Cypselomorphae
Encyclopedia
Cypselomorphae is a clade
of bird
s. It includes the living families
and orders
Caprimulgidae (nightjars, nighthawks and allies), Nyctibiidae (potoos), Apodiformes
(swifts and hummingbirds), as well as the Aegotheliformes (owlet-nightjars) whose distinctness was only recently realized. The Apodiformes (which include the "Trochiliformes" of the Sibley-Ahlquist taxonomy
) and the Aegotheliformes form the Daedalornithes.
In addition, several fossil taxa are tentatively placed here as basal or incertae sedis
The relationships of the Early Eocene Parvicuculus and Procuculus from the southern North Sea
basin are unresolved, but they bear some similarities to cypselomorphs.
The fossil evidence is quite consistent in this group. Over some 20 million years, throughout the Eocene
, the present-day diversity (as well as some entirely extinct lineages) slowly unfolds. By mid-Oligocene, some 30 million years ago, the crown
lineages are present and adapting to their present-day ecological niche
s.
By the distribution of fossils, the Paleogene radiation seems to have originated in Asia
, which at that time became a highly fragmented landscape as the Himalayas
lifted up and the Turgai Strait started to disappear.
The Cypselomorphae are part of the proposed Metaves. The material evidence for this group is very equivocal; the most ancient Cypselomorphae are quite nondescript tree-dwellers but already tend towards peculiarly apomorphic feet, and no Cretaceous
fossils are known that would link them to other "Metaves" such as Mirandornithes
.
Torpor
and other metabolic peculiarities are very frequently found in this group, perhaps more often than in any other bird lineage.
Their shared apomorphies are: ossa maxillaria separated by a large cleft, a mandible with very short pars symphysialis, and rami mandibulae very slender in their distal half.
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s. It includes the living families
Family (biology)
In 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. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
and orders
Order (biology)
In 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...
Caprimulgidae (nightjars, nighthawks and allies), Nyctibiidae (potoos), Apodiformes
Apodiformes
Traditionally, the bird order Apodiformes contained three living families: the swifts , the tree swifts , and the hummingbirds . In the Sibley-Ahlquist taxonomy, this order is raised to a superorder Apodimorphae in which hummingbirds are separated as a new order, Trochiliformes...
(swifts and hummingbirds), as well as the Aegotheliformes (owlet-nightjars) whose distinctness was only recently realized. The Apodiformes (which include the "Trochiliformes" of the Sibley-Ahlquist taxonomy
Sibley-Ahlquist taxonomy
The Sibley-Ahlquist taxonomy is a bird taxonomy proposed by Charles Sibley and Jon Edward Ahlquist. It is based on DNA-DNA hybridization studies conducted in the late 1970s and throughout the 1980s....
) and the Aegotheliformes form the Daedalornithes.
In addition, several fossil taxa are tentatively placed here as basal or incertae sedis
Incertae sedis
, is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...
- Eocypselus (Late Paleocene or Early Eocene)
- Paraprefica (Early Eocene?)
- ArchaeotrogonidaeArchaeotrogonidaeArchaeotrogon is a prehistoric bird genus. Its remains have been found in the Quercy Phosphorites of France, a geological formation containing Late Eocene and Early Oligocene deposits. Archaeotrogon lived some 30-35 million years ago. Not all species described herein may be valid.This genus has...
(Early Eocene of England ?- Late Eocene/Early Oligocene of France) - Hassiavis (Middle Eocene of Messel, Germany) - Archaeotrogonidae?
- Protocypselomorphus (Middle Eocene of Messel, Germany)
The relationships of the Early Eocene Parvicuculus and Procuculus from the southern North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
basin are unresolved, but they bear some similarities to cypselomorphs.
The fossil evidence is quite consistent in this group. Over some 20 million years, throughout the Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
, the present-day diversity (as well as some entirely extinct lineages) slowly unfolds. By mid-Oligocene, some 30 million years ago, the crown
Crown group
A crown group is a group consisting of living representatives, their ancestors back to the most recent common ancestor of that group, and all of that ancestor's descendants. The name was given by Willi Hennig, the formulator of phylogenetic systematics, as a way of classifying living organisms...
lineages are present and adapting to their present-day ecological niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
s.
By the distribution of fossils, the Paleogene radiation seems to have originated in Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, which at that time became a highly fragmented landscape as the Himalayas
Himalayas
The Himalaya Range or Himalaya Mountains Sanskrit: Devanagari: हिमालय, literally "abode of snow"), usually called the Himalayas or Himalaya for short, is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau...
lifted up and the Turgai Strait started to disappear.
The Cypselomorphae are part of the proposed Metaves. The material evidence for this group is very equivocal; the most ancient Cypselomorphae are quite nondescript tree-dwellers but already tend towards peculiarly apomorphic feet, and no Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
fossils are known that would link them to other "Metaves" such as Mirandornithes
Mirandornithes
Mirandornithes is a clade that consists of flamingos and grebes. The relationships of both groups have been problematic. Flamingos had been placed with numerous branches within Neognathae, such as ducks and storks. The grebes had been placed with the loons. However recent studies seem to confirm...
.
Torpor
Torpor
Torpor, sometimes called temporary hibernation is a state of decreased physiological activity in an animal, usually characterized by a reduced body temperature and rate of metabolism. Animals that go through torpor include birds and some mammals such as mice and bats...
and other metabolic peculiarities are very frequently found in this group, perhaps more often than in any other bird lineage.
Their shared apomorphies are: ossa maxillaria separated by a large cleft, a mandible with very short pars symphysialis, and rami mandibulae very slender in their distal half.