Sharp-beaked Ground-finch (Geospiza difficilis) - HBW 16, p. 680

Taxonomy: Geospiza difficilis Sharpe, 1888, Pinta (formerly Abington Island), Galapagos Islands.
Recent molecular-genetic research suggests that the Galapagos group consisting of present genus and Certhidea, Platyspiza and Camarhynchus, known collectively as “Darwin’s finches”, is allied to the tanagers (Thraupidae), being closest to Coereba, Tiaris and several Caribbean genera. A form G. nebulosa was described in 1837 from two specimens, one from Floreana (Charles); relationships uncertain, but, if this is conspecific with present species, name nebulosa would have priority; nebulosa has been considered a synonym of G. fortis. Relationship of present species to other members of genus has always been troubled (hence the name difficilis); hybridizes occasionally with G. conirostris. Considerable differences exist in habits, ecology, size, and bill shape among its different populations. Recent genetic work suggests that interior island populations, which are restricted to highlands on Pinta, Fernandina (Narborough) and Santiago (James), form a well-supported clade which may be only distantly related to others in genus, although, from current data, exact relationship not clear. Present species may warrant division into more than one species, e.g. has been suggested that race septentrionalis merits elevation to species rank. Also, Genovesa population, currently included in nominate, appears genetically distantly related to Pinta population, and it may be better to resurrect name acutirostris for it; indeed, Genovesa population seems genetically closer to other members of genus, suggesting that it should be removed altogether from present species. Full review required. Three subspecies currently recognized.