Melanie
Well-known member
From the upcoming IOC (August 23, 2018)
Subject: *
Morphology, Ecomorphology and Development
Presentation Type: *
Poster
Title of Abstract: *
Morphological diversity in extinct Hawaiian Crows (Corvus)
Authors:
Helen F. James
Smithsonian Institution, Washington, DC, USA
Abstract *
Holocene fossils of large crows (genus Corvus) are known from most of the major Hawaiian Islands, with up to three species recorded on a single island (the island of Hawaii). The fossils represent two extinct (Corvus viriosus, C. impluviatus) and one extant (Hawaiian Crow, C. hawaiiensis) species, plus one or more undescribed species. I assess the morphological diversity in Hawaiian Corvus using comparative osteology and morphometrics. The Hawaiian corvids are comparatively large in body size and disparate in the structure of the maxilla and mandible. Corvus impluviatus had a distinctly domed maxilla and curved tomial crests, whereas C. viriosus and similar fossil forms had long, straight and narrow bills. The recent discovery that the Hawaiian Crow can learn to use tools in captivity in a manner similar to the New Caledonian Crow (Corvus moneduloides) raises the possibility that the extinct Hawaiian straight-billed crows were tool users. A unique adaptation within Corvus was displayed by an undescribed species of crow from the island of Hawaii, which had a bony buttress on the caudal part of the mandible similar to that observed in New World jays (i.e., Aphelocoma) and the Akiapolaau (Hemignathus wilsoni), a Hawaiian honeycreeper. The buttress presumably functioned to stabilize the mandibular articulation during hammering or pounding with the lower mandible, a behavior that the extant Hawaiian Crow employs to open large, hard seeds. It remains to be discovered whether the Hawaiian species of Corvus, with their high morphological diversity in the feeding apparatus, belonged to a single evolutionary radiation.
https://www.iocongressabstracts.com/abstract_summary.php?mode=public&abs_id=2085
Subject: *
Morphology, Ecomorphology and Development
Presentation Type: *
Poster
Title of Abstract: *
Morphological diversity in extinct Hawaiian Crows (Corvus)
Authors:
Helen F. James
Smithsonian Institution, Washington, DC, USA
Abstract *
Holocene fossils of large crows (genus Corvus) are known from most of the major Hawaiian Islands, with up to three species recorded on a single island (the island of Hawaii). The fossils represent two extinct (Corvus viriosus, C. impluviatus) and one extant (Hawaiian Crow, C. hawaiiensis) species, plus one or more undescribed species. I assess the morphological diversity in Hawaiian Corvus using comparative osteology and morphometrics. The Hawaiian corvids are comparatively large in body size and disparate in the structure of the maxilla and mandible. Corvus impluviatus had a distinctly domed maxilla and curved tomial crests, whereas C. viriosus and similar fossil forms had long, straight and narrow bills. The recent discovery that the Hawaiian Crow can learn to use tools in captivity in a manner similar to the New Caledonian Crow (Corvus moneduloides) raises the possibility that the extinct Hawaiian straight-billed crows were tool users. A unique adaptation within Corvus was displayed by an undescribed species of crow from the island of Hawaii, which had a bony buttress on the caudal part of the mandible similar to that observed in New World jays (i.e., Aphelocoma) and the Akiapolaau (Hemignathus wilsoni), a Hawaiian honeycreeper. The buttress presumably functioned to stabilize the mandibular articulation during hammering or pounding with the lower mandible, a behavior that the extant Hawaiian Crow employs to open large, hard seeds. It remains to be discovered whether the Hawaiian species of Corvus, with their high morphological diversity in the feeding apparatus, belonged to a single evolutionary radiation.
https://www.iocongressabstracts.com/abstract_summary.php?mode=public&abs_id=2085
