Skip to main content

Research Repository

Advanced Search

Morphological and cytochemical characteristics of Varanus niloticus (Squamata, Varanidae) blood cells

Soliman, Soha A.; Abd-Elhafeez, Hanan H.; Mohamed, Nor-Elhoda; Al-Rashdi, Barakat M; Alghamdi, Abdullah A.A.; Elmansi, Ahmed; Salah, Abdallah S; El-Gendy, Samir A.A.; Rutland, Catrin S.; Massoud, Diaa

Morphological and cytochemical characteristics of            Varanus niloticus            (Squamata, Varanidae) blood cells Thumbnail


Soha A. Soliman

Hanan H. Abd-Elhafeez

Nor-Elhoda Mohamed

Barakat M Al-Rashdi

Abdullah A.A. Alghamdi

Ahmed Elmansi

Abdallah S Salah

Samir A.A. El-Gendy

Diaa Massoud


Varanus niloticus is a lizard residing within the Varanidae family. To date no studies detailing its blood morphology and characteristics have been conducted. This study used histologically stained blood and bone marrow samples to visualize the cells and their characteristics. The erythrocytes were nucleated, these nuclei were located in the middle of the elliptical cells. Hemoglobin filled the erythrocyte cytoplasm. Eosinophils were large cells with lobed nuclei and spherical acidophilic granules. Large granulocytes called heterophils were present and characterized by their fusiform/pleomorphic cytoplasmic granules. Small spherical granulocytes, known as basophils, presented with round, deeply stained metachromatic granules that gave the cytoplasm a dusty or cobblestoned appearance which was able to cover the nucleus, which in turn had an unusual shape. Thrombocytes ranged in shape from ellipsoidal to fusiform. They featured an elliptical, centrally located nucleus and a pale cytoplasm, with small vacuoles, and fine acidophilic granulation. The smallest variety of non-granular leukocytes was the lymphocytes. Their cytoplasm was sparse, finely granular, light blue, had tiny cytoplasmic projections, featuring a high nucleus: cytoplasm ratio. Larger and smaller sized populations of lymphocytes were distinguished, with the larger cells similar in size to azurophils. In general, the pleomorphic monocytes were the biggest mononuclear leucocytes, displaying cytoplasmic projections. Their nuclei were ovoid, kidney- or bean-shaped, with vacuolated and granular cytoplasms. Round cells were common among the monocytic azurophils, and they had a granular cytoplasm, and their nuclei were typically eccentric. The present research identifies the cell types and morphologies within the Varanus niloticus. Highlights: H&E, PAS, toluidine blue, methylene blue, and Safranin O stains provided morphological and morphometric descriptions of Varanus niloticus blood cells from blood smears and bone marrow. The Varanus niloticus had nucleated erythrocytes and white blood cells, mostly granulocytes (heterophils, eosinophils, and basophils) and mononuclear cells (azurophils, lymphocytes, and monocytes). Aquatic vertebrate Varanus niloticus had larger erythrocytes than terrestrial counterparts. Blood cell morphological and cytochemical features were similar to other reptilian species, with some species-specific differences, which likely accommodate differing environmental conditions. These results may help clinical researchers track the pathological conditions and support conservation of these wild animals.


Soliman, S. A., Abd-Elhafeez, H. H., Mohamed, N., Al-Rashdi, B. M., Alghamdi, A. A., Elmansi, A., …Massoud, D. (2023). Morphological and cytochemical characteristics of Varanus niloticus (Squamata, Varanidae) blood cells. Microscopy Research and Technique, 86(5), 600-613.

Journal Article Type Article
Acceptance Date Jan 17, 2023
Online Publication Date Feb 1, 2023
Publication Date 2023-05
Deposit Date Jan 19, 2023
Publicly Available Date Feb 1, 2023
Journal Microscopy Research and Technique
Print ISSN 1059-910X
Electronic ISSN 1097-0029
Peer Reviewed Peer Reviewed
Volume 86
Issue 5
Pages 600-613
Keywords Blood Cells, Blood smear, Varanus niloticus, Histochemical stains, Morphological and morphometric characteristics
Public URL
Publisher URL


You might also like

Downloadable Citations