The
birdBirds are winged, bipedal, endothermic , vertebrate animals that lay eggs. There are around 10,000 living species, making them the most numerous tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Birds range in size from the Bee Hummingbird to the ...
familyIn biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus...
Sulidae comprises the
gannetGannets are seabirds in the family Sulidae, closely related to the boobies.The gannets are large black and white birds, with long pointed wings and long bills. Northern gannets are the largest seabirds in the North Atlantic, with a wingspan of up to 2 metres...
s and
boobiesA booby is a seabird in the Sula genus, part of the Sulidae family. Boobies are closely related to the gannets , which were formerly included in Sula....
. Collectively called
sulidas, they are medium-large coastal
seabirdSeabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s that plunge-dive for
fishA fish is any aquatic vertebrate animal that is typically ectothermic , covered with scales, and equipped with two sets of paired fins and several unpaired fins...
and similar prey. The
speciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
in this family are often considered
congenerA congener has several different meanings depending on the field in which it is used. Colloquially, it is used to mean a person or thing like another, in character or action.-Biology:...
ic in older sources, placing all in the
genusIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
Sula. However,
Sula (true boobies) and
Morus (gannets) can be readily distinguished by
morphologicalIn biology morphology is the form, structure and configuration of an organism.This includes aspects of the outward appearance as well as the form and structure of the internal parts like bones and organs...
and
behavioralEthology is the scientific study of animal behavior, and a sub-topic of zoology....
and
DNA sequenceA DNA sequence or genetic sequence is a succession of letters representing the primary structure of a real or hypothetical DNA molecule or strand, with the capacity to carry information as described by the central dogma of molecular biology....
characters.
Abbott's BoobyAbbott’s Booby is a large endangered seabird of the gannet family, Sulidae. Found normally only on and around Christmas Island Abbott’s Booby (Papasula abbotti) is a large endangered seabird of the gannet family, Sulidae. Found normally only on and around Christmas Island Abbott’s Booby...
(
Papasula) stands apart from both in these respects and appears to be a distinct and ancient lineage, maybe closer to the gannets than to the true boobies.
Description
Sulids measure about in length and have a wingspan of about . They have long, narrow and pointed wings, and a quite long, graduated and rather
lozengeA lozenge , often referred to as a diamond, is a form of rhombus. The definition of lozenge is not strictly fixed, and it is sometimes used simply as a synonym for rhombus. Most often, though, lozenge refers to a thin rhombus—a rhombus with acute angles of 45°...
-shaped tail whose outer feathers are shorter than the central ones. Their flight muscles are rather small to allow for the small
cross sectionIn geometry, a cross-section is the intersection of a body in 2-dimensional space with a line, or of a body in 3-dimensional space with a plane, etc. More plainly, when cutting an object into slices one gets many parallel cross-sections....
required for plunge-diving, and thus their
wing loadingIn aerodynamics, wing loading is the loaded weight of the aircraft divided by the area of the wing. The faster an aircraft flies, the more lift is produced by each unit area of wing, so a smaller wing can carry the same weight in level flight, operating at a higher wing loading. Correspondingly,...
is high. Consequently, they are very
streamlinedA streamliner is any vehicle that incorporates streamlining to produce a shape that provides less resistance to air. The term is most often applied to certain high-speed railway trainsets of the 1930s to 1950s, and to their successor "bullet trains". Less commonly, the term is applied to fully...
, reducing
dragIn fluid dynamics, drag refers to forces that oppose the relative motion of an object through a fluid . Drag forces act in a direction opposite to the oncoming flow velocity...
, so their bodies are "
torpedoThe modern torpedo is a self-propelled explosive projectile weapon, launched above or below the water surface, propelled underwater toward a target, and designed to detonate on contact or in proximity to a target...
-shaped" as well as somewhat flat.
They have stout legs and webbed feet, with the web connecting all four toes. In some species the webs are brightly colored and used in
courtship displayCourtship display is a special, sometimes ritualised, set of behaviours which some animals perform as part of courtship. Courtship behaviours can include special calls, postures, and movements, and may involve special plumage, bright colours or other ornamentation. A good example is the 'dancing'...
s. The bill is usually conspicuously colored, long, deep at the base, and pointed, with saw-like edges. The upper mandible curves down slightly at the tip and can be moved upward to accept large prey. To keep water out during plunges, the nostrils enter into the bill rather than opening to the outside directly. he eyes are angled forward, and provide a wider field of
binocular visionBinocular vision is vision in which both eyes are used together. The word binocular comes from two Latin roots, bini for double, and oculus for eye. Having two eyes confers at least four advantages over having one. First, it gives a creature a spare eye in case one is damaged. Second, it gives a...
than in most other birds.
