ABSTRACT
Bones of forelimb were studied from a prepared skeleton of an adult female Asian elephant (Elephas maximus) in Anatomy Museum of Chittagong Veterinary and Animal Sciences University to understand the morphological form and structure of Asian elephant forelimb. The angle was approximately 123 between caudal border of scapula and caudal border of humerus. The scapula, humerus and bones of the antebrachium (particularly the ulna) were massive bones. The bones of manus were the short and relatively small. The dorsal border of scapula extended from the level of proximal extremity of first rib to the middle of the 6th rib. Ventral angle of scapula articulated with humerus by elongated shaped glenoid cavity (cavitas glenoidalis) of scapula and head of humerus (caput humeri). The major tubercle (tuberculum majus) of humerus was situated laterally to the head, which had smaller cranial part with large caudal part and extended cranially to the head. The crest of minor tubercle (tuberculum minus) was present as the rough line on the mediocaudal surface of humerus that ends in a slight depressed or elevated area, known as teres major tuberosity (tuberositas teres major). The lateral supracondyler crest (crista supra condylaris lateralis) at the caudal surface of the shaft limit the musculo-spiral groove in body of humerus. The radius and ulna are twin bones of forearm and the attachment between ulna and radius occurs in such a way, the radius articulates craniomedially with the ulna in the proximal part. But the shaft spirals laterally over the cranial surface of the ulna to articulate distally with the medial aspect of the ulna. There were 8 carpal bones, 5 metacarpal bones and 5 digits. The comparative size of the proximal and distal raw of carpal bones were ulnar carpal > radial > intermediate > accessory carpal and IV > III > II > I respectively. The gradual lengths of the metacarpal bones were III > IV > II > V > I. Digits I and V were vertical and digit II, III and IV were horizontal.
En el Museo de Anatomía de la Universidad de Veterinaria y Ciencias de Animales de Chittagong fueron estudiados los huesos del miembro torácico de un esqueleto preparado de un elefante asiático (Elephas maximus), hembra adulta, para analizar su morfología y estructura. El ángulo entre el margen caudal de la escápula y el margen caudal del húmero era de aproximadamente 123°. La escápula, húmero y los huesos del antebrazo (en particular la ulna) eran huesos macizos. Los huesos de las manos eran cortos y relativamente pequeños. El margen dorsal de la escápula se extendía desde el nivel de la porción proximal de la primera costilla para la parte media de la sexta costilla. El ángulo ventral de la escápula está articulado con el húmero por la cavidad glenoidea (cavitas glenoidalis), de forma alargada, de la escápula y la cabeza del húmero (caput humeri). El principal tubérculo (tuberculum majus) del húmero estaba situado lateralmente a la cabeza, que tenía una parte craneal pequeña y una mayor parte caudal, extendiéndose cranealmente en la cabeza. La cresta del tubérculo menor (tuberculum minus) estaba presente como la línea áspera sobre la superficie mediocaudal del húmero que termina en una pequeña zona deprimida o elevada, conocida como tuberosidad redonda mayor (tuberositas teres major). La cresta supracondilar lateral (crista supra condylaris lateralis) en la superficie caudal del eje limita la ranura músculo-espiral en el húmero. El radio y la ulna son huesos gemelos del antebrazo y la unión entre la ulna y el radio se produce de tal manera, que el radio articula, craneal y medialmente, con la ulna en la porción proximal. Pero el eje en espiral está ubicado lateralmente sobre la superficie craneal de la ulna para articular distalmente con la cara medial de la ulna. Se identificaron 8 huesos del carpo, 5 metacarpianos y 5 dígitos. El tamaño comparativo de las porciones proximal y distal de los huesos del carpo fue ulna > radial > Intermedio> carpiano accesorio y IV > III > II > I, respectivamente. Las longitudes graduales de los huesos metacarpianos eran III > IV > II > V > I. Dígitos I y V eran verticales y dígitos II, III y IV fueron horizontales.
Subject(s)
Animals , Female , Elephants/anatomy & histology , Humerus/anatomy & histology , Scapula/anatomy & histology , Ulna/anatomy & histology , Asia , Radius/anatomy & histologyABSTRACT
Recent excavated skeleton of an adult female Asian Elephant (Elephas maximus), died in dystokia in Bangladesh was used for macro anatomical study. Some unique morphological features of bones of hind limb were observed. Pelvic canal was more oval and the wings of ilium were wider. Rump slope was about 36°. Angle between femur and tibia was close to 180°. In Femur, the major trochanter was located at the lower level of head. Minor trochanter, fovea capitis and trochanteric ridge were absent. Supracondyloid fossa was shallow but the intercondyloid fossa was deep. Posterior surface of patella possessed a blunt vertical ridge. The articular surfaces of both tibial condyles were clearly concave. The tibia and the fibula were articulated proximally and distally with keeping a wide interosseous space. Instead of tibial tuberosity, there was an elongated triangular depression in proximal part. There were six tarsal bones arranged in three rows. The comparative size of the distal tarsal bones were III+IV > I > II. The comparative lengths of the metatarsal bones were III > II > IV > V> I. Digits I and V were the most vertical and digit III was the most horizontal. The proximal phalanx was the biggest of all.
