SYSTEMATIC IMPLICATIONS OF CRANIOMETRIC VARIATION IN PROECHIMYS-IHERINGI THOMAS (RODENTIA, ECHIMYIDAE)

Abstract

Proechimys iheringi is an echimyid rodent that ranges in distribution from the state of Bahia to the state of Sao Paulo in southeastern Brazil. The current taxonomic treatment of P. iheringi stems from MOOJEN (1948), and includes a formal subspecific structure and an alternative hypothesis which postulates various levels of differentiation and isolation between geographic populations of R iheringi. According to the formal structure six subspecies are recognized primarily on the basis of increasing number of cheekteeth counterfolds from northern to southern localities, whereas under the alternative hypothesis two forms, P. i. iheringi and P. i. paratus, arc regarded as specifically isolated. We examined variation in cranial morphometric traits in all subspecies recognized by MOOJEN (1948), in addition to P. i. eliasi, a new form recently described from the state of Rio de Janeiro (PESSOA and REIS 1993). Cranial variation as revealed by multivariate analysis is not congruent with the formal subspecific structure but rather supports MOOJEN'S (1948) conjecture that P. i. paratus and P. i. iheringi may be specifically differentiated. The remaining forms currently recognized as P. i. denigratus, P. i. gratiosus, P. i. panema, P. i. bonafidei, and P. i. eliasi may be part of another taxon specifically distinct from P. i. paratus and P. i. iheringi.2324179518120