The
plumagePlumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
is either all-white (or light brownish or greyish) with dark wingtips and (usually) tail, or at least some dark brown or black above with white underparts; gannets have a yellowish hue to the head. The face usually has some sort of black markings, typically on the lores. Unlike their relatives (the
darterThe darters or snakebirds are mainly tropical waterbirds in the family Anhingidae. There are four living species, three of which are very common and widespread while the fourth is rarer and classified as near-threatened by the IUCN. The term "snakebird" is usually used without any additions to...
s and
cormorantThe bird family Phalacrocoracidae is represented by some 40 species of cormorants and shags. Several different classifications of the family have been proposed recently, and the number of genera is disputed.- Names :...
s), sulids have a well-developed preen gland whose waxy secretions they spread on their feathers for waterproofing and pest control. They
moultIn biology, moulting signifies the manner in which an animal routinely casts off a part of its body , either at specific times of year, or at specific points in its life-cycle.Moulting can involve the epidermis , pelage In biology, moulting (or molting, also known as sloughing, shedding or for...
their tail feathers irregularly and the
flight featherFlight feathers are the long, stiff, asymmetrically shaped, but symmetrically paired feathers on the wings or tail of a bird; those on the wings are called remiges while those on the tail are called rectrices . Their primary function is to aid in the generation of both thrust and lift, thereby...
s of their wings in stages, so that starting at the first moult, they always have some old feathers, some new ones, and some partly grown ones. Moult as a response to periods of
stress- Mechanical :* Stress , the average amount of force exerted per unit area* Yield stress, the stress at which a material begins to deform plastically* Compressive stress, the stress applied to materials resulting in their compaction- Biological :...
has been recorded.
Distribution and ecology
The sulids are distributed mainly in tropical and subtropical waters. Particularly gannets, however, are found in
temperateIn geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally mild, rather than extreme hot or cold. But in continental areas, such as central North America the variations between summer...
regions too. These birds are not truly pelagic
seabirdSeabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s like the related
ProcellariiformesProcellariiformes is an order of seabirds that comprises four families: the albatrosses, procellariids, storm-petrels and diving petrels. Formerly called Tubinares and still called tubenoses in English, they are often referred to collectively as the petrels, a term that has been applied to all...
, and usually stay rather close to the coasts. But the abundant colonies of sulids that exist on many Pacific islands suggest that they are not infrequently blown away from their home range by
stormA storm is any disturbed state of an astronomical body's atmosphere, especially affecting its surface, and strongly implying severe weather...
s, and can wander for long distances in search of a safe place to land if need be.
All
speciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
feed entirely at sea, mostly on mid-sized
fishA fish is any aquatic vertebrate animal that is typically ectothermic , covered with scales, and equipped with two sets of paired fins and several unpaired fins...
and similarly-sized
marineMarine or Marines may refer to:*Marine , a general term for things relating to the sea or ocean*Marine , a member of the military in an infantry or amphibious force under the authority of a navy, or in several cases, of an independent amphibious force **The military rank of "Marine", being the...
invertebrateAn invertebrate is an animal without a vertebral column. The group includes 95% of all animal species — all animals except those in the Chordate subphylum Vertebrata ....
s (e.g.
cephalopod{Taxobox| name = Cephalopods| fossil_range = | image = Tafel 054 300.jpg| image_caption = A variety of cephalopod forms from Ernst Haeckel's 1904 Kunstformen der Natur| regnum = Animalia| image_width = 220px| phylum = Mollusca| classis = Cephalopoda...
s). Many species feed communally, and some species follow fishing boats to scavenge discarded bycatch and
chumChumming is the practice of luring animals, usually fish or shark, by throwing "chum" into the water. Chum often consists of fish parts and blood, which attracts fish, and particularly sharks due to their keen sense of smell....
. The typical hunting behavior is a dive from mid-air, taking the bird a meter or two under water. If prey manages to escape the diving birds at first, they may give chase using their legs and wings for underwater swimming.
