Dow's puffin (''Fratercula dowi'') is an
extinct
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
seabird in the
auk
Auks or alcids are birds of the family Alcidae in the order Charadriiformes. The alcid family includes the Uria, murres, guillemots, Aethia, auklets, puffins, and Brachyramphus, murrelets. The family contains 25 extant or recently extinct speci ...
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
described in 2000 from
subfossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
remains found in the
Channel Islands of California
The Channel Islands () are an eight-island archipelago located within the Southern California Bight in the Pacific Ocean, off the coast of California. They define the Santa Barbara Channel between the islands and the California mainland. The ...
. It was approximately as large as the modern
horned puffin and its beak appeared to have been an intermediate between the
rhinoceros auklet
The rhinoceros auklet (''Cerorhinca monocerata'') is a seabird and a close relative of the puffins. It is the only extant species of the genus ''Cerorhinca''. Given its close relationship with the puffins, the common name rhinoceros puffin has b ...
and the
horned puffin. It lived during the Late Pleistocene and Early Pleistocene on the Channel Islands, where it nested alongside the
ancient murrelet
The ancient murrelet (') is a bird in the auk family. The English term "murrelet" is a diminutive of "murre", a word of uncertain origins, but which may imitate the call of the common guillemot. Ancient murrelets are called "ancient" because t ...
,
Cassin's auklet and ''
Chendytes lawi''.
History and naming
The first remains of ''Fratercula dowi'' were discovered in late 1986 by G. L. Kennedy and D. R. Muhs. The subfossil, an articulated bird skeleton, was found in a Late Pleistocene
eolianite
Eolianite or aeolianite is any rock formed by the lithification of sediment deposited by aeolian processes; that is, the wind. In common use, however, the term refers specifically to the most common form of eolianite: coastal limestone consisting ...
outcrop on
San Nicolas Island
San Nicolas Island (Spanish: ''Isla de San Nicolás''; Tongva: ''Haraasnga'') is the most remote of the Channel Islands, off Southern California, from the nearest point on the mainland coast. It is part of Ventura County. The island is current ...
. This specimen was found lying on its belly with a bent neck and preserved beak tip. Most of the skull, alongside much of the legs and posterior torso had eroded away but a complete fossil egg was discovered nearby. Initial observations by paleornithologist
Hildegarde Howard regarded this bird to be an
alcid
Auks or alcids are birds of the family Alcidae in the order Charadriiformes. The alcid family includes the murres, guillemots, auklets, puffins, and murrelets. The family contains 25 extant or recently extinct species that are divided into ...
potentially related to the
rhinoceros auklet
The rhinoceros auklet (''Cerorhinca monocerata'') is a seabird and a close relative of the puffins. It is the only extant species of the genus ''Cerorhinca''. Given its close relationship with the puffins, the common name rhinoceros puffin has b ...
. In addition to the San Nicolas specimen, a rich bonebed was discovered on the nearby
San Miguel Island
San Miguel Island ( Chumash: ''Tuqan'') is the westernmost of California's Channel Islands, located across the Santa Barbara Channel in the Pacific Ocean, within Santa Barbara County, California. San Miguel is the sixth-largest of the eight Ch ...
, which yielded over 6.000 alcid bones distinct from the rhinoceros auklet. In 2000, the specimen recovered on San Nicolas Island served as the
holotype
A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
of the new species ''Fratercula dowi'', with several specimens from San Miguel Island being used as
paratypes. In addition to these newer remains, some bones previously assigned to the rhinoceros auklet were also found to have belonged to ''Fratercula dowi'', extending its range to
Santa Rosa Island and possibly even
Anacapa Island. The remains from San Nicolas Island date to the Late Pleistocene, approximately 46.000 to 31.000 years
BP, while those of San Miguel are younger, with the most recent dating to approximately 11.890 years BP. The oldest remains of puffins from the Channel Islands may suggest that the species first appeared 100.000 years BP.
