Importance of Dominican Republic amber for determining taxonomic bias of fossil resin preservation-A case study of spiders

This is the first time that taxonomic richness estimates have been made and compared quantitatively between extant and fossil amber faunas. Extant and extinct (Dominican Republic amber) Hispaniolan spiders are compared at family level. Overall, the two faunas are similar but some distinct differences are apparent. Hispaniolan representatives of the families Cyrtaucheniidae, Microstigmatidae, Ochyroceratidae, Palpimanidae, Tetrablemmidae, Agelenidae, Anapidae and Mysmenidae are known only from amber, whereas Drymusidae, Deinopidae, Desidae, Amaurobiidae, Prodidomidae and Zoridae are known only from the extant fauna. Many families have similar fossil and extant species diversities. Oonopidae and Dictynidae are significantly more diverse in amber. Many families currently known only from Dominican amber probably have undiscovered extant species on Hispaniola. Family species richness estimates were calculated for both fossil and extant spider faunas, but only those for the extant fauna provide results consistent with a neotropical spider assemblage. Fossil richness estimates were excessively high as a result of the large number of singletons. Nevertheless, the Dominican Republic is the only place on Earth where fossils in amber occur in sufficient numbers and that are closely related to the extant fauna, such that direct diversity/ecological comparisons can be made. Given future research directed at identifying spiders and other inclusions in the large amber collections amassed in Museums around the world, detailed comparisons of these faunas will allow us to better determine taxonomic biases associated with amber preservation.