Boy, S.C. and G. Steenkamp (2004). Neural innervation of the tusk pulp of the African elephant (Loxodonta africana). Veterinary Record 154(12): 372-374. ISSN: 0042-4900.
NAL Call Number: 41.8 V641
Descriptors: tooth pulp, Loxodonta africana, innervation, autonomic nervous system, peripheral nerves, histology, pain, animal welfare.
Debruyne, R. (2004). Apports de la phylogenie moleculaire et de la morphometrie a la systematique des elephants d'Afrique. [Contribution of molecular phylogeny and morphometrics to the systematics of African elephants]. Journal De La Societe De
Biologie 198(4): 335-42.
NAL Call Number: QH301.S6
Abstract: African elephants are conventionally classified as a
single species: Loxodonta africana (Blumenbach 1797). However, the
discovery in 1900 of a smaller form of the African elephant, spread
throughout the equatorial belt of this lan d, has given rise to a debate
over the relevance of a second species of elephant in Africa. The
twentieth century has not provided any definite answer to this question.
Actually, recent molecular analyses have sustained this issue by
advocating either a d ivision of forest elephants into a valid species, or
their inclusion as a subspecies of L. africana. Our work initiated
at the National Museum of Natural History of Paris provides new molecular
(mitochondrial) and morphological (and morphometrical)
evidence making it possible to propose a comprehensive phylogenetic
hypothesis. It appears that there is no conclusive argument to keep forest
elephants (cyclotis form) and savannah elephants (africana form) apart in
two distinct species. A high level of
mitochondrial introgression between the two forms, as well as a continuum
in the morphology of the skulls of the two morphotypes rather suggests
that, despite an ancient division, these two taxa freely interbreed
wherever their ranges intersect. We thus adopt a conservative systematic
position in considering these two forms as two subspecies, respectively:
L. africana africana, the savannah elephant, and L. africana
cyclotis, the forest elephant. We finally discuss the conservation
topic in
the light of this systematic framework.
Descriptors: classification, genetics, molecular evolution, phylogeny, Africa, body size, mitochondrial DNA genetics, anatomy and histology, museums, skull anatomy and histology.
Language of Text: French.
Goebbel, L., M.S. Fischer, T.D. Smith, J.R. Wible, and K.P. Bhatnagar (2004). The vomeronasal organ and associated structures of the fetal African elephant, Loxodonta africana (Proboscidea, Elephantidae). Acta Zoologica 85(1): 41-52.
ISSN: 0001-7272.
NAL Call Number: 410 AC8
Descriptors: sense organs development, vomeronasal organ, fetal African elephant, associated structures, adult vomernasal-nasopalatine duct system.
Hakeem, A.Y., P.R. Hof, C.C. Sherwood, R.C. Switzer III, L.E. Rasmussen, and J.M. Allman (2005). Brain of the African elephant (Loxodonta africana): neuroanatomy from magnetic resonance images. Anatomical Record. Part A, Discoveries in
Molecular, Cellular, and Evolutionary Biology 287(1): 1117-27.
NAL Call Number: QL801.A53
Descriptors: brain anatomy and histology, anatomy and histology, magnetic resonance imaging, brain chemistry, brain mapping, neuroanatomy.
Hatfield, J.R., D.A. Samuelson, P.A. Lewis, and M. Chisholm (2003). Structure and presumptive function of the iridocorneal angle of the West Indian manatee (Trichechus manatus), short-finned pilot whale (Globicephala macrorhynchus),
hippopotamus
(Hippopotamus amphibius), and African elephant (Loxodonta africana). Veterinary Ophthalmology 6(1): 35-43.
Abstract: The iridocorneal angles of prepared eyes from the West
Indian manatee, short-finned pilot whale, hippopotamus and African
elephant were examined and compared using light microscopy. The manatee
and pilot whale demonstrated capacity for a
large amount of aqueous outflow, probably as part of a system
compensating for lack of ciliary musculature, and possibly also related to
environmental changes associated with life at varying depths. The elephant
angle displayed many characteristics of large herbivores, but was found to
have relatively low capacity for aqueous outflow via both primary and
secondary routes. The hippopotamus shared characteristics with both land-
and water-dwelling mammals; uveoscleral aqueous outflow may be substantial
as in the marine mammals, but the angular aqueous plexus was less
extensive and a robust pectinate ligament was present. The angles varied
greatly in size and composition among the four species, and most
structures were found to be uniquely suited to the habitat of each
animal.
Descriptors: cornea anatomy and histology, cornea physiology, mammals anatomy and histology, mammals physiology, aqueous humor physiology, Artiodactyla anatomy and histology, Artiodactyla physiology, elephant anatomy and histology, elephant
physiology, species specificity, Trichechus manatus anatomy and histology, Trichechus manatus physiology, whale anatomy and histology, whale physiology.
Weissengruber, G.E., M. Egerbacher, and G. Forstenpointner (2005). Structure and innervation of the tusk pulp in the African elephant (Loxodonta africana). Journal of Anatomy 206(4): 387-93.
NAL Call Number: 447.8 J826
Abstract: African elephants (Loxodonta africana) use their
tusks for digging, carrying and behavioural display. Their healing ability
following traumatic injury is enormous. Pain experience caused by dentin
or pulp damage of tusks seems to be negligible in elephants. In this study
we examined the pulp tissue and the nerve distribution using histology,
electron microscopy and immunhistochemistry. The results demonstrate that
the pulp comprises two differently structured regions. Randomly
orientated
collagen fibres characterize a cone-like part lying rostral to the
foramen apicis dentis. Numerous nerve fibres and Ruffini endings are found
within this cone. Rostral to the cone, delicate collagen fibres and large
vessels are orientated longitud inally. The rostral two-thirds of the pulp
are highly vascularized, whereas nerve fibres are sparse. Vessel and nerve
fibre distribution and the structure of connective tissue possibly play
important roles in healing and in the obviously limited pain expe rience
after tusk injuries and pulp alteration. The presence of Ruffini endings
is most likely related to the use of tusks as tools.
