Maiaspondylus
Encyclopedia
Maiaspondylus is an extinct genus
of ophthalmosaurid ichthyosaur
known from Northwest Territories
of Canada
.
UALVP
45635, a disarticulated but nearly complete skeleton
preserved in three dimensions and from the referred materials UALVP 45639, two articulate
d partially preserved embryos and eight articulated vertebrae of an adult, UALVP 45640, 14 articulated vertebrae of a juvenile, UALVP 45640, 12 articulated vertebrae, UALVP 45642, a partial snout and left dentaries with teeth and UALVP 45643, a fragmentary snout. All specimens were collected at Hay River
from the Loon River Formation, dating to the early Albian
stage of the Early Cretaceous
, about 110 million years ago.
All Maiaspondylus specimens were originally referred to Platypterygius
. However, all recent cladistic analyses found that Maiaspondylus is a valid genus of ophthalmosaurid. Patrick S. Druckenmiller and Erin E. Maxwell (2010) found it to be most closely related to "Platypterygius
" americanus, which probably don't belong to the genus Platypterygius.
and the type species
is Maiaspondylus lindoei. The generic name is derived from maia (μαία), Greek
for "caring mother" and spondylos (σπόνδυλος), Greek for "vertebra". The generic name named in reference to the unique specimen, UALVP 45639, that composed of two embryos agglutinated to eight articulated vertebrae of an adult (within its body cavity), presumably the mother. Maxwell and Caldwell (2003) suggested that this specimen proves that Maiaspondylus was viviparous
, giving live birth. These embryos are the geologically youngest and the physically smallest known ichthyosaur embryos. The specific name honors the Geology Museum of the University of Alberta technician Allan Lindoe for discovering, collecting and preparating the specimens.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of ophthalmosaurid ichthyosaur
Ichthyosaur
Ichthyosaurs were giant marine reptiles that resembled fish and dolphins...
known from Northwest Territories
Northwest Territories
The Northwest Territories is a federal territory of Canada.Located in northern Canada, the territory borders Canada's two other territories, Yukon to the west and Nunavut to the east, and three provinces: British Columbia to the southwest, and Alberta and Saskatchewan to the south...
of Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
.
Description
Maiaspondylus is known from the holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
UALVP
University of Alberta
The University of Alberta is a public research university located in Edmonton, Alberta, Canada. Founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta and Henry Marshall Tory, its first president, it is widely recognized as one of the best universities in Canada...
45635, a disarticulated but nearly complete skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
preserved in three dimensions and from the referred materials UALVP 45639, two articulate
Articulate
Articulate may refer to:*Articulate *Articulate sign*Articulate sound*Joint, also known as articulation*Word modified by an article...
d partially preserved embryos and eight articulated vertebrae of an adult, UALVP 45640, 14 articulated vertebrae of a juvenile, UALVP 45640, 12 articulated vertebrae, UALVP 45642, a partial snout and left dentaries with teeth and UALVP 45643, a fragmentary snout. All specimens were collected at Hay River
Hay River
-Rivers:* Hay River * Hay River , a river in Alberta and Northwest Territories, Canada* Hay River , a river in south-western Australia...
from the Loon River Formation, dating to the early Albian
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma...
stage of the Early Cretaceous
Early Cretaceous
The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
, about 110 million years ago.
All Maiaspondylus specimens were originally referred to Platypterygius
Platypterygius
Platypterygius was an ichthyosaur of the family Ophthalmosauridae. It is most closely related to the genera Caypullisaurus and Brachypterygius.-Discovery and species:...
. However, all recent cladistic analyses found that Maiaspondylus is a valid genus of ophthalmosaurid. Patrick S. Druckenmiller and Erin E. Maxwell (2010) found it to be most closely related to "Platypterygius
Platypterygius
Platypterygius was an ichthyosaur of the family Ophthalmosauridae. It is most closely related to the genera Caypullisaurus and Brachypterygius.-Discovery and species:...
" americanus, which probably don't belong to the genus Platypterygius.
Etymology
Maiaspondylus was named by Erin E. Maxwell and Michael W. Caldwell in 20062006 in paleontology
-Insects:-Tetrapodomorphs:-Newly named temnospondylians:-Newly named amphibians:-Ichthyosaurs:-Newly named basal lepidosauromorphs:-Newly named plesiosaurs:-Newly named squamates:-Newly named crurotarsans:-Newly named dinosaurs:...
and the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is Maiaspondylus lindoei. The generic name is derived from maia (μαία), Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
for "caring mother" and spondylos (σπόνδυλος), Greek for "vertebra". The generic name named in reference to the unique specimen, UALVP 45639, that composed of two embryos agglutinated to eight articulated vertebrae of an adult (within its body cavity), presumably the mother. Maxwell and Caldwell (2003) suggested that this specimen proves that Maiaspondylus was viviparous
Vivipary
Vivipary has two different meanings. In animals, it means development of the embryo inside the body of the mother, eventually leading to live birth, as opposed to laying eggs...
, giving live birth. These embryos are the geologically youngest and the physically smallest known ichthyosaur embryos. The specific name honors the Geology Museum of the University of Alberta technician Allan Lindoe for discovering, collecting and preparating the specimens.