Is Callimico monotypic? A reassessment in the light of new data

Goeidi's monkey Callimico goeldii is generally regarded as the only species within its genus, despite anecdotal observations of variation in pelage co loration and an earlier report of weak outbreeding depression detected in a studbook analysis. In a recent study using seven microsatellite Loci, the genetic structure of the wild-caught founder stock for the captive populati on was characterised and associations with reproductive fitness were assess ed. A strong increase in infant mortality was found for matings between the most genetically distinct founders. To a lesser extent, matings among the most genetically similar founders also led to increased infant mortality in the offspring. Founders of an intermediate level of genetic similarity had the highest breeding success. These inbreeding and outbreeding effects wer e confirmed in a studbook analysis of first and second generation offspring . The results of that study point to a complex genetic structure within the founder stock. Some founders may originate from genetically isolated popul ations, while others may be closely related. The outbreeding effect implies that within the genus Callimico there may be more than a single species or subspecies, In the present study anecdotal reports of morphological variat ion are reviewed to evaluate this proposal, although no firm conclusions ca n be drawn. Further studies are needed to clarify the taxonomy and to provi de proposals for possible adjustments to the present breeding strategy.