As noted above, the
behavioralEthology is the scientific study of animal behavior, and a sub-topic of zoology....
traits of gannets and boobies differ considerably, but the Sulidae as a whole are characterized by several behavioral synapomorphies: Before taking off, they will point the bill upwards (gannets) or forward (boobies). After landing again, they point downwards with the bill. And in response to a threat, they will not attack but shake their heads and point the bill towards the intruder.
Reproduction
All sulids breed in colonies. Males examine the colony area in flight and then pick a nest site, which they defend by fighting and by territorial
displayDisplay is a form of animal behaviour, linked to survival of the species in various ways. One example of display used by some species can be found in the form of courtship, with the male usually having a striking feature that is distinguished by colour, shape or size, used to attract a female...
s. Males then advertise to females by a special display and call. The display behaviour is characteristic, though not as diverse as the numerous variations found among the
cormorantThe bird family Phalacrocoracidae is represented by some 40 species of cormorants and shags. Several different classifications of the family have been proposed recently, and the number of genera is disputed.- Names :...
s; it typically includes the male shaking its head. Females search the colony in flight and on foot for a mate. Once they select males, pairs maintain their bonds by preening each other and by frequent copulation.
The
clutchA clutch of eggs refers to all the eggs produced by birds or reptiles often at a single time, particularly those laid in a nest.-Size:Clutch size will differ greatly between species, sometimes even within the same genus. It may also differ within the same species due to many factors including...
is typically 2
eggsIn most birds and reptiles, an egg is the zygote, resulting from fertilization of the ovum. To enable incubation the egg is usually kept within a favourable temperature range as it nourishes and protects the growing embryo. When the embryo is adequately developed it breaks out of the egg in the...
. The eggs are unmarked (but may become stained by
debrisDebris is a word used to describe the remains of something that has been otherwise destroyed. The singular form of debris is debris.Depending on context, debris can refer to a number of different things.- Geological :...
in the nest), whitish, pale blue, green or pink, and have a coating that resembles
limeLime is a general term for calcium-containing inorganic materials, in which carbonates, oxides and hydroxides predominate. Strictly speaking, lime is calcium oxide or calcium hydroxide. It is also the name for a single mineral of the CaO composition, occurring very rarely...
. Their weight ranges from 3.3 percent to 8 percent of the female's. Incubation lasts 42 to 55 days, depending on the species. Both sexes incubate; like their relatives they do not have
brood patchthumb|250px|Brood patch of [[Sand Martin]]A brood patch is a patch of featherless skin that is visible on the underside of birds during the nesting season. This patch of skin is well supplied with blood vessels at the surface making it possible for the birds to transfer heat to their eggs when...
es, but their feet become
vascularIn zoology, "vascular" means "related to blood vessels", which are part of the Circulatory system. An organ or tissue that is vascularized is heavily endowed with blood vessels and thus richly supplied with blood....
ized and hot, and the birds place the eggs under the webs. Eggs lost during the first half of incubation are replaced.
At hatching, parents move the eggs and then the hatchlings to the tops of their webs. The young hatch naked, but soon develop white down. They beg by touching the parent's bill and take regurgitated food straight from its gape. At first at least one parent is always in attendance of the
altricialAltricial, meaning "requiring nourishment", refers to a pattern of growth and development in organisms which are incapable of moving around on their own soon after hatching or being born...
young; after two weeks, both parents leave the nest unguarded at times while they go fishing. The times for the chicks to fledge and to become independent of their parents depend greatly on the food supply. Rarely does more than one chick survive to maturity, except in the
Peruvian BoobyThe Peruvian Booby, Sula variegata, is an endemic bird of the Peruvian current whose distribution is restricted to the west coast of South America from Punta Pariñas in Peru to Concepción in Chile . It is the second most abundant seabird species that inhabits the Peruvian Coast and the second...
(
Sula variegata) – which has the biggest clutch (two to four eggs) –, and less often in the
Blue-footed BoobyThe Blue-footed Booby is a bird in the Sulidae family which comprises ten species of long-winged seabirds.The natural breeding habitat of the Blue-footed Booby is tropical and subtropical islands off the Pacific Ocean, most famously, the Galápagos Islands, Ecuador.-Taxonomy:The name “booby” comes...
(
S. nebouxii) .
SiblicideSiblicide , the death of an individual by its close relatives may occur directly between siblings or indirectly across the parent-offspring relationship and is seen to have beneficial indirect results for the genetic viability of a population or direct results for the recipient individuals.Cattle...
by the stronger of two chicks is frequent.
