Andrew Adogwa’s research while affiliated with University of the West Indies, St. Augustine and other places

The present study was taken to test the hypothesis that the medial nucleus of the trapezoid body (MNTB) of echolocating neotropical bats with different foraging behavior will exhibit morphological variations in relative size, degree of complexity and spatial distribution. The brains were collected from six male adult bats of each species: Noctilio leporinus (fish-eating), Phyllostomus hastatus (carnivorous/ omnivorous) and Carollia perspicillata (fruit-eating) and were double-embedded and transverse serial sections were cut and stained with cresyl fast violet. The results showed that the MNTB is well developed in all the bats in general and the mean length of the MNTB was 1160 ± 124 µm in N. leporinus, 400 ± 59 µm in P. hastatus and 320 ± 25µm in C. perspicillata. The body and brain weight do not reflect proportionately on the size of the MNTB in the present study. The hearing frequency spectrum did not covary with the size of the MNTB among the bats studied. The MNTB is clearly demarcated from the ventral nucleus of the trapezoid body (VNTB) only in P. hastatus. The MNTB comprised mainly three types of cells in all three bats: dense-staining multipolar cells (12.5 µm and 25.0 µm diameter); light-staining multipolar cells measuring (12.5 µm and 25.0 µm diameter) and light-staining round cells (5.0 µm diameter). The large sized MNTB was observed in N. leporinus, which suggests that it relies heavily on echolocation whereas P. hastatus and C. perspicillata use echolocation as well but also rely on hearing, smell and vision.

The morphology of the gastrointestinal tract (GI) is a strong indicator of the dietary habits of a species. The goal of this study was to describe the gross and microanatomy of the digestive tract of the neo‐tropical opossum (Didelphis marsupialis insularis) and relate them to the animals’ food habits. GI tracts from 12 adult animals were used for this study. Results found the small intestine made up 65.9% of the GI tract, and the stomach was simple with a prominent caecum. Histologically, the oesophageal mucosa was non‐keratinized and glands were found throughout the oesophagus. The large intestine showed a great number of goblet cells, the jejunum possessed well‐developed villi, and Peyer's patches were absent in the ileum. The absence of keratinization of the epithelial lining of the oesophagus and stomach and a high lymphocytic infiltration throughout the small and large intestine reflected a more carnivorous diet, whereas the presence of a well‐developed caecum in the large intestine indicated the ability to digest plant matter. Overall, the morphology of GI tract of D. m. insularis displayed both carnivorous and herbivorous features, allowing us to conclude that it is an omnivorous animal.

The understanding of the echolocation by studying different auditory nuclei of echolocating bats can be an important link in elucidating questions arising in relation to their foraging behavior. The superior olivary complex (SOC) is the primary center for processing the binaural cues used in sound localization since echo locating bats rely on acoustic cues to navigate and capture prey while in flight. The present study was taken to test the hypothesis that the SOC of echolocating neotropical bats with different foraging behavior will exhibit morphological variations in relative size, degree of complexity and spatial distribution. The brains were collected from six male adult bats of each species: Noctilio leporinus (fish eating), Phyllostomus hastatus (carnivorous/omnivorous) and Carollia perspicillata (fruit eating). They were double-embedded and transverse serial sections were cut and stained with cresyl fast violet. The SOC measured as 640 ± 70 µm in the N. leporinus bat, 480 ± 50 µm in the P. hastatus and 240 ± 30 µm in the C. perspicillata bat. The principal nuclei of the SOC of in all three bats were the LSO, MSO and MNTB. The MSO and LSO were very well developed in N. leporinus bats. The MSO of N. leporinus bat subdivided into DMSO and VMSO. The main cell type of cells present in MSO and LSO are dark staining multipolar cells in all the bats studied. The well-developed MSO and LSO of N. leporinus bats indicate that these bats are highly sensitive to low frequency sounds and interaural intensity differences, which help these bats to forage over water by using various types of echolocation signals. The average size of SOC in P. hastatus and C. perspicillata bats can be attributed to the fact that these bats use vision and smell along with echolocation to forage the food.

