Robust crow | |
---|---|
The holotype skeleton of C. viriosus. | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Passeriformes |
Family: | Corvidae |
Genus: | Corvus |
Species: | †C. viriosus |
Binomial name | |
†Corvus viriosus Olson & James, 1991 | |
The robust crow or slender-billed crow (Corvus viriosus) was a species of large, raven-sized crow that was endemic to the islands of Oahu and Molokai in the Hawaiian Islands during the Holocene. C. viriosus was frugivorous and was adapted for this with a long, slender bill. It was pushed to extinction due to the arrival of people and pests like rats.
The specific name viriosus comes from the Latin word viriosus meaning "robust" and "strong" after the species' larger size when compared to Corvus hawaiiensis and the sturdy construction of the holotype's cranium and mandible. [1]
Although it may have coexisted with humans, the first recorded fossils of Corvus viriosus were collected by Storrs L. Olson, an American ornithologist who was working for the National Museum of Natural History, USA at the time, on July 26, 1977, from a flooded cavern in Barbers Point, Oahu, Hawaiian islands, the fossils dating to the Quaternary. [2] [1] The fossils from Barbers Point consisted of a single, incomplete skeleton (USNM 386435) that included a partial skull, mandible, and several postcranial elements that were found on the floor of the cavern near a specimen of the related Corvus impluviatus . Another specimen consisting only of a fragmentary skull and partial mandible of C. viriosus that was found on the Hawaiian island Molokai was also referred to C. viriosus. C. viriosus was not mentioned in a published scientific article until 1982 when Olson and fellow USNM ornithologist, Helen F. James, who nicknamed it the "slender-billed species", [3] but it was properly named C. viriosus by the two in 1991, with the Oahu skeleton (USNM 386435) designated the holotype, name specimen, and the Molokai fossils (BBM-X 148156) were made the paratype, another specimen that is part of the type series of specimens. [1]
The geographic location and the close similarities between Hawaiian Corvus species suggests that all species originated from a single common ancestor that settled in Hawaii, as hypothesized by Olson & James (1991). However, the two stated that this ancestor, as well as the ancestor of Hawaiian ravens, was not from North America and instead came from Australasia. [1]
Corvus viriosus was a large species of Corvus with a long, straight bill, deep mandibular ramus, and short tarsometatarsus compared to other species like C. meeki and C. woodfordi . The bill is straighter and has a more narrow dorsal nasal bar compared to C. woodfordi and also a smaller interorbital fenestra with a less elongate narial opening compared to C. macrorhynchus, C. corax , and several other species. C. viriosus also differs from the former species in that the maxillary rostrum is less arched anteriorly; C. viriosus also had a deeper bill, broader nasal bar, and more ossified nasal cavities than C. corax. C. moriorum, another Corvus species, has a larger cranial fenestra, less ossified nasal cavities, shallower mandibular ramus, and a smaller articular mandible end than C. viriosus. C. viriosus differs from the other Hawaiian species C. hawaiiensis and C. impluviatus in that its bill is longer, straighter, less deep, and has a more pronounced excavation of the ventral maxilla. The nasal bars were also narrower, the mandibular symphysis was longer, and the tomial crest, or cutting edge, of the mandible was straighter. C. viriosus has rounded posterior mandibular fossae, or openings, the frontals are less broad, the postorbital processes are slimmer, and the transpalatine process is square tipped, while it is broad and rounded in C. hawaiiensis and C. impluviatus. C. viriosus is like C. hawaiiensis but differs from C. impluviatus in that it has a narrower dorsal nasal bar, a slimmer zygomatic process, a stouter olecranon on the humerus, and a shorter posterior projection on the ilium. In the postcrania, the olecranal fossa on the humerus lacks the deep, rounded pit found in other Hawaiian corvids. [1] [3]
Like other crow species, C. viriosus was an omnivorous bird with a beak adapted to consume different foods, but its larger size suggests that it ate different kinds of food than extant crows or other Hawaiian ones. On the Hawaiian islands that the species lived on, there were no large terrestrial mammals so Corvus and other birds filled the empty ecological role. C. viriosus was primarily a frugivore and possibly are seeds as well based on its classification and morphology, thought detailed analysis of its diet has not been conducted. The slender and curved mandible could have been used for easier frugivory, as in modern finches and crows. [4]
