STEGODON BOMBIFRONS FROM THEPINJOR STAGE, SOAN FORMATION OF JARIKAS, AZAD KASHMIR, PAKISTANSADAF ASLAM, ABDUL MAJID KHAN, MUHAMMADAKBAR KHAN*, ABDUL GHAFFAR**, MUHAMMADAKHTAR AND KHIZAR SAMIULLAHDEPARTMENT OF ZOOLOGY, UNIVERSITY OF THE PUNJAB,LAHORE*DEPARTMENT OF ZOOLOGY, GC UNIVERSITY, FAISALABAD** DEPARTMENT OF METEROLOGY, COMSATS ISLAMABAD
INTRODUCTION Proboscideans were the evolutionary taxa ofelephants that are the largest land animalsnow living. Two genera of the family Elephantidae:Elephas and Loxodonta are living today. All other species and genera ofProboscideans are extinct now. The Asian and African elephants divergedfrom a common ancestor some 7.6 millionyears ago.
EXTANT GENERA OF ELEPHANTS AFRICAN ELEPHANTSingle species with two subspecies. AFRICAN SAVANNA / BUSH ELEPHANT(Loxodontaafricana africana). AFRICAN FOREST ELEPHANT (Loxodonta africanacyclotis).
ASIAN ELEPHANTThree subspecies. Sri Lankan elephant (Elephas maximus maximus),only found on the island of Sri Lanka. Indian elephant (Elephas maximus indicus),foundin India. Sumatran elephant (Elephas maximussumatranus), found only on Sumatra.
DIFFERENCE BETWEEN AFRICAN AND ASIANELEPHANT The African elephant is typically larger thanthe Asian elephant and has a concave back. African elephants have larger ears. In Asian elephants, only males have tusks,but both males and females of Africanelephants have tusks.
OBJECTIVESTo study stegodon fossils from 2.6-0.6 millionyears old.
STUDIED SECTIONTHE SIWALIK SEDIMENTS ALONG THE FOOTHILLS OF HIMALAYAS.
JARI KAS An approx. 1km thickness of upperSiwalik subgroup rocks in the southernPotwar Plateau and south western Kashmir.
MATERIALS AND METHODS The specimen was collected from Upper Siwaliksduring geological survey. The specimen was thoroughly washed in thelaboratory. The specimen was catalogued such as PUPC(Punjab University Palaeontological Collection)2010/16. The upper figure denotes the collectionyear, while the lower one is the serial number of therespective year. The measurements of the specimen were made byMetric Vernier Callipers. The specimen is housed in paleontological laboratory,Department of Zoology, University of the Punjab,
DIAGNOSTIC FEATURES Cranium compressed anteroposteriorly with convexskull vertex. Tusks small. Cement gradually increases in the successive teeth. Enamel very thick. Teeth broad and large. Usually a trace of median longitudinal cleft present inanterior ridges. Inner columns of ridge-plates occasionally showaccessory tubercles near the longitudinal cleft.(Sarwar, 1977).
STUDIED SPECIMENS WITH RELEVANT LOCALITYTaxon Specimen Position Formation/LocalityCo- ordinatesStegodonbombifronsPUPC No.2010/16Skull withupperdentition.Pinjor (JariKas, Mirpur)33 06 236 N73 50 012 E
DESCRIPTION Most part of the cranium is damaged, onlypalate is preserved and visible. The teeth are characterized by large size, broadcrowned, low ridge. Enamel is thick and rugose. Teeth are in middle wearing stage. Cement gradually increases in the successiveteeth. Ridge plates are widely spaced at their summit.
CRANIUM SHOWING OCCLUSAL VIEW, SCALE BAR50MM.CementPalateConeletsDentineEnamelRidge plateAnterior sidePosterior side
RIDGE PLATES FORMULA OF STEGODON TEETH DP3 4-4½ DP4 5 - 6 M1 6 M2 6 - 7 M3 7½-9½8- 9½6 ½-87-7½5½-74-4 ½
DISCUSSION In the past, stegodonts were believed to bethe ancestors of the true elephants andmammoths, but it is currently believed thatthey have no modern descendants. Stegodon is derived from the genusStegolophodon, an extinct genus known fromthe Miocene of Asia. Stegodon is considered to be a sister groupof the mammoth, as well as the elephants
FOSSILS OF STEGODON FROM THE WORLDUptil now fossils of Stegodon have beenrecovered from Indonesia, China, Thailand, Japan Africa Pakistan
DATA SHOWING NUMBER OF RIDGES AND DENTALMEASUREMENTS IN DIFFERENT SPECIES OF STEGODON (DATAUPDATED FROM VAN DEN BERGH 1999).SPECIES No. of ridge plates L (mm) W (mm) W/L indexS. bombifrons 71/2-91/2 253-282 93-108 37-38S. pinjorens 141/2-1 360 130 36Stegodondhokawanensis61/218393 51S. insignis 81/2-111/2 233-287 86-106 37
CONCLUSION Stegodons were present in Jari Kas areas ofAzad Jammu and Kashmir during the latePliocene (about 2.6 mya) along with crownelephant group.