Morphological Description of Spindly Leg Syndrome in Golden Mantella (Mantella aurantiaca) at the Smithsonian National Zoological Park

Abstract

Amphibian populations are declining internationally, making captive propagation a critical part of conserving species (Stuart et al., 2008). Amphibian declines are attributed to several factors, including epidemics caused by the spread of pathogens such as Batrachochytrium dendrobatidis (Berger et al., 1998; Pessier et al., 1999; Skerratt et al., 2007). Habitat destruction and unregulated collection of aesthetically pleasing species for the pet trade also contribute to the decline of amphibian populations, such as that of the Madagascan golden mantella (Mantella aurantiaca) (Andreone et al., 2008). Although habitat preservation can be time-consuming and impeded by politics and a lack of enforcement agencies, captive breeding efforts provide an immediate option for species maintenance and survival. Captive propagation can help conservation biologists build assurance colonies in situ or ex situ, provide scientists with invaluable information to help mitigate threats to wild populations, and prevent further population declines through reducing the incentives of illegal collecting by providing animals for the pet trade. Although captive propagation efforts are valuable to conservation (Wiese and Hutchins, 1995; Stuart et al., 2008), it has proven difficult for many amphibian species due to constraints on husbandry parameters, such as water quality, lighting, diet, and genetic diversity (Brown and Zippel, 2007). The inability to provide parameters mimicking those experienced in situ, or the lack of information on in situ parameters, can lead to failed breeding attempts or onset of disease processes. Our investigation focuses on a developmental disorder known as spindly leg syndrome (SLS). Also known as skeletal and muscular underdevelopment, SLS presents as asymmetric limb deformities, poor joint development, atrophy of the muscles, absence of the bones distal to the humeri, and mal-development of the humeroulnar and carpometacarpal joints (Hakvoort et al., 1995). More simply, SLS is characterized by developmental abnormalities such as underdeveloped or malformed limbs and is ultimately fatal in most cases (Marlett et al., 1988; Wright and Whitaker, 2001). The cause of SLS is undetermined, although it is thought to be due to one or a combination of the following: nutrition, genetics, environment, and trauma I N M Y E X P E R I E N C E