Corvus viriosus lived on the Hawaiian Islands of Oahu and Molokai, two of the central islands in the archipelago, which had lush, high-elevation forests on the mountainous areas and sea cliffs. The lower parts of the islands were much drier and had their own distinct flora and fauna, but many of the native species that lived in the lowlands have gone extinct due to human colonization. [5] C. viriosus lived only in the lowlands and large sand dunes by the beaches, while many other bird species lived in the forests, suggesting niche partitioning between birds on the island. [6]
By the time Europeans arrived in the Hawaiian Islands in 1778, C. viriosus and many other Hawaiian crow species had gone extinct, the only extant native Corvus species being C. hawaiiensis. Most extinct Hawaiian bird species, including C. viriosus, went extinct likely due to hunting and habitat destruction by Polynesian humans, who first colonized the islands around 1000 CE, and also brought animals that possibly hunted the birds to extinction after the Polynesians imported them in the 18th century. [7] [3] Although hunting by humans and imported animals played a role, the destruction of habitats by Polynesians, usually by fire, to make space for agriculture was likely the cardinal factor in the species’ extinction. [8] This is supported not only by fossil and archaeological evidence, but also writings by British explorers like David Nelson describe extensive deforestation in the lowlands that C. viriosus inhabited. [9] [8] At the site of the holotype's discovery in Barbers Point, Oahu, charcoal from a hearth and fossils of several animals that had been imported such as bones of the Pacific rat and shells from land snails were unearthed and dated to as recently as 770 CE. [6] [10] Bones of cooked native Hawaiian birds also suggest that birds were regularly consumed and cooked by steaming. [3]
The Hawaiian crow or ʻalalā is a species of bird in the crow family, Corvidae, that is currently extinct in the wild, though reintroduction programs are underway. It is about the size of the carrion crow at 48–50 cm (19–20 in) in length, but with more rounded wings and a much thicker bill. It has soft, brownish-black plumage and long, bristly throat feathers; the feet, legs, and bill are black. Today, the Hawaiian crow is considered the most endangered of the family Corvidae. They are recorded to have lived up to 18 years in the wild, and 28 years in captivity. Some Native Hawaiians consider the Hawaiian crow an ʻaumakua.
The gray crow, formerly known as the bare-faced crow, is about the same size as the Eurasian carrion crow but has somewhat different proportions and quite atypical feather pigmentation during the juvenile phase for a member of this genus.
Located about 2,300 miles (3,680 km) from the nearest continental shore, the Hawaiian Islands are the most isolated group of islands on the planet. The plant and animal life of the Hawaiian archipelago is the result of early, very infrequent colonizations of arriving species and the slow evolution of those species—in isolation from the rest of the world's flora and fauna—over a period of at least 5 million years. As a consequence, Hawai'i is home to a large number of endemic species. The radiation of species described by Charles Darwin in the Galapagos Islands which was critical to the formulation of his theory of evolution is far exceeded in the more isolated Hawaiian Islands.
The white-billed crow is a member of the crow family found on the Solomon Islands.
A crow is a bird of the genus Corvus, or more broadly, a synonym for all of Corvus. The word "crow" is used as part of the common name of many species. The related term "raven" is not linked scientifically to any certain trait but is rather a general grouping for larger-sized species of Corvus.
The ʻāmaui or Oahu thrush was a subspecies of the olomaʻo endemic to the island of Oahu. It was the first member of its genus to become extinct, c. 1850. Some taxonomic authorities consider it a distinct species, but the International Ornithological Congress presently classifies it as a subspecies of M. lanaiensis.
The New Zealand raven was native to New Zealand, but has been extinct since the 16th century. There were three subspecies: the North Island raven, South Island raven, and Chatham raven from the Chatham Islands.