Fue utilizado para su estudio anatómico macrocroscópico, el esqueleto de un elefante asiático (Elephas maximus) hembra adulta, excavado recientemente y con muerte por distocia en Bangladesh. Se observaron algunas características morfológicas únicas de los huesos de los miembros posteriores. El canal pélvico era más ovalado y las alas del ilion eran más amplias. La pendiente de la rabadilla era de unos 36° aproximadamente; el ángulo entre el fémur y la tibia era próximo a los 180°. En el fémur, el trocánter mayor se encontraba en el nivel inferior de la cabeza. El trocánter menor, la fovea capitis y cresta del trocánter estuvieron ausentes. La fosa supracondílea era superficial, mientras que la fosa intercondílea era profunda. La superficie posterior de la patela poseía una cresta vertical sobresaliente. Las superficies articulares de ambos cóndilos tibiales eran claramente cóncavas. La tibia y la fíbula se articulan proximal y distalmente, manteniendo un amplio espacio interóseo. En lugar de la tuberosidad tibial, había una depresión triangular alargada en parte proximal. Se observaron seis huesos del tarso dispuestos en tres filas. El tamaño relativo de los huesos del tarso distal eran III + IV > I > II. Las longitudes comparativas de los huesos metatarsianos fueron III > II > IV > V > I. Los dígitos I y V fueron los más verticales y el dígito III fue el más horizontal. La falange proximal fue la de mayor tamaño.
Subject(s)
Animals , Elephants/anatomy & histology , Pelvic Bones/anatomy & histology , Hindlimb/anatomy & histologyABSTRACT
The Quaternary fossil record of Águas de Araxá (Q AA) is represented mainly by an accumulation of skeletal elements of several sizes, which are assigned to a population of Stegomastodon waringi. We analyzed 97 molars according to the ear stages of Sipson and Paula-Couto (1957), and developed a orphoetric ear index. The population structure (proportion of immature, subadult, adult, mature adult and senile adult individuals) was identified, and these five age classes were compared to those of extant elephant populations and defined with social implications. The analysis made possible to establish that the population is largely composed of adults: 14.89 percent are immature individuals, 23.04 percent subadults, 27.65 percent adults, 17.21 percent mature adults and another 17.21 percent senile adults. Based on population structure, we do not discard the possibility that the fossil population was stable or in recovery, and/or was experiencing a high-predation period on younger individuals. The number of individuals composing the past population studied here could suggest that the occupied environment was open due to comparisons to populations of extant elephants. We consider this population as an aggregation of family units, which suggests a time of low environmental humidity. Based on literature and our findings, their extinction appears to be regional and probably related to a catastrophic event.
O registro fossilífero do Quaternário de Águas de Araxá (QAA) é representado principalmente pelo acúmulo de restos dentários e de esqueleto de diversos tamanhos, atribuídos a uma população pretérita do mastodonte Stegomastodon waringi. Foram analisados 97 molares de acordo com os estágios de desgaste propostos por Simpson e Paula-Couto 1957, e desenvolveu-se um índice morfométrico de desgaste. A estrutura populacional (proporção entre indivíduos imaturos, subadultos, adultos, adultos maduros e adultos senis) foi identificada e comparada com populações de elefantes atuais. Foi possível estabelecer que esta população era amplamente composta por adultos: 14,89 por cento eram indivíduos imaturos; 23,04 por cento eram subadultos; 27,65 por cento eram adultos; 17,21 por cento eram adultos maduros e outros 17,21 por cento eram adultos senis. Baseados na estrutura populacional observada, não se descartou a possibilidade desta população estar estável ou em recuperação e/ou de ter passado por um período de predação dos indivíduos mais jovens. O número de indivíduos encontrados nesta população sugere que esta ocupava um ambiente aberto, de acordo com comparações com populações de elefantes atuais. Considerou-se a assembléia de mastodontes do Quaternário de Águas de Araxá como uma agregação de unidades familiares, o que sugere um momento de baixa umidade ambiental. Baseados em literatura e nos resultados encontrados, a sua extinção parece ser regional e possivelmente relacionada a um evento catastrófico.