Abstract: The Cocrico (Oratalis ruficauda), one of the national birds of Trinidad and Tobago has drastically reduced in number in the recent years due to illegal hunting in Tobago. The captive rearing and breeding of these birds was in serious consideration as a part of the conservation programme. The understanding of the normal biology of this bird is essential to make better captive breeding and rearing policies. But, there is a dearth of published data related to, or describing, the detailed anatomy and histology of this bird apart from relating to commercial poultry. Therefore, the present study aimed to study the anatomy and histology of the digestive tract of the species, which in turn helps in developing suggestions for improvements in rearing, and to get a better understanding of its growth and production. Five apparently healthy adult birds (2 males and 3 females) were euthanized with the permission of the Forestry Division, Tobago House of Assembly (THA). The gross anatomical observations were made by dissection and the specimens were collected and fixed in 10% buffered formalin and processed by routine histological methods and stained with H&E and histological observations were made. The esophagus extended from the pharynx to the proventriculus with an average length of 14.1 cm and dilated at the thoracic inlet to form a crop with average breadth of 2.92 cms. The mucosa lined by stratified squamous epithelium with non-keratinized type with series of tubular mucous glands. The tunica muscularis consisted of inner and outer layer of smooth muscles. The stomach made up of a proventriculus and gizzard with a narrow isthmus between them. The proventriculus was spindle-shaped and measured an average length of 2.63 cm whereas ventriculus was lens-shaped and measured an average of 3.10 cm. The mucosa of proventriculus was extensively folded with simple tubular glands whereas the gizzard presented low folds with branched glands. The intestines consisted small intestines (duodenum, jejunum and ileum), paired ceca and small colorectum, which contributed 70.7% of the digestive tract length. The villi were well developed in duodenum and decline in number in jejunum and ileum. The anatomy and histology of the digestive tract of the cocrico showed several similarities with chicken but notable differences like poorly developed crop, the absence of an esophageal tonsil, a relatively thin gizzard, under-developed caeca and the absence of caecal tonsils. Keywords: Process simulation, energy analysis, carbon dioxide removal, ammonia process

This review focuses on the information that is available on the reproductive biology of Didelphis. From the findings of over 60 scientific documents - beginning as early as 1704- it was found that opossums possess some very exclusive reproductive adaptations, including: short gestation period, paired spermatozoa and a temporary pseudo-vaginal canal. These findings, however, were based on investigation on one or two species of the genus only. An overall picture of the reproductive biology and any adaptations or differences between the six species in the genus was therefore not possible. In conclusion, many gaps remain and novel theories on the topic have yet to be proposed on tropical and neo-tropical opossum species. Therefore, further study into the reproductive biology of South American and Caribbean species is highly recommended. This will allow for a clearer understanding of the reproductive biology of this marsupial, which can be a guide in the development of an intensive animal production system in the tropics.

The present study was aimed to document the anatomy of the hind limb skeleton from a structural and functional perspective for the better understanding of locomotor behavior of the orange rumped agouti (Dasyprocta leporina), a caviomorph rodent on the verge of domestication in Trinidad and Tobago. The study was carried out by collecting bones from 6 adult male and 6 adult female animals. The results showed that several features were indicative of emphasized parasagittal movements and stabilized joints. The well-developed ischial tuber, long and strongly built ilium with wide wing and close grouping of greater and lesser trochanter near the proximal tuberosity of the Original Research Article Venkatesan et al.; ARRB, 12(2): 1-12, 2017; Article no.ARRB.30949 2 femur imply that the animal possesses a well developed flexor-extensor muscle set adapted to quick movements (reaction). The rather elongated body of the calcaneus strengthened the good jumping ability of D. leporina. These features along with elongation of the shank and foot indicate that D. leporina exhibits a well-developed cursorial ability with high jumping potential.

