An investigation of ecological correlates with hand and foot morphology in callitrichid primates

Abstract

Studies of primate taxomony and phylogeny often depend on comparisons of limb dimensions, yet there is little information on how morphology correlates and contributes to foraging strategies and ecology. Callitrichid primates are ideal for comparative studies as they exhibit a range of body size, limb proportions and diet. Many callitrichid species exhibit a high degree of exudativory and to efficiently exploit these resources they are assumed to have evolved morphologies that reflect a level of dependence on these resources. We tested assumptions by considering measurements of limb proportion and frictional features of the volar surfaces in preserved specimens of 25 species with relation to published life history and ecological data.The degree of exudativory and utilization of vertical substrates during foraging were found to correlate both with size and with size-corrected foot and hand dimensions. Smaller species, which engage in greater degrees of exudativory, had proportionally longer hands and feet and more curved claw-like tegulae (nails) on their digits to facilitate climbing on vertical substrates.The density of patterned ridges (dermatoglyphs) on the volar surfaces of the hands and feet is higher in more exudativorous genera, suggesting a role in climbing on vertical tree trunks during foraging. Dermatoglyph comparisons suggest that ridges on the soles and palms may facilitate food procurement by enhancing frictional grip during exudate feeding. Volar pad features corroborate taxonomic relationships described from dental morphology. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Callitrichidae (Mammalia: Primates) includes over forty diverse species of New World Monkey. These may be grouped into 'marmosets' (Callibella, Callimico, Callithrix, Cebuella, and Mico) or tamarins (Leontopithecus and Saguinus) (Rylands et al., 2012). Prior to the reassessment of taxonomic relationships by Rylands et al., (2000) and the subsequent recognition of Callibella as a separate species (Van Roosmalen and Van Roosmalen, 2003), Callithrix was the most diverse genus, with over twenty species. Since 2003 Callibella, Callimico and Cebuella have been considered monotypic and fourteen species have been removed from Callithrix to a new genus Mico, thereby making Saguinus the most diverse callitrichid genus (Rylands et al., 2012). Recent analysis of phylogenetic relationships in all primates (Perelman et al. 2011) further confirms the taxonomy described in Cortés-Ortiz (2009): (Saguinus (Leontopithecus (Callimico (Callithrix (Callibella (Cebuella/Mico)))))).Although their taxonomy is under seemingly constant review, callitrichids are ideal subjects to investigate morphology and allometry trends in relation to ecology because they represent a wide range of body sizes and exhibit variability in diet and foraging strategies both between a...

Effects of support diameter and compliance on common marmoset (Callithrix jacchus) gait kinematics

“…Marmosets are small-bodied Neotropical monkeys and committed arboreal quadrupeds (Stevenson and Rylands, 1988;Garber, 1992;Rylands and de Faria, 1993;Souto et al, 2007). Through adaptation to facilitate gumnivory on large vertical tree trunks, marmosets have become quite derived relative to other primates (Lacher et al, 1984;Sussman and Kinzey, 1984;Garber, 1992;Hamrick, 1998;Vinyard et al, 2009;Young, 2009;Smith and Smith, 2013). In contrast to most other extant primates, marmosets have claw-like tegulae, rather than flat nails, on all digits except the hallux, and have a relatively short, adducted hallux with diminished intrinsic musculature (Beattie, 1927;Midlo, 1934;Szalay and Dagosto, 1988;Hamrick, 1998).…”

Angular momentum and arboreal stability in common marmosets (Callithrixjacchus)

“…We test these predictions by examining the gait dynamics of common marmosets moving over broad and narrow diameter supports (i.e., elevated poles). Although, through adaptation to gumnivory, marmosets have become quite derived relative to other primates (Sussman and Kinzey, ; Garber, ; Hamrick, ; Young, ; Smith and Smith, ), as small‐bodied arboreal quadrupeds with claw‐like tegulae on all digits except the hallux, marmosets, and other callitrichids have converged on the general morphotype thought to characterize the early stages of euprimate evolution (Szalay and Dagosto, ; Gebo, ; Bloch et al, ; Sargis et al, ). As such, empirical data on marmoset arboreal stability can serve as a baseline against which to evaluate balance performance in other, less‐derived primates that adhere more closely to the crown primate bauplan (e.g., an animal with fully developed grasping extremities).…”

Tail function during arboreal quadrupedalism in squirrel monkeys (Saimiri boliviensis) and tamarins (Saguinus oedipus)

“…Squirrel monkeys are primarily insectivorous, typically moving on small branches, twigs, and vines during foraging (i.e., substrates <5 cm in diameter: Fleagle et al, ; Boinski, ). In contrast, like all callitrichines, tamarins are specialized for exudativorous foraging, though they also exploit a variety of resources beyond tree exudates, including fruits and insects (Sussman and Kinzey, ; Vinyard et al, ; Smith and Smith, ). In association with exudativory, tamarins most often travel on large branches and boughs (i.e., 6–10 cm in diameter), though they also exploit relatively small diameter supports (i.e., <1.5 cm) during other feeding activities (Garber, , ; Garber and Sussman, ; Sussman and Kinzey, ; Garber, ; Nyakatura and Heymann, ; Smith and Smith, ).…”