Tag Archives: evolution

New paper published in Subterranean Biology on coprophagy in the Grotto Salamander

A new paper was just published on coprophagy in a cave salamander involving collaborators from the New Jersey Institute of Technology, The Nature Conservancy, San Antonio Zoo, and U.S. Fish & Wildlife Service.

Soares D, Adams R, Hammond S, Slay ME, Fenolio DB, Niemiller ML. 2017. Evolution of coprophagy and nutrient absorption in a cave salamander. Subterranean Biology 24: 1–9.

The transition from carnivory to omnivory is poorly understood. The ability to feed at more than one trophic level theoretically increases an animal’s fitness in a novel environment. Because of the absence of light and photosynthesis, most subterranean ecosystems are characterized by very few trophic levels, such that food scarcity is a challenge in many subterranean habitats. One strategy against starvation is to expand diet breadth. Grotto Salamanders (Eurycea spelaea (Stejneger, 1892)) are known to ingest bat guano deliberately, challenging the general understanding that salamanders are strictly carnivorous. Here we tested the hypothesis that grotto salamanders have broadened their diet related to cave adaptation and found that, although coprophagous behavior is present, salamanders are unable to acquire sufficient nutrition from bat guano alone. Our results suggest that the coprophagic behavior has emerged prior to physiological or gut biome adaptations.

New paper published in Copeia on morphological evolution in amblyopsid cavefishes

A paper on the morphological evolution of amblyopsid cavefishes was recently published in the journal Copeia. The full citation and abstract are below.

Armbruster JW, Niemiller ML, & Hart PB. 2016. Morphological evolution of the cave-, spring- and swampfishes of the family Amblyopsidae (Percopsiformes). Copeia 104: 763–777.

The Amblyopsidae is a small family of fishes from North America in which most of the species occur in caves. Despite considerable interest and study by biologists, a comprehensive morphological phylogenetic analysis of the family has not been conducted to date. We examined the skeletal morphology of all six genera and recognized species, which included 66 characters. The resulting phylogeny was compared to morphological- and molecular-based phylogenies of previous studies. Results showed a progression of cave adaptation that was significantly different from previous phylogenetic studies. Amblyopsidae was supported by 34 synapomorphies of the skeleton, but relationships within the Amblyopsidae were comparatively weak. The relationships of amblyopsids are likely influenced by morphological convergence as well as changes in the timing of development of some characters. Heterochrony is most visible in the unfused bones of the dorsal portion of the skull. The sister group to Amblyopsidae is Aphredoderidae (pirate perches), and the main character that supports this relationship is the presence of a unique set of upper jaw bones termed here lateromaxillae. This relationship is also supported by an anterior position of the vent, which is used for expelling gametes in Aphredoderus and for moving eggs to the gill chamber in Amblyopsis. It is more likely that Amblyopsis is the only branchial brooding amblyopsid and all other species likely exhibit transbranchioral spawning.