Comparing amber fossil assemblages across the Cenozoic.

Area of Science:

• Paleontology
• Paleoecology
• Arthropod Biology

Background:

• Faunistic comparisons of fossilized organisms in amber are crucial for understanding past ecosystems.
• However, differences in amber's botanical, geographical, and age characteristics necessitate uniform resin sampling.
• Previous studies lacked robust evidence for uniform trapping across diverse amber types.

Purpose of the Study:

• To determine if fossil-trapping resins sampled organisms uniformly across different amber types.
• To validate the use of amber for comparative paleoecological studies across geological time.
• To investigate the influence of amber-producing tree structure on trapped faunal communities.

Main Methods:

• Analysis of size distributions of 671 fossilized spider species from Baltic and Dominican ambers.
• Comparison of spider size data across different behavioral guilds (web-spinners vs. active hunters).
• Evaluation of evidence for uniform resin trapping and ecological information retention.

Main Results:

• Ecological information regarding ancient spider communities is retained in both Baltic and Dominican ambers.
• Greater structural complexity in Baltic amber trees correlates with larger web-spinning spiders compared to Dominican amber.
• No significant size differences were observed in active hunting spider guilds between the two ambers.

Conclusions:

• The study provides the first evidence that resins trapped organisms uniformly, irrespective of amber type or age.
• Comparative analyses of amber paleoecosystem structures across deep time are scientifically valid.
• Amber's utility as a tool for reconstructing past biodiversity and ecological dynamics is confirmed.