The aim of the study is to document the morphological details of the forelimb bones of the orange rumped agouti (Dasyprocta leporina). The bones were collected from 12 adult animals of both sexes. Each limb comprised of 47 bones (30 bones, 17 sesamoid bones). The clavicle was poorly developed while the metacromion process of the scapula was very well developed. The humerus was peculiar, displaying poorly developed deltoid tuberosity, teres tubercle and the crest of the humerus and complete absence of the musculospiral groove. The distal extremity of the humerus was wide and presented a well-developed lateral epicondyle. The radius and ulna were separated and the ulna was larger and longer. The radial tuberosity was absent and semilunar notch of the ulna was deeper. The proximal row of carpals comprised of only two bones viz., radio-intermediate and ulnar carpal along two sesamoid bones viz., radial and accessory sesamoid bones on the palmar face. The manus presented five long, relatively thin metacarpal bones and five digits. The first digit was shorter with two phalanges whereas the other digits presented three phalanges. In conclusion, the features in the forelimb bones of the D. leporina reflected a wide functional spectrum, which include fast running, digging and shoveling. However, predominant features of the forelimb typified the D. leporina as cursorial rodents. (

This study investigated the gross and microscopic anatomy of the reproductive tract of five cage reared female agouti (Dasyprocta leporina). The ovaries were paired yellow ovoid bodies with a mean (± SD) length of 10 mm (± 2.1), held near the caudal pole of the kidneys. The ovarian cortex consisted of cellular connective tissue in which ovarian follicles were embedded. Highly vascularized tissue was noted in the ovarian medulla. The fallopian tubes increased in width caudally from the ovary to the uterus. Paired uterine horns converged to form the Y-shaped uterine body and the characteristic duplex uterus was separated by a septum. The cervix was found at the pelvic inlet and protruded into the proximal vaginal lumen as the fornix. The vagina had a mean (± SD) length of 7 cm (± 11.4), representing the longest portion of the reproductive tract. Differences in vaginal epithelium were evident, indicating that vaginal colpocytology may be used to evaluate the reproductive stage of the female agouti in captivity. The distance between the urethral aperture and the anus may be used to determine the sex of cage reared agouti, especially when the perineum seals the vaginal orifice. Keywords: Anatomy; Dasyprocta; Female Agouti; Histology; Reproduction

This study investigated the gross and microscopic anatomy of the reproductive tract of five cage reared female agouti (Dasyprocta leporina). The ovaries were paired yellow ovoid bodies with a mean (± SD) length of 10 mm (± 2.1), held near the caudal pole of the kidneys. The ovarian cortex consisted of cellular connective tissue in which ovarian follicles were embedded. Highly vascularized tissue was noted in the ovarian medulla. The fallopian tubes increased in width caudally from the ovary to the uterus. Paired uterine horns converged to form the Y-shaped uterine body and the characteristic duplex uterus was separated by a septum. The cervix was found at the pelvic inlet and protruded into the proximal vaginal lumen as the fornix. The vagina had a mean (± SD) length of 7 cm (± 11.4), representing the longest portion of the reproductive tract. Differences in vaginal epithelium were evident, indicating that vaginal colpocytology may be used to evaluate the reproductive stage of the female agouti in captivity. The distance between the urethral aperture and the anus may be used to determine the sex of cage reared agouti, especially when the perineum seals the vaginal orifice.

The aim of the present study is to document cytoarchitectural details of Medial Geniculate Body (MGB) of the brain in three species of echolocating bats with different forage behavior. The brains were collected from six male adult bats of each species: Noctilio leporinus (fish-eating), Phyllostomus hastatus (carnivorous/ omnivorous) and Carollia perspicillata (fruit-eating) and were double-embedded and transverse serial sections were cut and stained with cresyl fast violet. The results showed that the mean length of the medial geniculate body was 1330 ± 115 µm in N. leporinus, 1210 ± 90 µm in P.hastatus and 790 ± 68 µm in C. perspicillata. The MGB of all three bats appeared to be divided into three divisions: dorsal (MGBd), ventral (MGBv) and medial (MGBm). These divisions were most distinct in the N. leporinus bat and least apparent in the C. perspicillata. In the N. leporinus, both dense-staining multipolar cells and light-staining round cells were located throughout the MGB. In the P. hastatus, the dense-staining multipolar cells were predominantly present in the ventral division of the middle third of the MGB, whereas light- staining round cells predominated at the rostral end of the MGB. Only light-staining round cells were seen throughout the MGB of the C. perspicillata. The large sized MGB and its clear subdivisions in N. leporinus suggests that it relies heavily on echolocation whereas P.hastatus and C. perspicillata use echolocation as well but also rely on hearing, smell and vision