Gustavo Hormiga

Ruth Weintraub Professor
Lisner Hall 421
Phone: 202-994-1095


Lab office: Bell Hall 405

Areas of Expertise

Systematics of spiders; evolutionary biology of spiders, especially orb weavers and their relatives.

Current Research

The research in my laboratory focuses on the systematics and evolutionary biology of spiders, with emphasis on orbweavers and their close relatives (Orbiculariae). Most of the species-level systematic work in my lab addresses three spider lineages: the sheet weaving family Linyphiidae and Pimoidae, and the orb weaving families Tetragnathidae and Mysmenidae. We use morphological, molecular and behavioral characters to reconstruct the phylogenetic relationships of our study organisms, to tackle questions that span from species level problems to interrelationships of families. I am also interested in applying phylogenetic results to more general questions in evolutionary biology such as the evolution of sexual size dimorphism in orbweaving spiders (Hormiga et al., 2000) Tetragnathidae or the patterns of insular diversification and colonization in the Hawaiian archipelago (Hormiga et al., 2003). This work highlights the importance of reconstructing the history of evolutionary changes for addressing comparative questions. For example, the results of our research show that the extensively studied "male dwarfism" of nephiline spiders (Tetragnathidae), when placed in a phylogenetic context , is in fact a case of female gigantism.

Check out the following links to read more about some of our current projects:

Assembling the Tree of Life: Phylogeny of Spiders
PEET: Systematics and Monography of Araneoid Spiders
PBI: Goblin Spider Project
PANCODING: Panamanian Arthropods barcoding Initiative


B.Sc., Universidad de Barcelona, 1985
M.S., Ph.D., University of Maryland at College Park, 1992, 1995


Full text publicationsFor reprint requests, please send an email to

Dimitrov D., Álvarez-Padilla F., Hormiga, G. In press. The female genitalic morphology of the orb weaving spider genus Agriognatha (Araneae, Tetraganthidae). Journal of Morphology.

Hormiga, G., F. Álvarez-Padilla and S.P. Benjamin. In press. First records of extant Hispaniolan spiders of the families Mysmenidae, Symphytognathidae and Ochyroceratidae (Araneae), including a new species of Ochyrocera. American Museum Novitates.

Lopardo, L. and G. Hormiga. In press. On the spider genus Cepheia Simon 1894 (Araneae, Synaphridae). American Museum Novitates.

Ramírez, M.J., J.A. Coddington, W.P. Maddison, P.E. Midford, L. Prendini, J. Miller, C.E. Griswold, G. Hormiga, P. Sierwald, N. Scharff, S.P. Benjamin, and W.C. Wheeler. 2007. Linking of Digital Images to Phylogenetic Data Matrices Using a Morphological Ontology. Systematic Biology, 56 (2): 283-294.

Lopardo, L., G. Hormiga and A. Melic. 2007. Spinneret spigot morphology in synaphrid spiders (Araneae, Synaphridae), with comments on the systematics of the family and description of a new species of Synaphris Simon 1894 from Spain. American Museum Novitates, 3556: 1-26.

Hormiga, G. and S. Lew. 2005. Chapter 48: Pimoidae. In: Darrell Ubick, Pierre Paquin, Paula E. Cushing, & Vince Roth (eds.) Spiders of North America: an identification manual (pp. 197-198).

Hormiga, G., D.J. Buckle and N. Scharff. 2005. Nanoa, an enigmatic new genus of pimoid spiders from western North America (Pimoidae, Araneae). Zoological Journal of the Linnean Society 145: 249-262.

Hormiga, G. and N. Scharff. 2005. Monophyly and phylogenetic placement of the spider genus Labulla Simon, 1884 (Araneae, Linyphiidae) and description of the new genus Pecado. Zoological Journal of the Linnean Society 143: 359-404.

Miller, J.A. and G. Hormiga. 2004. Clade Stability and the Addition of Data - A Case Study from Erigonine Spiders (Araneae: Linyphiidae, Erigoninae). Cladistics 20: 385-442. (cover article)

Hormiga, G. 2003. Weintrauboa, a new genus of pimoid spiders from Japan and adjacent islands, with comments on the monophyly and diagnosis of the family Pimoidae and the genus Pimoa (Araneoidea, Araneae). Zoological Journal of the Linnean Society, 139: 261-281.

Hormiga, G., Arnedo, M. Gillespie, R. G. 2003. Speciation on a Conveyor Belt: Sequen-tial Colonization of the Hawaiian Islands by Orsonwelles Spiders (Araneae, Linyphiidae). Systematic Biology 52 (1): 70-88 (cover article).

Hormiga, G. 2002. Orsonwelles, a new genus of giant linyphiid spiders (Araneae) from the Hawaiian Islands. Invertebrate Systematics 16: 369-448 (cover article).

Hormiga, G., N. Scharff, and J. Coddington. 2000. The Phylogenetic Basis of Sexual Size Dimorphism in Orb-Weaving Spiders (Araneae, Orbiculariae). Systematic Biology 49(3): 435-462.

Hormiga, G. 2000a. Higher level phylogenetics of erigonine spiders (Araneae, Linyphiidae, Erigoninae). Smithsonian Contributions to Zoology, 609: 1-160.

Griswold, C., J. Coddington, G. Hormiga, and N. Scharff. 1998. Phylogeny of the orb web building spiders (Araneomorphae, Orbiculariae). Zoological Journal of the Linnean Society, 123: 1-99.

Coddington, J.A., G. Hormiga, and N. Scharff. 1997. Giant Female or Dwarf Male Spiders? Nature, 385: 687-688.

Hormiga, G., W.G. Eberhard, and J.A. Coddington. 1995. Web construction behavior in Australian Phonognatha and the phylogeny of nephiline and tetragnathid spiders (Araneae, Tetragnathidae). Australian Journal of Zoology, 43: 313-364.

Hormiga, G. 1994a. A revision and cladistic analysis of the spider family Pimoidae (Araneae: Araneoidea). Smithsonian Contributions to Zoology, 549: 1-105.

Hormiga, G. 1994b. Cladistics and the comparative morphology of linyphiid spiders and their relatives (Araneae, Araneoidea, Linyphiidae). Zoological Journal of the Linnean Society, 111: 1-71. 

Hormiga, G. 1993a. Implications of the phylogeny of Pimoidae for the systematics of linyphiid spiders (Araneae, Araneoidea, Linyphiidae). Memoirs of the Queensland Museum, 33(2): 533-542.

Classes Taught

BISC 6210 - Phylogenetic Systematics
BISC 6213 - Principles of Taxonomy: Documenting Diversity
BISC 6214 - The Phylogenetic Basis of Comparative Biology
BISC 6207 - Current Topics in Systematic Biology
Courses in Systematics and Evolution at GW