Systematics and evolution
Sulids are related to a number of other
aquaticAquatic means relating to water; living in or near water or taking place in water.Aquatic may also refer to:* Aquatic animal, either vertebrate or invertebrate, which lives in water for most or all of its life...
birds which all lack external
nostrilA nostril is one of the two channels of the nose, from the point where they bifurcate to the external opening. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation...
s and a
brood patchthumb|250px|Brood patch of [[Sand Martin]]A brood patch is a patch of featherless skin that is visible on the underside of birds during the nesting season. This patch of skin is well supplied with blood vessels at the surface making it possible for the birds to transfer heat to their eggs when...
, but have all four toes webbed and a gular sac. The closest living relatives of the Sulidae are the Phalacrocoracidae (cormorants and shags) and the Anhingidae (darters). The latter are somewhat intermediate between sulids and cormorants, but (like many cormorants) they are
freshwaterFreshwater is naturally occurring water on the surface such as bogs, ponds, lakes, rivers and streams, and underground in aquifers and underground rivers. Freshwater is characterized by having low concentrations of dissolved salts...
birds in a
cladeA clade is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants.[The term "monophyletic group" is used in this article...]
containing otherwise
seabirdSeabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s, and also symplesiomorphic with sulids but synapomorphic with cormorants in some other respects. Thus, the Sulidae seem to be the oldest and most distinct lineage of those three, which are united in a suborder Sulae. Therein, the Sulidae are typically placed simply as a
familyIn biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus...
; sometimes a
superfamilyThe term superfamily is used to describe several different concepts in different scientific fields:* Superfamily : a level of biological classification* Superfamily : in comparative linguistics, another term for macrofamily...
Suloidea is recognized, wherein some of the primitive prehistoric forms (e.g.
Empheresula,
Eostega and
Masillastega) are placed as basal lineages distinct from the living Sulidae. However, the proposed family
Pseudosulidae (or
Enkurosulidae) is almost certainly invalid.
The Sulae were traditionally included in the "
PelecaniformesThe Pelecaniformes are a order of medium-sized and large waterbirds found worldwide. As traditionally – but erroneously – defined, they encompass all birds that have feet with all four toes webbed. Hence, they were formerly also known by such names as totipalmates or steganopodes...
" in its obsolete paraphyletic circumscription. But
pelicanA pelican is a large water bird with a distinctive pouch under the beak, belonging to the bird family Pelecanidae.Along with the darters, cormorants, gannets, boobies, frigatebirds, and tropicbirds, pelicans make up the order Pelecaniformes. Modern pelicans are found on all continents except...
s, the namesake family of the Pelecaniformes, are actually closer related to
storkStorks are large, long-legged, long-necked wading birds with long stout bills, belonging to the family Ciconiidae. They are the only family in the biological order Ciconiiformes, which was once much larger and held a number of families....
s than to the sulids and allies. In recognition of this, the Sulae have been proposed for separation in a new
orderIn scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Phalacrocoraciformes, which also includes the
frigatebirdThe frigatebirds are a family, Fregatidae, of seabirds. There are five species in the single genus Fregata. They are also sometimes called Man of War birds or Pirate birds. Since they are related to the pelicans, the term "frigate pelican" is also a name applied to them...
s (Fregatidae) as well as one or more prehistoric lineages that are entirely extinct today.
There are three living
generaGenera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
. One is
monotypicIn biology, a monotypic taxon is a taxonomic group with only one type. The usage differs slightly between botany and zoology:In botany, a monotypic taxon is a taxon that has only one species: Ginkgo is a monotypic genus, while Ginkgoaceae is a monotypic family...
, another has but a few species, while the third contains about 65% of all living sulids:
- Sula (boobies, 6 species)
- Papasula (Abbott's Booby)
- Morus (gannets, 3 species)
Evolution and fossil genera
The
fossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
record of sulids is quite extensive due to the many
MioceneThe Miocene is a geological epoch of the Neogene period and extends from about 23.03 to 5.33 million years before the present . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the...
/
PlioceneThe Pliocene epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present....
forms that have been recovered. But the lineage of sulids extends back to the
EoceneThe Eocene epoch, lasting from 55.8 ± 0.2 to 33.9 ± 0.1 Ma , is a major division of the geologic timescale and the second epoch of the Palaeogene period in the Cenozoic era. The Eocene spans the time from the end of the Paleocene epoch to the beginning of the Oligocene epoch. The start of the...
