International Tarantula Occurrence Database (ITOD): Research-Grade Dataset Curation and Growth Assessment
International Tarantula Occurrence Database (ITOD): Research-Grade Dataset Curation and Growth Assessment
June 5, 2026
The International Tarantula Occurrence Database (ITOD) continues to develop as a curated repository of research-grade tarantula observations derived from iNaturalist. Rather than generating new occurrence records, the project systematically organizes and refines existing iNaturalist observations into a focused dataset intended to facilitate biodiversity research, ecological analysis, and long-term monitoring of theraphosid spiders.
Purpose of the ITOD Project
All observations included within ITOD originate from the broader iNaturalist platform. The primary goal of the project is not to create an independent occurrence database, but rather to identify, organize, and curate observations that meet research-quality standards while maintaining a consistent focus on members of the family Theraphosidae.
By consolidating these observations into a dedicated project, ITOD provides researchers, naturalists, and enthusiasts with a readily accessible dataset that emphasizes confirmed species occurrences and high-quality geographic records.
Dataset Overview
A recent query of the ITOD project returned:
32,116 observations
32,116 research-grade observations (100%)
108 species represented
51 genera represented
56 countries and territories represented
Observation dates spanning 2008–2026
Because ITOD applies project-specific curation criteria, the resulting dataset represents a highly refined subset of the broader iNaturalist tarantula dataset. Every observation included in the project has achieved research-grade status through community identification and quality-control processes established by iNaturalist.
Comparison with a Broader iNaturalist Query
To better understand the scope of the project, the ITOD dataset was compared against a separate export of research-grade Theraphosidae observations from iNaturalist.
The broader export contained:
29,952 research-grade observations
97 species
52 countries
The ITOD project returned:
32,116 research-grade observations
108 species
56 countries and territories
These differences primarily reflect variations in query structure, project curation, taxonomic coverage, and the inclusion of records that may not be captured through a single taxon-based export. Importantly, both datasets originate from iNaturalist observations and should be viewed as complementary representations of the same underlying community science resource.
Observation Growth Through Time
The ITOD dataset also illustrates the remarkable growth of tarantula observations being contributed to iNaturalist.
| Year | Observations |
|---|---|
| 2017 | 1,102 |
| 2018 | 1,618 |
| 2019 | 2,405 |
| 2020 | 2,131 |
| 2021 | 2,836 |
| 2022 | 3,227 |
| 2023 | 3,662 |
| 2024 | 4,999 |
| 2025 | 5,511 |
| 2026* | 1,846 |
*2026 represents a partial year.
The steady increase in observations demonstrates continued growth in public participation, geographic coverage, and taxonomic documentation on iNaturalist. ITOD serves as a mechanism for organizing these contributions into a coherent dataset suitable for research and analysis.
Geographic Representation
Observations within the curated dataset currently span 56 countries and territories. The countries contributing the largest numbers of records include:
| Country | Observations |
|---|---|
| United States | 18,474 |
| Mexico | 4,217 |
| French Guiana | 1,799 |
| Costa Rica | 1,474 |
| Trinidad and Tobago | 805 |
| Puerto Rico | 722 |
| Brazil | 712 |
| Chile | 710 |
| Colombia | 320 |
| Belize | 308 |
These records collectively provide one of the most geographically extensive research-grade collections of tarantula observations currently available through community science platforms.
Most Frequently Observed Species
The most commonly documented species within the curated ITOD dataset are:
| Species | Observations |
|---|---|
| Aphonopelma hentzi | 6,030 |
| Aphonopelma iodius | 3,896 |
| Aphonopelma chalcodes | 2,960 |
| Avicularia avicularia | 2,083 |
| Aphonopelma anax | 1,737 |
| Abdomegaphobema mesomelas | 1,476 |
| Aphonopelma eutylenum | 1,292 |
| Aphonopelma steindachneri | 1,254 |
| Tliltocatl epicureanus | 824 |
| Aphonopelma marxi | 806 |
The prominence of these species reflects both their natural abundance and the concentration of observer activity in regions where they occur.
Value of a Curated Research-Grade Dataset
Although the underlying observations remain part of iNaturalist, project-level curation provides several important advantages:
Centralized access to research-grade tarantula records
Improved taxonomic consistency
Easier dataset retrieval and analysis
Simplified geographic and ecological assessments
Enhanced utility for biodiversity research and conservation studies
Long-term monitoring of community science coverage and participation
By focusing exclusively on research-grade observations, ITOD provides a higher-confidence dataset for analyses involving species distributions, habitat associations, elevational patterns, and biogeographic investigations.
Looking Forward
As iNaturalist continues to grow, the number of verified tarantula observations available for inclusion within ITOD will also expand. The project's role is to curate, organize, and maintain a high-quality subset of these observations, ensuring that researchers and naturalists have access to a consistent and reliable resource for studying the diversity and distribution of the world's tarantulas.
The continued success of ITOD ultimately reflects the efforts of thousands of iNaturalist observers and identifiers whose contributions make large-scale biodiversity datasets possible.
International Tarantula Occurrence Database (ITOD)