| Kujdanowiaspis Temporal range: Early Devonian, | |
|---|---|
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| Artist's reconstruction of K. buczacziensis | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | † Placodermi |
| Order: | † Arthrodira |
| Genus: | † Kudjanowiaspis Stensiö, 1942 |
| Species | |
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Kujdanowiaspis is an extinct genus of arthrodire placoderm fish from the Early Devonian of Podolia (Ukraine), Poland and Spain. [1] [2] [3] Kujdanowiaspis is known from many fragmentary head shields and body armours. [4]
Kujdanowiaspis consists of three species, all described in 1934: Kujdanowiaspis buczacziensis (type species), Kujdanowiapsis podolica, and Kudjanowiaspis rectiformis - although the independent status of K. rectiformis is in doubt, and is instead most likely K. podolica. [4] [5] [6] Kujdanowiaspis zychi was also named and described by Stensiö in 1945, but was reassigned to the new genus Erikaspis in 2007. [4] [5]
Kujdanowiaspis is one of the more basal members of the order Arthrodira, as shown in the cladogram below: [7]
| Actinolepidoidei Phlyctaeniina |
Because of the poor preservation of Kujdanowiaspis fossils, little is known about its physiology. What is known about it is typical of actinolepid placoderms, and it can compared to the better known primitive arthrodires such as Dicksonosteus or Actinolepis . It had a very pronounced, serrated spinal plate, giving it an almost lunate dorsal silhouette. [4]
The body of Kujdanowiaspis is slightly wider than high, with large spinal plates protruding laterally, suggesting a benthic lifestyle. The body armour of the genus Erikaspis is much flatter. [5]
Its jaws were comparatively underdeveloped in comparison to the more robust-jawed arthrodires that would come after it, such as Dunkleosteus and Coccosteus , indicating that it likely subsisted primarily on smaller, softer-bodied animals such as mollusks or worms instead of larger, tougher prey animals.
Placodermi is a class of armoured prehistoric fish, known from fossils, which lived from the Silurian to the end of the Devonian period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked, depending on the species. Placoderms were among the first jawed fish; their jaws likely evolved from the first of their gill arches.
Arthrodira is an order of extinct armored, jawed fishes of the class Placodermi that flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetrating most marine ecological niches. Arthrodires were the largest and most diverse of all groups of placoderms.
Arctolepis is an extinct genus of placoderm arthrodire fish which lived during the Early Devonian period. Fossils of Arctolepis have been found in what is now Norway and Michigan.
Dicksonosteus is an extinct genus of basal arthrodire placoderm fish which lived during the Early Devonian period of Spitsbergen, Norway.
Pageauaspis is an extinct placoderm fish, which lived during the Devonian period of North America.
Heintzosteus is an extinct genus of placoderm arthrodire fish, which lived during the Late Devonian period in Spitsbergen, Norway.
The Xitun Formation is a palaeontological formation which is named after Xitun village in Qujing, a location in South China. This formation includes many remains of fossilized fish and plants of the Early Devonian period. It was originally referred to as the Xitun Member of the Cuifengshan Formation.
Actinolepidae is an extinct family of placoderm fishes which lived during the Early Devonian period. They are considered to be among the most primitive of the arthrodires, and are widely accepted to be phylogenetically basal to the group.
Aleosteus is an extinct monospecific genus of arthrodire placoderm fish of the Early Devonian period. The type species Aleosteus eganensis was described in 2000, and was found in the Late Emsian strate of the Sevy Dolomite Formation, in the Egan Range of east-central Nevada, USA. Almost complete fossils belong to juvenile and adult specimens and show a short and broad skull, posteriorly concave.
Wuttagoonaspidae is a family of extinct primitive arthrodire placoderm fishes from Early Devonian China and Middle Devonian Australia. It contains two genera, Wuttagoonaspis and Yiminaspis, some of the more basal members of the order Arthrodira, as shown in the cladogram below:
Wuttagoonaspis is a extinct genus of primitive arthrodire placoderm fish from the Middle Devonian of Australia. The box-like skull is up to 18 centimeters in length, and the median dorsal plate averages in length about 10 centimeters. It contains two species: the type species Wuttagoonaspis fletcheri, described by Ritchie in 1973, and Wuttagoonaspis milligani, described by Young and Goujet in 2003.
Yiminaspis is an extinct monospecific genus of primitive arthrodire placoderm fish from Emsian-aged marine strata in Yunnan, China. The type species Yiminaspis shenme was named and described in 2008, and is known from a flattened partial skull and portions of the thoracic armor.
Romundina is a small, heavily armored extinct genus of acanthothoracid placoderms which lived in shallow marine environments in the early Devonian (Lochkovian). The name Romundina honors Canadian geologist and paleontologist Dr. Rómundur (Raymond) Thorsteinsson of Calgary, Alberta, Canada. Romundina are believed to have lived on Earth between 400 and 419 million years ago. The closest known relative to Romundina is the acanthothoracid Radotina. The type and only described species is R. stellina.
Yujiangolepis is an extinct monospecific genus of arthrodire placoderm fish from the Pragian stage of the Devonian period. The type species is Yujiangolepis liujingensis, described from a single incomplete skull roof from the Nakaoling (Nagaoling) Formation of Hengxian, Guangxi, South China. It is one of the more basal members of the order Arthrodira, closely related to Antarctaspis, as shown in the cladogram below:
Antarctaspis is an extinct monospecific genus of arthrodire placoderm fish which existed in Antarctica during the Devonian period. The type species Antarctaspis mcmurdoensis was described White in 1968, and is known from a partial head shield discovered in the Lashly Mountains of Antarctica. It is one of the more basal members of the order Arthrodira, closely related to Yujiangolepis, as shown in the cladogram below:
Aethaspis is an extinct genus of arthrodire placoderm fish from the Devonian period. Two species were described by Denison in 1958: Aethapsis major and Aethapsis utahensis. It is one of the more basal members of the order Arthrodira, as shown in the cladogram below:
Lehmanosteus is an extinct monospecific genus of arthrodire placoderm fish, named after French paleontologist Jean-Pierre Lehman. The type species Lehmanosteus hyperboreus was described in 1984, and was found in Early Devonian strata of the Wood Bay Formation on the island of Spitsbergen, Svalbard in Norway.
Simblaspis is an extinct monospecific genus of arthrodire placoderm fish of the Early Devonian period. The type species Aleosteus eganensis was described in 1958, and was found in Pragian strata of the Qasr Limestone in Saudi Arabia.
Heightingtonaspis is an extinct genus of primitive arthrodire placoderm from Canada, England and Wales with two species previously allied with the genus Kujdanowiaspis.
