 left m2; PC-GCUF 12/18 left mandibular fragment with m1-2; PC- GCUF 10/52 right m3; PC-GCUF 11/153 broken right m3; PC-GCUF 12/29 partially preserved left m3 with missing anterior lobe.

Description

Upper dentition

The newly discovered upper dentition includes the third molar PUPC 86/46 (Fig. 4A). The molar is quadrate in its general appearance rugose and subhypsodont. The molar represents strong labial styles lingual cingulum and semiselenodonty. The cingulum is surrounded by the protocone and the hypocone. There is a lingual cingulum at the base of the protocone and thick cingular shelves extending mesiolingually and distolingually. The parastyle mesostyle metastyle and paraconus ribs are very strong. The post-paracrista and pre- metacrista are connected in a low position on the crown but they are not directly attached to the mesostyle. The fossettes are deep and open in the transverse valley. The lingual lobes are more crescent-shape than the labial ones. The paracone has a strong anterior groove descending from its apex to the base of the crown which separates the parastyle from the labial pillar. The post-hypocrista terminates in the midline of the crown at the distal cingulum.

Mandible

The mandible fragment is broken vertically during the excavation which is assembled. The anterior and posterior parts of the fragment are damaged. There are no preserved parts of the symphysis and angular process. The jaw is shallow and slim with a mental foramen below the anterior root of the p2. The body of the mandible descends anteriorly and is markedly higher under the m3 than under the p2. The ventral border of the body of the mandible is weakly curved downward. Apart from the relatively long mandible (ML = 154 mm) the mandible fragment is shallow and slim as is typical in tragulids (Fig. 5A; Table I). The jaw deepens rapidly distally being 20 mm deep below the p3 and 37 mm below the m3. The ascending ramus begins right at the posterior end of the hypoconulid so there is no gap between the m3 and the ascending ramus. The lingual surface of the jaw is marked by a groove distolaterally.

The labial side of the hemimandible is clearly convex anteriorly and the lingual side is slightly concave below the m1. The molar series length is 55 mm and the premolar series is 40 mm long.

Lower dentition

The p1 is absent. The p2 is broken anteriorly (Fig. 5). The posterior lobe of the p2 representing a short lingual entocristid originating at the hypoconid. The p3 is longish - a tragulid feature with three labial conids (protoconulid protoconid hypoconid). The p2 has two conids (protoconulid protoconid). The p4 is shorter than p3: the p3 is slightly more elongated than the p4. In the p3 a strong protoconid linked by a straight longitudinal crest to a small mesio-lingually situated paraconid. The latter crest is slightly curved lingually and joins the more lingually situated paraconid. The conical hypoconid is weaker and lower than the protoconid located behind a strong protoconid at the posterior of the premolar. The hypoconid forms a well- marked transverse spur posteriorly on the p3 where it delimits a small lingually open vertical basin.

The p4 is the widest of the premolars owing to a lingually located post-protocristid. In the p4 the pre-protocristid is curved anterolingually with paraconid which is more lingually situated. The pre- protoconulidcristid runs straight mesiolingually. The pre-protocristid joins the paraconid and two parallel crests extend from the apex of the strong protoconid to the distal border of the premolar forming a triangular and narrow basined talonid. The anterior valley is opened lingually. The entoconid complex is absent a tragulid feature. A short distolabial crista at the hypoconid is absent. The p1 p2 and p3 are two-rooted.

The trigonid is narrower than the talonid in the m1. The lingual conids are transversely compressed owing to the large size of the hypoconid. The labial conids are crescent shape. The anterior cingulum is slightly extending on the labial side of the protoconid. The post-protocristid is bifurcated into Dorcatherium fold connected with the outer flank of the well-marked Dorcatherium fold at the rear of the metaconid and open at the lingual base of the metaconid on worn tooth. The fusion of both crests into a single edge joining the pre-entocristid involving an ' shape on the posterior side of the trigonid. The entoconid is rounded posteriorly and situated forward with respect to the hypoconid displaying a deep groove opens lingually on the unworn m3.

The post-hypocristid extends disto-lingually reaching the post-hypoconulidcristid lingually. The hypoconulid of m3 labially twisted and transversely compressed with one crest extending forward from the apex of the hypoconulid to reach the post- hypocristid labially of the second lobe without any accessory small tubercle. The lingual crest of the hypoconulid units with lingual cingulid is extending between the hypoconid and hypoconulid lingually. The weak ectostylid like labial cingulid is present in the transverse valley. The pre-fossette is not crescent shape but it is somewhat compressed and straight whereas the post-fossette is crescentic and opens distolingually.

