20th International Congress of Arachnology

DENVER MUSEUM OF NATURE & SCIENCE

REPORTS

No. 3, July 2, 2016

International Congress of Arachnology

opportunity to identify indicators of a ‘healthy’ and sus-

tainable pasture. Spiders in pastures at Polyface Farms

(Swope, VA) under high-intensity, low-frequency rotational

grazing, and three immediately adjacent continuously

(conventionally) grazed pastures were collected in 0.25m

areas employing an intense two-stage suction-sampling

system of the vegetation and substrate. The most abundant

spider families in the pastures were Linyphiidae, Lycosidae,

Thomisidae, Araneidae, Salticidae, Clubionidae, Tetragnath-

idae, and Oxyopidae; the linyphiids were most abundant.

Although spider abundances significantly decreased after

the initial rotational grazing event, their numbers, diversity,

and evenness one day after grazing were still greater than

in conventionally grazed pastures. Araneid, salticid, and

clubionid proportions were most impacted after rotational

grazing. The overall proportional representations of major

spider taxa in rotationally grazed pastures changed after

grazing, and resembled conventionally grazed areas. While

spider abundances doubled post-grazing, spider number

decreased during this same time period in conventionally

grazed pastures. Discriminant analysis using spider genera

reveals a clear separation of the rotationally grazed pastures

(both pre- and post-grazing), from the conventionally

grazed pastures. Differences in vegetation structure and

soil compaction between pastures under rotational grazing

versus conventional grazing may explain observed differ-

ences in the spider communities. With further sampling and

analyses, pasture health may be assessed in the future by

determining spider community structure.

Keywords: spider communities, rotational grazing, com-

munity dynamics, succession, pastures

Student - poster presentation

Characterization of cryptic diversity of

Phrynidae in the Caribbean based on DNA

barcoding

*Laura Caicedo-Quiroga

, Laura May-Collado

, Giselle Veve

Greta Binford

, Jonathan Coddington

, Ingi Agnarsson

1,3

University of Vermont, Department of Biology, 109 Car-

rigan Drive, Burlington, VT 05405-0086, United States;

Lewis & Clark College, Department of Biology, Portland

Oregon. 0615 SW Palatine Hill Rd;

Department of

Entomology, National Museum of Natural History,

Smithsonian Institution, Washington, DC, USA

lra.caicedo@gmail.com

The Caribbean biogeography project (CarBio) is begin-

ning to reveal the vast biodiversity of arachnids in the

region. Whip-spiders are a good example, as shown in

the first molecular phylogeny of

Phrynus

from Puerto

Rico and Dominican Republic which discovered numer-

ous overlooked ‘cryptic’ species. Our work expands upon

this phylogeny with samples from the remaining Greater

Antilles as well as several of the Lesser Antilles, and

Caribbean coasts of the Americas. We present prelimi-

nary results based on DNA barcoding with Cytochrome C

Oxidase Subunit I for 402 specimens representing eight

species from two genera of Phrynidae:

Paraphrynus

and

Phrynus

. Among the eight named species, we identify 40

clades separated by 5% or more sequence divergence. None

of the densely sampled nominal species is monospecific,

and many are non-monophyletic.

Phrynus longipes

rather than representing a widespread species, is found

to be a paraphyletic assemblage of multiple single-island

endemics, while

Phrynus marginemaculatus

is identified

as a monophyletic complex of at least five putative species.

Short range endemism characterizes all groups both on

islands and the mainland, with genetic variation showing

strong geographic structure. In addition we see evidence

of multiple colonization events to the Caribbean islands

and subsequent radiation of multiple lineages within

islands. Clade divergences are structured by geologic

barriers within islands, notably among cave systems, in

support of the “islands within islands” hypothesis.

Keywords: Amblypygi, barcoding, Caribbean, biodiver-

sity, cryptic radiation

Student - oral presentation

Systematic revision of genus

Crassicrus

Reichling & West, 1996 (Araneae:

Theraphosidae)

*Daniela T. Candia-Ramírez

1,2

, Oscar F. Francke

Posgrado en Ciencias Biológicas, Universidad Nacio-

nal Autónoma de México, Av. Universidad 3000,

CP 04510, Coyoacán, Ciudad de México, México;