, and all things (such as the Early Eocene
frigatebirdThe frigatebirds are a family, Fregatidae, of seabirds. There are five species in the single genus Fregata. They are also sometimes called Man of War birds or Pirate birds. Since they are related to the pelicans, the term "frigate pelican" is also a name applied to them...
LimnofregataLimnofregata is an extinct genus of primitive frigatebird. The two known species were described after fossils from the Early Eocene Green River Formation of Wyoming. A number of good complete and partial skeletons, some with feather impressions, are known of the type species, and L...
) considered, the sulids seem to have diverged from the lineage leading to cormorants and darters around 50 million years ago (Ma), perhaps a bit earlier. The initial
evolutionary radiationAn evolutionary radiation is an increase in taxonomic diversity or morphological disparity, due to adaptive change or the opening of ecospace. Radiations may affect one clade or many, and be rapid or gradual; where they are rapid, and driven by a single lineage's adaptation to their environment,...
formed a number of
generaGenera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
which are now completely extinct, such as the
freshwaterFreshwater is naturally occurring water on the surface such as bogs, ponds, lakes, rivers and streams, and underground in aquifers and underground rivers. Freshwater is characterized by having low concentrations of dissolved salts...
Masillastega (which, as noted above, might not have been a modern-type sulid) or the bizarre
Rhamphastosula (which had a bill shaped like an
aracariThe aracaris are medium-sized toucans in the genus Pteroglossus. As denoted by the presence of the cedilla on the C , the proper pronunciation is "ahr-uh-SAHR-ee" not "ahr-uh-KAR-ee"....
's). The modern genera
evolveEvolve may refer to:*Evolve, as in Evolution.*Evolve on The History Channel*Evolve Festival, an annual music and cultural festival held in Nova Scotia, Canada.*Evolve Cars, an after-market manufacturer of sport-parts for Volvo cars....
d (like many other living genera of birds) around the
OligoceneThe Oligocene is a geologic epoch of the Paleogene period and extends from about 33.9 million to 23 million years before the present. As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
-Miocene boundary about 23 Ma.
Microsula, which lived during that time, seems to have been a primitive booby that still had many symplesiomorphies with gannets. Like the other Phalacrocoraciformes, the sulids originated probably in the general region of the Atlantic or western Tethys Sea – probably the latter rather than the former, given that their earliest fossils are abundant in
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
but absent from the well-studied contemporary
AmericaThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
n deposits.
Prehistoric sulids (or suloids) only known from
fossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
s are:
- Masillastega (Early Eocene of Messel, Germany) – may belong in Eostega
- Eostega (Late Eocene of Cluj-Manastur, Romania) – may include Masillastega
- Sulidae gen. et sp. indet. (Thalberg Late Oligocene of Germany) – Empheresula?
- Sulidae gen. et sp. indet. (Late Oligocene of South Carolina, USA) – Microsula?
- Empheresula (Late Oligocene of Gannat, France – Middle Miocene of Steinheimer Becken, Germany) – including "Sula" arvernensis, Parasula
- Microsula (Late Oligocene of South Carolina, USA – Grund Middle Miocene of Austria) – may belong in Sula, includes "Sula" avita, "S." pygmaea, Enkurosula, Pseudosula
- Sarmatosula (Middle Miocene of Credinţa, Romania)
- Miosula (Late Miocene of California)
- Palaeosula (Early Pliocene? of California)
- Rhamphastosula (Pisco Early Pliocene of SC Peru)
- Sulidae gen. et sp. indet. (Late Pliocene of Valle di Fine, Italy) – Morus?
For prehistoric
speciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
of the extant
generaGenera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
, see the genus articles.
The Early Oligocene
Prophalacrocorax ronzoni of Ronzon (
FranceFrance , officially the French Republic , is a country located in Western Europe, with several overseas islands and territories located on other continents. Metropolitan France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean...
) was variously placed in the seaduck genus
MergusMergus is the genus of the typical mergansers, fish-eating ducks in the seaduck subfamily . The Hooded Merganser, often termed Mergus cucullatus, is not of this genus but closely related...
, in
Sula, and – after a distinct genus was established for it – in the Phalacrocoracidae. While it is quite likely to belong in the Sulae and may have been an ancient sulid (or suloid), of the three placements explicitly proposed none seems to be correct.
External links