Descriptors: dental pulp anatomy and histology, tooth anatomy and histology, Africa, biological markers analysis, dental pulp innervation, immunohistochemistry methods, nerve fibers ultrastructure, staining and labeling.
Weissengruber, G.E. and G. Forstenpointner (2004). Musculature of the crus and pes of the African elephant (Loxodonta africana): insight into semiplantigrade limb architecture. Anatomy and Embryology 208(6): 451-61.
Abstract: The limbs of elephants are designed to support the weight
of the largest terrestrial animal, and they display unique morphological
peculiarities among mammals. In this article we provide a new and detailed
anatomical description of the m uscles of the lower hindlimb in African
elephants (Loxodonta africana), and we place our observations into
a comparative anatomical as well as a functional morphological context. At
the cranial aspect of the shank (crus) and the foot (pes), the fle xors of
the tarsal joint and the extensors of the toes form a flat muscular plate
covering the skeletal elements. Caudal to the tibia and the fibula the
Musculus (M.) soleus is strongly developed, whereas the M. gastrocnemius
and the M. flexor digitorum s uperficialis are thin. Small flexors,
adductors, and abductors of the toes are present. The M. tibialis caudalis
as well as the Mm. fibularis longus and brevis mainly support the tarsal
joint. The design of the muscular structures matches the specific
requirements of heavy-weight bearing as well as of proboscidean limb posture
and locomotion patterns.
Descriptors: foot anatomy and histology, hindlimb anatomy and histology, lower extremity anatomy and histology, muscle, skeletal anatomy and histology, foot physiology, hindlimb physiology, lower extremity physiology, muscle, skeletal physiology,
weight bearing physiology.
Weissengruber, G. E, F. Fuss K, G. Egger, G. Stanek, K. Hittmair M, and G. Forstenpointner (2006). The elephant knee joint: morphological and biomechanical considerations. Journal of Anatomy 208(1): 59-72.
NAL Call Number: 447.8 J826
Abstract: Elephant limbs display unique morphological features which are related mainly to supporting the enormous body weight of the animal. In elephants, the knee joint plays important roles in weight bearing and locomotion, but anatomical data
are sparse and lacking in functional analyses. In addition, the knee joint is affected frequently by arthrosis. Here we examined structures of the knee joint by means of standard anatomical techniques in eight African (Loxodonta africana) and three
Asian elephants (Elephas maximus). Furthermore, we performed radiography in five African and two Asian elephants and magnetic resonance imaging (MRI) in one African elephant. Macerated bones of 11 individuals (four African, seven Asian elephants)
were measured with a pair of callipers to give standardized measurements of the articular parts. In one Asian and three African elephants, kinematic and functional analyses were carried out using a digitizer and according to the helical axis concept. Some
peculiarities of healthy and arthrotic knee joints of elephants were compared with human knees. In contrast to those of other quadruped mammals, the knee joint of elephants displays an extended resting position. The femorotibial joint of elephants shows
a high grade of congruency and the menisci are extremely narrow and thin. The four-bar mechanism of the cruciate ligaments exists also in the elephant. The main motion of the knee joint is extension-flexion with a range of motion of 142 degrees . In
elephants,
arthrotic alterations of the knee joint can lead to injury or loss of the cranial (anterior) cruciate ligament.
Descriptors: knee joint, anatomy, morphological, biomechanical, weight bearing, locomotion, radiography, MRI, magnetic resonance imaging, arthrosis.
Weissengruber, G.E. and G. Forstenpointner (2004). Shock absorbers and more: design principles of the lower hindlimb in African elephants (Loxodonta africana). Journal of Morphology 260(3): 339. ISSN: 0362-2525.
NAL Call Number: 444.8 J826
Descriptors: African elephants, lower hindlimb, design principles, shock absorbers, locomotion, anatomy.
West, J.B., Z. Fu, A.P. Gaeth, and R.V. Short (2003). Fetal lung development in the elephant reflects the adaptations required for snorkeling in adult life. Respiratory Physiology and Neurobiology 138(2-3): 325-33.
NAL Call Number: QP121.A1R4
Abstract: The adult elephant is unique among mammals in that the pleural membranes are thickened and the pleural cavity is obliterated by connective tissue. It has been suggested that this peculiar anatomy developed because the animal can snorkel
at depth, and this behavior subjects the microvessels in the parietal pleura to a very large transmural pressure. To investigate the development of the parietal pleura, the thickness of the endothoracic fascia (ET) was measured in four fetal African
elephants
of approximate gestational age 111-130 days, and the appearances were compared with those in human, rabbit, rat and mouse fetuses of approximately the same stage of lung organogenesis. The mean thicknesses of ET in the elephant, human, rabbit, rat
and
mouse were 403, 53, 29, 27 and 37 microm, respectively. This very early development of a thick parietal pleura in the elephant fetus is consistent with the hypothesis of a long history of snorkeling in the elephant's putative aquatic ancestors.
Descriptors: adaptation, biological physiology, embryonic and fetal development, lung embryology, pleura embryology, fetus, gestational age, intercostal muscles, lung anatomy and histology, mice, pleura anatomy and histology, rabbits, rats,
species specificity.