Ciridops is an extinct genus of Hawaiian honeycreeper species that occurred in prehistoric and historic times on the Hawaiian islands of Hawaii, Molokai, Kauai and Oahu. This genus was created in 1892 by Alfred Newton in an article published by the journal Nature on the basis of the ʻula-ʻai-hawane, which was named Fringilla anna by Sanford B. Dole in 1879.
The Lānaʻi hookbill is an extinct species of Hawaiian honeycreeper. It was endemic to the island of Lānaʻi in Hawaiʻi, and was last seen in the southwestern part of the island. George C. Munro collected the only known specimen of this species in 1913, which is housed in the Bernice P. Bishop Museum in Honolulu, and saw the species only twice more, once in 1916 and for a final time in 1918. No other sightings have been reported. They inhabited montane dry forests dominated by ʻakoko and ōpuhe. The Lānaʻi hookbill was monotypic within the genus Dysmorodrepanis and had no known subspecies. Its closest relative is believed to be the ʻōʻū, and some early authors suggested that the Lānaʻi hookbill was merely a deformed ʻōʻū. The Lānaʻi hookbill was a plump, medium-sized bird with greenish olive upperparts and pale whitish yellow underparts. It also had a yellow or white superciliary line and a white chin and throat. The wings also had a distinctive and conspicuous white wing patch. The hookbill's distinguishing characteristic was its heavy, parrotlike bill, which had the mandibles hooking sharply towards each other, leaving a gap between them when the beak was closed.
The highland finch is an extinct member of the Fringillidae and a Hawaiian honeycreeper which is known only from a few bones found in caves. It is the only member of the genus Orthiospiza. It was endemic to the high-elevation areas of Mount Haleakalā on the Hawaiian island of Maui. It has been speculated that they were pushed to extinction because of habitat loss. It is known only from fossil remains and likely became extinct before the first Europeans arrived in 1778.
The Kauai finch is an extinct bird in the genus Telespiza of the family Fringillidae. It was endemic to the Hawaiian islands of Kauai and Oahu. It is only known from fossil remains and likely became extinct before the first Europeans visited Hawaii in 1778.
The primitive koa finch is an extinct species of Hawaiian honeycreeper in the subfamily Carduelinae of the family Fringillidae. It is known from fossils on the islands of Maui and Oʻahu in Hawaii.
The great Oʻahu rail or great Oʻahu crake is a little-known extinct bird species from Oʻahu, Hawaiʻi, attested only by a few subfossil bones. The holotype is a right tarsometatarsus found in a flooded sinkhole on the ʻEwa Plain near Barbers Point, the southwestern tip of Oʻahu.
The great Maui crake or great Maui rail is an extinct bird species from Maui, Hawaiian Islands, known only from subfossil bones. The holotype are the bones of one almost-complete skeleton, found in Auwahi Cave on the lower southern slope of Haleakalā at 1,145 m AMSL. Its first remains, however, were recovered in 1972 and/or 1974 from lower Waihoi Valley further east and less than half as far uphill.
The high-billed crow or deep-billed crow was a species of large, raven-sized crow that was endemic to the island of Oahu in the Hawaiian Islands. It was pushed to extinction due to the arrival of people and pests like rats.
Talpanas lippa, the Kauaʻi mole duck, is an extinct species of duck. It was first described by Andrew N. Iwaniuk, Storrs L. Olson, and Helen F. James in the journal Zootaxa in November 2009. It is the only known member of the genus Talpanas. It was endemic to the Hawaiian island of Kauai where the fossil remains were unearthed in the Makauwahi Cave, Maha‘ulepu. The archaeological association of the bones is about 6000 years BP.
The wood harrier or mime harrier is an extinct bird of prey which lived in Hawaii during the Holocene. This small, short-winged harrier inhabited the forests of Molokai and Oahu where it presumably hunted for small birds and insects.
Xestospiza fastigialis is an extinct species of bird with a ridge-shape bill that was described on the basis of fossils. It was possibly an insectivore, populating the Hawaiian Islands of Oahu, Molokai and Maui.