[
The species is named after Ronald J. Dow, who had assisted Kennedy and Muhs to their trips to the ]Channel Islands
The Channel Islands are an archipelago in the English Channel, off the French coast of Normandy. They are divided into two Crown Dependencies: the Jersey, Bailiwick of Jersey, which is the largest of the islands; and the Bailiwick of Guernsey, ...
.[
]
Description
Dow's Puffin is clearly distinguishable from all other extant and extinct puffins of the American west coast by the morphology of the beak, specifically how far it extends dorsally and ventrally. The beak shape is not as narrow as in the modern rhinoceros auklet, but lacking the pronounced expansion seen in the horned puffin.[ As this character may be variable among members of a single species, the diagnosis for ''Fratercula dowi'' was later amended in a Ph. D. dissertation. Neil Adam Smith described several anatomical traits of the ]humerus
The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...
that more clearly distinguish the Channel Islands species from its modern relatives. The distal margin of the humeral head for instance is rounded, something otherwise observed in other auks, while in puffins this region is pointed. The olecranon
The olecranon (, ), is a large, thick, curved bony process on the proximal, posterior end of the ulna. It forms the protruding part of the elbow and is opposite to the cubital fossa or elbow pit (trochlear notch). The olecranon serves as a lever ...
projects in a fashion similar to ''Synthliboramphus
''Synthliboramphus'' is a small genus of seabirds in the auk family from the North Pacific. The genus name ''Synthliboramphus'' is from Ancient Greek ''sunthlibo'', "to compress", and ''rhamphos'', "bill". The English name "Murrelet" is a dimi ...
'' while the ulna
The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...
shows characters otherwise seen in the whiskered auklet and the extinct '' Cerorhinca aurorensis''.
''Fratercula dowi'' is smaller than the tufted puffin, but indistinguishable in size from the rhinoceros auklet or the horned puffin. However ''Fratercula dowi'' appears to have undergone an overall decrease in size throughout its temporal range, with the youngest remains having been found to be smaller than its oldest.[
]
Phylogeny
Phylogenetic analysis of the Fraterculini has recovered that ''Fratercula dowi'' was likely the basalmost species within the genus.[
]
Paleobiology
During the Late Pleistocene ''Fratercula dowi'' coexisted with at least one other species of puffin on San Miguel Island, the tufted puffin which is known from three subfossil bones. Other Pleistocene puffin remains were initially assigned to the rhinoceros auklet, but later found to have either belonged to Dow's puffin or at least to the ''Fratercula'' genus. Besides the tufted puffin, other seabirds found on the Channel Islands include the ancient murrelet
The ancient murrelet (') is a bird in the auk family. The English term "murrelet" is a diminutive of "murre", a word of uncertain origins, but which may imitate the call of the common guillemot. Ancient murrelets are called "ancient" because t ...
and Cassin's auklet.[ Seeing as the remains of these birds were all preserved in sitting positions, it is hypothesized that they died when their nesting burrows caved in. This would suggest that the nesting habits of Dow's puffin are closer to that of the tufted puffin and rhinoceros auklet, while the horned puffin nests in rocky crevices. Typically modern puffins lay a single egg which is attended by both parents, a fact that corresponds well with the single egg discovered in association with the holotype of ''Fratercula dowi''. The egg is also within the size range of modern puffin species, which extends to the eggs discovered on San Miguel Island, even if they lack direct association to skeletal material.][ The flightless seaduck '' Chendytes lawi'' also nested on the island of San Miguel alongside the aforementioned auk species.]
Although modern puffins are generally restricted to more northern latitudes, only occasionally coming as far south as California in the winter, water temperatures during the Pleistocene were notably cooler than they are today. This would explain the presence of a breeding population of ''Fratercula dowi'' on the Channel Islands.[
]
References
{{Taxonbar, from=Q5302592
Fratercula
Natural history of the Channel Islands of California
Pleistocene birds of North America
Pleistocene California
Late Quaternary prehistoric birds
Holocene extinctions
Extinct birds of North America
Fossil taxa described in 2000