Comparison

The studied material presents semi- selenodonty isolated strong style basal cingula/cingulid prominent paraconus rib and the presence of -structure (Dorcatherium fold) in the lower molars. The material characterized by these features can be associated with tragulids (MACopyrighttais and Vislobokova 2007; RAlssner 2010; Khan et al. 2012; Khan and Akhtar 2013). Siamotragulus and Yunnanotherium differ from those of the studied samples in: more selenodont and hypsodont aspect premetacristid is well developed and closes the anterior side of the trigonid and a strong ectostylid (Thomas et al. 1990; Vislobokova 2001). Afrotragulus Siamotragulus Yunnanotherium Moschiola and Tragulus teeth differ from the studied specimens in having flat cusps. They are characterized by the presence of flat main cusps with cristids that are elongated and vertically developed (Sanchez et al. 2010).

Nevertheless the features reflected by the studied specimens associate them to Dorcabune Hyemoschus and Dorcatherium. Dorcabune differs from that of the studied material in: very bunodont conical molars thick and rugosed enamel well developed cingulum the presence of the double fold' on the protocone of the upper molars and a well-pronounced M structure with a double fold on the posterior side of the protoconid on the lower molars (Pilgrim 1915; Khan et al. 2012). The studied molars differ from those of Hyemoschus in: weak cingulum semiselenodont (= bunoselenodont) cusps/conids pattern and the orientation of the post- protocristid (Pickford 2002; Morales et al. 2003; Pickford et al. 2004).

On the basis of the selenodont upper molars with strong cingulum styles and labial ribs and the presence of the structure (Dorcatherium fold) in the lower molars the specimens are attributed to Dorcatherium rather than to Hyemoschus or other Miocene tragulids such as Dorcabune (Khan et al. 2012) and Siamotragulus (Thomas et al. 1990) or extant ones such as Tragulus.

The teeth are much closer morphometrically to the Siwalik Dorcatherium majus (Table I; Fig. 4- 6). The teeth of D. majus are larger than those of D. minimus D. minus and D. nagrii (Table 1) and morphologically they differ from D. minus and D. nagrii in terms of the strong basal cingula and the stronger and larger styles (Fig. 4-5) (Lydekker 1876; Pilgrim 1915; Colbert 1935; Farooq et al. 2007b 2008; Khan et al. 2012).

DISCUSSION

Tragulids representing the best-described ruminant family of the Late Miocene (Vislobokova 2001; Pickford 2002; Khan et al. 2012) have been found in the Hasnot outcrops (Farooq et al. 2007c 2008; Khan et al. 2012). The presence of Tragulids (Dorcatherium) suggests highly humid ecological conditions with habitats of small swamps and patches of dense forests (Meijaard et al. 2010; Khan et al. 2012). Living chevrotains favor dense habitats of the rain forests (Dubost 1978; Meijaard et al. 2010) which serve as shady shelters from predators. Their dry-land dietary habits include fruits and leaves whereas the species apparently can enter water for the purpose of safety (Dubost 1978). The presence of the tragulid fossils in the Late Miocene of the Siwaliks indicates the presence of dense pockets of rain forest.

Dorcatherium majus and D. minus are typical representatives of the browsing guild such as Dorcabune Eotragus Elachistoceros Tragoportax Miotragocerus Selenoportax and Pachyportax (Thomas 1977 1984; Solounias et al. 1995; Barry et al. 2005; Bibi 2007; Khan et al. 2010 2012; Khan and Akhtar 2013). These species fed on a broad array of leaves shoots and buds with high protein content as well as on limited amounts of vegetation with abrasive particles (Bouvrain 1994; Khan et al. 2009 2010 2012) and found their food in lowland forests and ecotones to open areas (Stuart and Stuart 1997; Geist 1998).

Dorcatherium majus and D. minus are indicated to have had a browsing diet with a wide spectrum including water plants and occasional fruit and grass intake. The difference between feeding strategies of Hyemoschus and Dorcatherium suggests the use of different ecological niches. Nevertheless both the genera must have overlapped in wet forested habitats (Dubost 1978; Stuart and Stuart 1997). Closed low canopy forest with minimal ground cover would have been suitable for Dorcatherium on a limited home range.

CONCLUSIONS

The Hasnot tragulids are placed in Late Miocene to Pliocene age based on its associated fauna of the Late Miocene to Pliocene taxa such as Selenoportax Pachyportax Tragoportax and Hipparion. The tragulid-associated fauna shows abundant vegetation with significant food supply for the diversified mostly brachydont large mammalian fauna. An association of tragulids with other artiodactyls indicates the existence of habitats with humid conditions along with open drier areas. The Hasnot area is suggestive for such a mosaic of both more open and forested landscapes with an enormous wetland environment strongly subjected to alternating dry and flood seasons.

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Author:Batool, Arifa; Khan, Muhammad Akbar; Akhtar, Muhammad; Qureshi, Naureen Aziz
Publication:Pakistan Journal of Zoology
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