Taxonomic status of Tamarinus imperator subgrisescens (Lönnberg, 1940) (Cebidae, Callitrichinae)

Abstract

The emperor tamarin, Tamarinus imperator, is composed of two subspecies, the nominal type, T. i. imperator, distributed between the Acre and Purus Rivers, whose range is limited between the Brazilian state of Acre and Peru are unbounded, and T. i. subgrisescens, occurring in Peru, Bolivia, and Brazil, in the Brazilian states of Acre and Amazonas. Morphologically, both taxa are easily identifiable by the pelage pattern (chromogenetic fields), and even being easily distinguishable, both lineages are considered subspecies according to the criterion based on the Biological Concept of Species from the 1970s, even without presenting some necessary criteria, such as the intergradation zone. Here we analyzed pelage traits, cranial morphometry, Cytochrome-b divergence, and distributional pattern data applying the premises of integrative taxonomy to elucidate the taxonomic status of both lineages. We hypothesize that both lineages are considered full species through a series of criteria for species recognition, such as distinguishability, level of phenotypical divergences of several morphological complexes with congruence among them, and some genetic divergence. The hybridization is unknown and the low or the lack of sampling in target areas does not allow us to determine whether a hybridization or even contact zone between the two lineages exists indeed. All character sets analyzed were congruent with each other and reinforced the high level of divergences between the two subspecies including several pelage differences, morphometry (descriptive statistics, PCA, and MANOVA), and mitochondrial DNA Cytochrome-b divergence. Most of the distribution in both lineages are allopatric, and the levels of intra-lineage phenotypical variation are much lower than between the lineages.

Molecular systematics of tamarins with emphasis on genusTamarinus(Primates, Callitrichidae)

“…Our analyses confirm the existence of two species of Tamarinus previously subsumed under the specific epithet of Tamarinus imperator , as did Gregorin et al (2023). Not only is there decisive support for the two species T .…”

“…Bayes Factors >10 are considered decisive (Kass & Raftery, 1995), and therefore there is decisive support for the existence of two species: Tamarinus imperator and Tamarinus subgrisescens . This inference is supported by diagnostic phenotypic differences between the two species (Gregorin et al, 2023; Figures S1 and S2) and disjunct distribution (Figure 2). Synonyms, diagnostic characters, type locality, and geographic distribution for two species are in Appendix S1.…”

“…This supports the taxonomy of Hershkovitz (1977) who recognized only Tamarinus labiatus albeit showing clinal phenotypic variation across a north-south gradient, while Groves (2001) revalidated the subspecies T. labiatus rufiventer (Gray, 1843) for individuals in the northern portion of the distribution of Tamarinus labiatus. Recently, the taxonomic status of Tamarinus imperator (Goeldi, 1907) was evaluated (Gregorin et al, 2023). This species has two subspecies, Tamarinus imperator imperator (Goeldi, 1907), and Tamarinus imperator subgrisescens (Lönnberg, 1940).…”

“…labiatus rufiventer (Gray, 1843) for individuals in the northern portion of the distribution of Tamarinus labiatus . Recently, the taxonomic status of Tamarinus imperator (Goeldi, 1907) was evaluated (Gregorin et al, 2023). This species has two subspecies, Tamarinus imperator imperator (Goeldi, 1907), and Tamarinus imperator subgrisescens (Lönnberg, 1940).…”

Taxonomy and systematics of the Neotropical primates: a review and update

“…Hershkovitz (1979) reviewed the taxonomy and distribution of Saguinus imperator and resurrected Saguinus imperator subgrisescens Lönnberg, 1940. Gregorin et al (2023) determined that it is a species, not a subspecies, on the basis of a study of the pelage, cranial morphometry, and cytochrome−b divergence. Hybridization is unknown but sampling in target areas is insufficient to determine a contact zone between the two lineages (Gregorin et al, 2023).…”