Pikes Peak Pebble Pups

Pikes Peak Pebble Pups

Monday, December 17, 2012

A Florissant Fossil Beds Spider Discovery: Family Lycosidae

By Zachary J. Sepulveda and Steven Wade Veatch

The Florissant Fossil Beds National Monument is known worldwide for its late Eocene (34 mya) fossil plants and insects. Recently, a fossil spider was discovered at the commercial quarry that is near the fossil beds (Figure 1). Due to the condition of this fossil, it can be assigned only to the family Lycosidae (Table 1) (Rasnitsyn, 2012). This classification would make it a wolf spider.

This fossil wolf spider lived 34 mya under Florissant rocks, within the forest litter, or on short herbaceous plants (Meyer, 2003). Based on its modern relatives, this spider would have had colors that helped to camouflage it, allowing it to hide from its prey (Meyer, 2003). According to the Florissant Fossil Beds National Monument fossil database, only one other member of the family Lycosidae (from the Greek word for wolf) has been discovered there. Petrunkevitch (1922) described this fossil and assigned it to the species Lycosa florissanti, from a well-preserved fossil specimen.

Spiders belong to the class Arachnida. Unlike insects, arachnids have eight legs instead of six, have two body sections instead of three, and do not have antennae or wings.

Figure 1. Image of fossil spider (family Lycosidae) split along the bedding plane of the ancient Lake Florissant shales shows the two halves. Found at the commercial fossil quarry near the Florissant Fossil Beds National Monument. Scale bar in centimeters. Photo © S. W. Veatch.

Table 1. Taxonomy of Wolf Spider from the Florissant Fossil Quarry

Kingdom: Animalia

Phylum: Arthropoda

Subphylum: Chelicerata

Class: Arachnida

Order: Araneae

Suborder: Labidognathidae

Family: Lycosidae

These spiders are incredibly successful—with a lineage stretching back millions of years. With over 100 genera and 2,300 species, they are capable predators spread throughout the entire globe and can inhabit almost every type of environment. From shrub lands to coastal forests, from gardens to alpine meadows, most of these spiders are wanderers and vagrants with no set home or residence but can live just about anywhere (Wolf Spiders in Nebraska).

Wolf spiders hunt in many different ways, depending on the species, size, prey types, and habitats. These spiders are known to ambush and even chase down insect prey. Some species jump from hiding to pounce on prey. These organisms are important controllers of harmful insects, and even though they can be dangerous to people, their presence is generally considered favorable. Most of the few species that stay in one place throughout their lives live in small burrows lined with webs. They simply sit inside and wait for prey to come close, and then they spring from their burrows and attack. Some of these desert dwelling burrowing spiders will even plug their burrows with leaves and pebbles to avoid flooding (Wolf Spiders).

Wolf spiders range in body size from 10.2 mm (0.4 inches) to 30.5 mm (1.2 inches) long, and can be even larger in diameter with their legs outstretched. In some species, the venom is mild, but in others it is potent and is known to cause necrotic wounds, which create an area of dead flesh (Isbister and Framenau, 2004). Most of the species that have necrotic bites are native to South America and Australia (Ribeiro et al., 1990).

The identification of fossil spiders at Florissant remains difficult because they tend to be poorly preserved, owing to their soft bodies as compared to the harder bodies of insects. This wolf spider, found on a sunny summer day in 2012, is no different than the other fossil spiders that leave unclear impressions in the shale, making identification to the species level all but impossible.

References Cited:

Isbister, G. K., and Framenau, V. W. (2004). Australian wolf spider bites (lycosidae): Clinical effects and influence of species on bite circumstances. Clinical Toxicology, 42 (2), 153-161.

Meyer, H. (2003). The Fossils of Florissant. Washington: Smithsonian Books.

Petrunkevitch, A. (1922). Tertiary spiders and opilionids of North America. Transactions of the Connecticut Academy of Arts and Sciences, 25, 211-279

Rasnitsyn, A. (2012, June 1). Entomologist, Russian Academy of Sciences, Moscow. [Personal Communication].

Ribeiro, L. A., Jorge, M. T., Piesco, R. V., and  Nishioka, S. A. (1990). Wolf spider bites in São Paulo, Brazil: A clinical and epidemiological study of 515 cases. Toxicon, 28 (6), 715-717.

Wolf spiders in Nebraska. (n.d.). Retrieved from http://lancaster.unl.edu/pest/resources/wolfspider.shtml

Wolf spiders. (n.d.) Australasian Arachnology Society, Retrieved from http://www.australasian-arachnology.org/arachnology/araneae/lycosidae

About the authors:

Zachary Sepulveda recently moved to the Pikes Peak region from San Diego, CA. He became interested in paleontology by visiting the La Brea Tar Pits in Los Angeles as often as he could. He is a junior member of the Colorado Springs Mineralogical Society and is part of the Pikes Peak Pebble Pups and Earth Science Scholars Program. Zach is 15 years old and is in 10th grade at Palmer Ridge High School in Monument, Colorado.

Steven Veatch lives in the Pikes Peak region. His has been a member of the Colorado Springs Mineralogical Society since 5th grade and is a member of the Western Interior Paleontological Society. Veatch is the leader of the Pikes Peak Pebble Pups and Earth Science Scholars Program. Veatch is an adjunct professor at Emporia State University. Veatch lives next to the Florissant fossil beds and continues research in the region.

Welcome! This is the gateway to adventure and discovery

Through this blog pebble pups and junior members of the Colorado Springs Mineralogical Society can access their lessons, work on assignments and projects, and receive details about field trips in the Pikes Peak Region. This Internet program is also suitable for young people who are interested in Earth science but do not live near a rock club or gem and mineral society or for young people anywhere who want a deeper dive into these topics. The only requirement is that all participants must be members of the Colorado Springs Mineralogical Society and must fill out the CSMS membership form (under important websites) and send their registration and membership fee in. Steven Veatch is the senior instructor and will need an email from you with your name, address, phone number, and permission from your parents to participate in this program.