Individual identifcation of armadillos (Mammalia, Cingulata) using a photo‑identifcation software

GALLO, JORGE ALBERTO; AGUSTÍN M. ABBA; MARIELLA SUPERINA

MAMMALIAN BIOLOGY

ELSEVIER GMBH

Año: 2022

1616-5047

The scales of the head shield of armadillos form a distinctive pattern which facilitates a reliable identifcation of individuals.Comparing images of head shields of diferent individuals by eye is, however, time-consuming, especially when working withlarge catalogues of photographed animals. Computer-assisted matching of photographs calculates similarity scores betweenimages, thus allowing to limit the visual comparisons to those individuals having the highest scores. The aim of our study wasto identify individual patterns of scales on the head shield of ten armadillo species, and test a photo-identifcation softwarein identifying individuals based on their head shield pattern. We analyzed 354 frontal photographs of the head shield of 10species of armadillos taken from diferent sources. Of those pictures, 153 were diferent photographs of the same animals.At frst, all photographs were compared by eye. Then, we used the pattern extraction and matching software Wild-ID tocompare images and fnd possible matches. None of the individuals on the images were misidentifed as other individuals (nofalse acceptance errors), but the software falsely rejected 26 images. While the most common factors afecting the computerassisted matching process were the refection of a fash-light (when fash photography was used) and exposure issues, thefash refection occurs only when photographing museum collections and is unlikely to afect feld photographic surveysunless fash is used in specifc conditions, such as for nocturnal armadillos. Our results suggest that the software Wild-ID isa useful tool to individually identify armadillos for capture-recapture studies, including long-term studies.