Michael M. Webber

Wernerius inyoensis, an elusive new scorpion from the Inyo Mountains of California (Scorpiones, Vaejovidae)

Abstract A new scorpion species is described from the Inyo Mountains of California (USA). The presence of a strong subaculear spine, along with other characters, places the new species within Wernerius, an incredibly rare genus that until now consisted of only two species. Wernerius inyoensis sp. n. can be most easily distinguished from the other members of the genus by smaller adult size, femur and pedipalp dimensions, and differences in hemispermatophore morphology. Previous studies have suggested that the elusive nature of this genus may be attributed to low densities and sporadic surface activity. Herein, we provide another hypothesis, that Wernerius are primarily subterranean. Mitochondrial sequence data are provided for the holotype.

Do Sidewinder Rattlesnakes (Crotalus cerastes, Viperidae) Cease Feeding During the Breeding Season?

Seasonal aphagia (a lack of feeding) can occur if foraging and reproduction occasionally result in conflicting demands on an individual, such that one activity takes precedence over the other. We tested the hypothesis that female and male Crotalus cerastes (Sidewinders) exhibit seasonal aphagia during the reproductive season. We examined the stomach contents of preserved specimens to assess variation in the feeding rates of C. cerastes. Non-reproductive females fed during the early and late stages of the active season, but reproductive females only ate during the first half of the active season. Female Sidewinders fed throughout the early vitellogenic phases of the reproductive cycle, but exhibited a tendency to reduce or cease feeding during the later stages of the cycle (gestation). Prey consumption during early reproductive stages can provide valuable energetic resources for sustaining a females subsequent breeding activities. However, the physical burden of offspring mass and the concomitant decrease in locomotor efficiency can reduce a females foraging efficiency in the later phases of the reproductive cycle. Male C. cerastes displayed a trend to feed more frequently during the reproductive season, perhaps because enhancing their energy reserves allows males to travel longer distances and maximize encounter rates with females. The discovery of this intersexual variation in feeding patterns of C. cerastes underscores the importance of descriptive ecological studies to elucidate distinct patterns of life history evolution.

Feeding Ecology of Sidewinder Rattlesnakes, Crotalus cerastes (Viperidae)

Abstract: Dietary studies are important for understanding predator–prey relationships and species interactions because they provide information on the trophic resources available to predators and their potential impact on prey populations. We relied on stomach contents of museum specimens and literature records to examine ontogenetic (size-related), sexual, seasonal, and geographic variation in the feeding habits of Sidewinders, Crotalus cerastes. Sidewinders fed primarily on lizards and slightly less frequently on mammals; birds and snakes were rarely consumed. The vast majority of C. cerastes consumed single prey items ingested head-first. Juvenile and adult female Sidewinders consumed lizards and mammals with similar frequency. We observed an ontogenetic shift in feeding patterns of adult male C. cerastes because they included more mammals in their diets, compared with juvenile males. Sidewinders are classic ambush (sit-and-wait) predators and, as predicted by theory, actively foraging lizards and mammals comprise a considerable fraction of their prey. We documented seasonal shifts in the feeding patterns of Sidewinders, with snakes consuming a greater proportion of lizards during early spring and autumn, and a greater percentage of mammals during late spring and summer. This dietary shift likely results from seasonal changes in the activity patterns of C. cerastes, because individuals can be diurnally active during early spring and autumn but are predominantly nocturnal during late spring and summer. Adult male and female Sidewinders from the Mojave and the Sonoran deserts consumed similar proportions of lizards and mammals. Our findings regarding the trophic habits of C. cerastes contribute to our understanding of the ecology of terrestrial, venomous predators.

Two new species of Euscorpius (Scorpiones: Euscorpiidae) from Bulgaria, Serbia, and Greece

Two new species of Euscorpius Thorell, 1876 (subgenus Euscorpius s.str.) (Scorpiones: Euscorpiidae) are described based on morphology and the COI DNA barcoding marker: E. deltshevi sp. n. from northern Bulgaria and neighbouring Serbia (formerly reported as E. carpathicus) and E. solegladi sp. n. from southwestern Bulgaria and neighbouring Greece (formerly reported as E. hadzii).

A new Vaejovis C.L. Koch, 1836, the second known vorhiesi group species from the Santa Catalina Mountains of Arizona (Scorpiones, Vaejovidae)

Abstract A new species of the vorhiesi group of Vaejovis C.L. Koch, 1836, Vaejovis brysoni sp. n., is described from the Santa Catalina Mountains in southern Arizona. Vaejovis deboerae Ayrey also inhabits this mountain range, making this the first documented case of two vorhiesi group species distributed on the same mountain. When compared to all other vorhiesi group species, Vaejovis brysoni sp. n. is distinct based on several combinations of morphological characters and morphometric ratios.

An Arizona bark scorpion ( Centruroides sculpturatus ) found consuming a venomous prey item nearly twice its length

Abstract. Arizona bark scorpions (Centruroides sculpturatus Ewing) are commonly found throughout the Sonoran Desert in southwestern North America, and they are well known for being the most venomous scorpion in the United States. Despite their medical significance, C. sculpturatus remains ecologically understudied, and little is known regarding its natural foraging and feeding behaviors. Here, we present the first documented case of C. sculpturatus feeding on the Sonoran Desert centipede (Scolopendra polymorpha Wood) in the wild.