A quantitative approach to the cranial ontogeny of Lycalopex culpaeus (Carnivora: Canidae)

Abstract

The study of cranial ontogeny is important for understanding the relationship between form and function in developmental, ecological, and evolutionary contexts. The transition from lactation to the diet of adult carnivores must be accompanied by pronounced modiWcations in skull morphology and feeding behavior. Our goal was to study relative growth and development in the skull ontogeny of the canid Lycalopex culpaeus, and interpret our Wndings in a functional context, thereby exploring the relationship between changes in shape and size with dietary habits and age stages. We performed quantitative analyses, including multivariate allometry and geometric morphometrics. Our results indicate that shape changes are related to functional improvements of the jaw mechanics related for food catching/processing. Estimates of full muscle size, mechanical advantage, and adult cranial shape are reached after sexual maturity, while adult mandible and skull size are reached after weaning, which is related to diet change (incorporation of meat and other food items). The ontogenetic pattern observed in L. culpaeus is similar to those observed in Canis familiaris and C. latrans. However, the magnitude of change seen in L. culpaeus is smaller than those seen in the felid Puma concolor and considerably smaller than those seen in the bone cracker hyaenid Crocuta crocuta. These patterns are associated with dietary habits and specializations in skull anatomy, as L. culpaeus, domestic dog and coyote are generalist species compared with hypercarnivores such as C. crocuta and P. concolor.

Three-dimensional cranial ontogeny in pantherines (Panthera leo,P. onca,P. pardus,P. tigris; Carnivora:, Felidae)

“…P. leo and P. onca reached definitive cranial shape and size at the same age class, and P. onca reached the final cranial shape before to cranial size. This pattern was previously observed in felids, such as Herpailurus yagouaroundi and Puma concolor (Segura et al, 2013), and is clearly opposite to the pattern of P. pardus and canids, such as L. culpaeus, which obtained definitive cranial size before obtaining final cranial shape (Segura & Prevosti, 2012) (Fig. 10).…”

“…10, see Segura et al, 2013); this pattern is shared with the canids Lycalopex culpaeus (Molina, 1782) (Fig. 10, see Segura & Prevosti, 2012) and Canis latrans Say, 1823 (La Croix et al, 2011). P. leo and P. onca reached definitive cranial shape and size at the same age class, and P. onca reached the final cranial shape before to cranial size.…”

“…Tanner et al, 2010;Segura & Prevosti, 2012), by calculating Procrustes distance (PD) as the square root of the sum of the squared distances between each landmark of one specimen and the mean configuration of the smallest age class. In addition, Centroid size (CS) was used as an estimate of cranial size (Bookstein, 1991; Zelditch et al, Figure 2.…”

Cranial ontogeny in the Puma lineage,Puma concolor,Herpailurus yagouaroundi, andAcinonyx jubatus(Carnivora: Felidae): a three-dimensional geometric morphometric approach

“…A similar trend was previously detected in species studied with different methods (e.g. P. concolor , Segura & Flores, ; Giannini et al ., ; Lycalopex culpaeus , Segura & Prevosti, ; Segura, ; Canis latrans , La Croix et al ., 2011a, b; Crocuta crocuta , Tanner et al ., ). Using sexual maturity as a landmark to compare these species (Fig.…”

“…We analysed a sample of 336 specimens representing the three living species of the Puma lineage: P. concolor ( N = 110); H. yagouaroundi ( N = 147); and A. jubatus ( N = 79). The sample includes both juveniles and adults from different age stages, estimated by dental formulae and tooth wear, following a modified version of the classification described by Segura & Prevosti () (Table ). Our sample included the following juveniles (numbers indicate females, males, and unsexed specimens, respectively) – P. concolor , B, 2/0/0; J1, 1/2/5; J2, 0/0/2; J3, 1/0/2; J4, 0/0/3; H. yagouaroundi , B, 0/0/1; J1, 4/3/4; J2, 2/0/3; J3, 6/3/2; J4, 3/2/2; A. jubatus , B, 0/0/0; J1, 1/1/1; J2, 1/1/0; J3, 1/1/0; J4, 0/1/1 – and the following adults – P. concolor , A1, 7/7/22; A2, 4/5/31; A3, 2/2/12; H. yagouaroundi , A1, 13/22/18; A2, 17/12/18; A3, 1/3/8; A. jubatus , A1, 9/14/11; A2, 14/9/11; A3, 1/1/0.…”