Research

Research is organized here around two rodent-centered themes: specimen-based studies of anatomical variation and broad-scale studies of desert adaptation and diversity. The sections below explain how questions are framed and tested within each theme, followed by a separate account of additional collaborations and projects. 

A short summary of the published papers can be found on Kudos and full texts in the publications page.

Rodent form and evolution from museum specimens

Natural-history collections provide specimens with documented taxonomic and locality information for studying morphological variation within particular rodent lineages. We quantify skull and other anatomical structures using conventional measurements or two- and three-dimensional geometric morphometrics, depending on the question. 

These studies examine how morphology differs among populations, species, and higher taxonomic groups, and whether those differences are associated with allometry, ecology, geography, or evolutionary relationships. Morphological variation can also provide evidence for species identification and taxonomic revision. Applying comparable specimen-based approaches across different rodent groups allows us to distinguish recurring influences on form from patterns particular to individual lineages.

Representative studies

• Cranial shape variation in kangaroo mice (Microdipodops): Taxonomic insights and ecological adaptations

• Allometry and ecology shape cranial variation in phyllotine gerbil mice (Eligmodontia)

• Interspecific cranial variation in coarse-haired pocket mice (Chaetodipus): a geometric morphometric analysis within a phylogenetic framework

Desert adaptation and rodent diversity across regions

At broader evolutionary scales, we examine how rodent traits and distributions are associated with environmental conditions across many lineages and regions. Species-level comparative analyses test whether traits such as skull and dental morphology, body size, and geographic range covary with aridity, climate, or vegetation after accounting for shared evolutionary history. These analyses help distinguish repeated environmental responses from similarities inherited through common ancestry. 

At the assemblage level, the focus shifts from individual species to the sets of species occurring together across geographic regions. We examine how environmental conditions, functional traits, geographic ranges, and evolutionary relationships shape global patterns of community structure and extinction risk. This extends the study of rodent form and evolution from individual lineages to broader patterns of biodiversity.

Representative studies

• A phylogenetic test of adaptation to deserts and aridity in skull and dental morphology across rodents

• Environmental correlates of body size influence range size and extinction risk: A global study in rodents

• Global phylogenetic and functional structure of rodent assemblages

Additional projects and collaborations

Dr. Hasan Alhaddad leads the camel genetics program through HA Genetics. Within this collaboration, our contribution centers on traditional and geometric morphometrics and statistical analysis of head and body form.

Separate, occasional projects apply comparative or quantitative methods beyond the lab's core rodent themes. They include horse facial form, mudskipper terrestriality, comparisons among species-level environmental-data sources, and undergraduate biology performance.

Representative studies

• Classifying camel breeds using geometric morphometrics: A case study in Kuwait

• Geometric morphometrics of face profile across horse breeds and within Arabian horses

• Phylogenetics and the evolution of terrestriality in mudskippers (Gobiidae: Oxudercinae)

• High correlation between species-level environmental data estimates extracted from IUCN expert range maps and from GBIF occurrence data

The Publications page provides the complete record across these projects.

Museum specimen image archive and collaboration

The lab has assembled a photographic archive from museum specimens photographed by lab members, comprising 9183 rodent vouchers representing 545 operational taxonomic units (OTUs) in 260 genera, 23 families, and 3 suborders from AMNH, FMNH, LCM, MVZ, OMNH, UF, and USNM. The searchable catalogue lists each photographed specimen by suborder, family, genus, taxon or OTU, holding collection, and complete voucher identifier. Taxonomic names have been standardized from those recorded by the museums to follow the Mammal Diversity Database (MDD), version 2.5 (28 July 2026), where applicable.

The archive can help researchers identify relevant specimens and datasets for comparative morphology, geometric morphometrics, taxonomy, and related studies. Specimen records, measurement files, landmark coordinates, and analytical workflows are organized together, while R scripts document data preparation, statistical analyses, and figure production. This organization facilitates collaboration by allowing compatible datasets to be combined across projects for larger comparative studies, while maintaining transparent and reproducible workflows.

Browse the catalogue or contact the lab with the scientific name and voucher identifier of interest to discuss possible use of collected data or collaboration. Photographs were taken by the lab and may be shared subject to applicable policies of the holding collection.