Presentation Title

The evolution of placentotrophy in the Southern Africa Clade of the Skink Genus Trachylepis.

Faculty Mentor

Marcelo N. Pires

Start Date

17-11-2018 8:30 AM

End Date

17-11-2018 10:30 AM

Location

CREVELING 58

Session

POSTER 1

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

The evolution of placentotrophy in the Southern Africa Clade of the Skink Genus Trachylepis.

Authors: Brett Schiller, Noah Husband, Sydney Davis, Anna Groehnert, Israel Ocampo.

Mentor: Marcelo N. Pires. (Department of Biological Sciences, Saddleback College, 28000 Marguerite Pkwy. Mission Viejo, CA 92692; mpires@saddleback.edu)

Multiple, independent evolutionary origins of biological traits are often associated with a putative adaptive value. The convergent evolution of mimicry, for example, is a well-known case of the power of natural selection. Therefore, the observation of a complex trait that has evolved independently in multiple lineages but shows no clear adaptive value is intriguing. Such is the case of the evolution of extensive placentotrophy (resource transfer from mother to embryos via placental membranes), an evolutionary event that has occurred in many animal species, but for which no clear or comprehensive adaptive explanation is available. The study of the ecological and evolutionary forces that have favored the origin of placentotrophy requires a group of closely related species that vary in their degree of placentotrophy and exhibit convergent evolution of extensive placentotrophy. We hypothesize that the southern Africa clade of the skink genus Trachylepis may serve as a useful model system for such studies. Here, we report the finding that the closely related species T. spilogaster, T. striata, T. sulcata, and T. variegata express at least intermediate degrees of placentotrophy. The sister species T. occidentalis, on the other hand, is known to be oviparous in some populations and possibly express incipient placentotrophy in other populations. These observations infer that this skink clade includes a previously undocumented evolutionary origin of intermediate to extensive placentotrophy in vertebrates.

Summary of research results to be presented

Research is ongoing, measurements of sexual morphology are still being taken into account. At the current rate, most of the results still need greater analysis to come to a conclusion. The current thought is that this skink clade includes a previously undocumented evolutionary origin of intermediate to extensive placentotrophy in vertebrates. The advancement of this information could perhaps aid in the phylogenetic analysis of embryonic development.

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Nov 17th, 8:30 AM Nov 17th, 10:30 AM

The evolution of placentotrophy in the Southern Africa Clade of the Skink Genus Trachylepis.

CREVELING 58

The evolution of placentotrophy in the Southern Africa Clade of the Skink Genus Trachylepis.

Authors: Brett Schiller, Noah Husband, Sydney Davis, Anna Groehnert, Israel Ocampo.

Mentor: Marcelo N. Pires. (Department of Biological Sciences, Saddleback College, 28000 Marguerite Pkwy. Mission Viejo, CA 92692; mpires@saddleback.edu)

Multiple, independent evolutionary origins of biological traits are often associated with a putative adaptive value. The convergent evolution of mimicry, for example, is a well-known case of the power of natural selection. Therefore, the observation of a complex trait that has evolved independently in multiple lineages but shows no clear adaptive value is intriguing. Such is the case of the evolution of extensive placentotrophy (resource transfer from mother to embryos via placental membranes), an evolutionary event that has occurred in many animal species, but for which no clear or comprehensive adaptive explanation is available. The study of the ecological and evolutionary forces that have favored the origin of placentotrophy requires a group of closely related species that vary in their degree of placentotrophy and exhibit convergent evolution of extensive placentotrophy. We hypothesize that the southern Africa clade of the skink genus Trachylepis may serve as a useful model system for such studies. Here, we report the finding that the closely related species T. spilogaster, T. striata, T. sulcata, and T. variegata express at least intermediate degrees of placentotrophy. The sister species T. occidentalis, on the other hand, is known to be oviparous in some populations and possibly express incipient placentotrophy in other populations. These observations infer that this skink clade includes a previously undocumented evolutionary origin of intermediate to extensive placentotrophy in vertebrates.