Hematological parameters of a Neotropical wild frog population, with a phylogenetic perspective on blood cell composition in Anura.

Hematological parameters can provide key information to an animal health status. However, this information is usually hard to obtain. Here, we described the hematological parameters of Leptodactylus podicipinus in the Brazilian Pantanal. We measured red blood cell morphometrics, erythrogram, and leukogram. We also tested for phylogenetic signal in the erythrogram and leukogram of 48 frog species from 15 families, testing if body size explains their variation. Lymphocytes were the most abundant leukocytes (>60%) in L. podicipinus, followed by neutrophils (∼10%). Given that L. podicipinus is an abundant and widely distributed species in central Brazil, knowing its hematological pattern can help establish a baseline and improve its use as a bioindicator of environmental degradation. Mean corpuscular hemoglobin and value contributed more to the phylomorphospace of erythrogram, in which Leptodactylus spp. and Hypsiboas raniceps had lower values of these variables, whereas Bufotes viridis and Hyla arborea had high values. The phylogenetic signal was spread throughout the dimensions of the leukogram phylomorphospace. The variables that most contributed to it were total leukocytes counts, lymphocytes, and neutrophils. We also found a moderate phylogenetic signal for both the erythrogram and leukogram. Accordingly, body size accounted for a low proportion of variation in both the leukogram (4.7%) and erythrogram (0.57%). By applying phylogenetic comparative methods to hematological parameters, our results add a new perspective on the evolution of blood cell physiology in frogs.