While the elegant Anglican hymn All things bright and beautiful may praise “all creatures great and small,” and speak of their equality in the eyes of an Almighty, we know that certain animals are a tad more special than others. And those animals are us (sorry, dog lovers, cat cuddlers, and you whale-types). Humans and our kin—the rest of the order Primates (the “firsts” as so anointed by Linnaeus in 1758)—are “kings” of the proverbial hill. Yes, bees may have grammar and Moby Dick can carry a grudge, but for good or ill, that face we see in the mirror each morning is a member of our planet's dominant tribe.
Humans may have claimed the seat at the head of our primate table, but our relatives can be mighty close, both anatomically and genetically. Uncovering and assessing the relationship of humans to the other primates and placing this in an evolutionary context, has been the prime directive for a host of comparative anatomists, primatologists, anthropologists, evolutionary morphologists, and geneticists to name but some that have explored the questions. This fascination—almost compulsion—to understand our ilk has been well represented within the pages of The Anatomical Record throughout its history. Indeed special issues of this journal, such as those on primate special senses (Smith et al, 2004; Dominy et al., 2004; Laitman 2004) or the functional anatomy of primates (Organ et al., 2010; Laitman, 2010; Laitman and Albertine, 2010) have displayed state-of-the-art explorations into the world of our relatives.
In keeping with that robust tradition of exploring our closest relatives is this special issue, “Evolutionary and Functional Morphology of New World Monkeys,” Guest edited by Rosenberger (2011); Laitman (2011). Rosenberger et al. now put their collective lenses upon the world of arguably the least know cadre of monkeys, those from the western hemisphere, the “New World,” in colloquial terms.
While New World monkeys (NWM) are not as well represented in anatomical studies in general as their Old World counterparts (e.g., macaques, baboons, apes) have been, many have been the focus of both comparative and specific examination. Indeed, our journal has been the home for two types of studies on NWM: 1) those that have examined some species within a broader context of primates and 2) those that have focused upon NWM themselves.
Comparative studies—with significant focus on our NWM brethren—can be found in the research by some of the “greats” in comparative anatomy, such as those by Wingate Todd on the thoracolumbar vertebrae of mammals (1922); Schultz on the comparative weight of the testes in primates (1943); and William Straus on the primate subarcuate fossa (1960). Examples of more recent assessments that include NWM can be found in the elegant anatomical and histological examination of the vomero-nasal organ by Smith and colleagues (Smith et al., 2001, 2002); the work by Ryan and Walker (2010) on trabecular bone structure in humeral and femoral heads among primates; and the comparative observations by Vinyard and Taylor (2010) on jaw-muscle architecture and chewing.
Examples of studies that specifically addressed NWM anatomy include: those by the great anatomist George B. Wislocki on uterine bleeding in Ateles (Goodman and Wislocki, 1935) and the chorionic villi and placenta across platyrrhines (Wislocki, 1943); a study on the endometrium of NWM by Kaiser (1947); Smith et al. (2005) examination of the process of maxillary pneumatization in callitrichids; and Organ's studies on the caudal musculature in prehensile and non-prehensile tails of platyrrhines (Organ et al., 2009) and on platyrrhine caudal vertebrae (Organ, 2010).
This month's special issue of The Anatomical Record continues our tradition of exploring our primate relatives, both examining species and structures poorly understood, but now placing this within the context of evolutionary change. Many of the mysteries surrounding our New World monkey relatives will be unveiled within the pages of this fascinating issue.