Emeritus Professor of Biology
Office 1111 Biological Sciences Building
Phone (951) 827-4682
E-mail: roger.farley@ucr.edu
Degree:
Ph.D., University of California, Santa Barbara, 1966
Research in this lab has included several aspects of scorpion biology (ecology, population dynamics, behavior, physiology) summarized in the reviews cited below. Any of this work can be extended, depending upon student interest, but present emphasis is on development, comparing organogenesis and viviparity among diverse species. The intent is to relate scorpion ontogeny to their biogeography and fossil record and thereby gain a better understanding of the evolution of these survivors of the Paleozoic era.
Scorpions have an unusual integumentary layer (hyaline exocuticle) with a protein which fluoresces in ultraviolet light. This makes these animals unusually accessible for study in the field as well as laboratory. The hyaline layer in scorpions has also resulted in a preservational bias among other arthropods. We thus have some fossils, the earliest from the Silurian period about 430 million years ago. Those ancient scorpions (aquatic, more than 50 families) reached nearly a meter in length. All disappeared (Devonian/Carboniferous), possibly from vulnerability during molt and from piscine or other predation on eggs, juveniles and/or adults. The scorpion survivors are small, cryptic, terrestrial forms (9-15 families) with booklungs and viviparity. Some indications of the water-to-land transition and other aspects of scorpion evolution are evident in fossils and the ontogeny of extant species.
Scorpions were present during Pangaea, apparently dispersed with the continents and are now widely distributed. Extant species show conservative evolution except for differences in venom toxicity and maternal mechanisms and structures for embryo nourishment in utero. These structures are mainly non-placental, without specialized vascularization, in contrast to viviparous fish (more than 40 families). The complexities of the latter are well studied, and scorpion viviparity provides an invertebrate comparison with the evolution of viviparity in higher forms.