Post by theropod on Jul 25, 2014 21:04:34 GMT 5
Kulindadromeus zabaikalicus is a small (~1.5m TL) neoornithischian dinosaur from the lower Ukureyskaya Formation.
Specimens of this taxon have been collected at the Kulinda locality in southeastern Siberia close to the border to China and Mongolia between 2010 and 2013, not all the material is prepared and studied yet.
Holotype: INREC K3/109, partial cranium, probably a subadult or juvenile
Referred: several hundred disarticulated specimens (two bonebeds) including six incomplete skulls, mostly small (supposedly young) individuals and few adults.
Diagnosis: "Maxilla with rostral ascending process much lower than caudal ascending process and
maxillary fenestra larger than antorbital fenestra; jugal with notched postorbital ramus;
postorbital with dorsoventrally expanded caudal ramus; dorsoventrally slender postacetabular
process on ilium; deep extensor fossae on metatarsals II-IV." (from Godefroit et al. 2014)
Phylogeny:
K. zabaikalicus was recovered as a Neoornithischian more basal than Cerapoda by its describers, based on a phylogenetic analysis that included 48 taxa and 227 characters. K. zabaikalicus was not recovered as a member of Cerapoda because it, like Agilisaurus louderbacki and Hexinlusaurus multidens lacks three of the synapomorphies that are present within the clade. However, it has been considered to be closer to Cerapoda than the two mentioned taxa (Godefroit et al. 2014, Fig.S10). The phylogenetic position is weakly supported, since the bootstrap value of the Cerapoda + Kulindadromeus clade are weak (= lower than 50).
Osteology:
The skull is triangular and brevirostrine in shape, resembling Jeholosaurus, with the rostrum less than 50% of the whole skull lenght. The relatively wide nasals and long frontals make the roof of the snout relatively broad and the skull roof large as a whole.
The infratemporal fenestra is short and tall, the supratemporal fenestra is longer than wide. By comparison with the orbit, antorbital fossa and maxillary fenestra, than antorbital fenestra is small. The quadrate is short rostrocaudally and deep dorsoventrally, the head articulating with the squamosal being bent backwards and located posterior to the mandibular articulation.
The mandible is relatively elongated and shallow, the surangular does not bear a fenestra, unlike in basal ornithopods.
Tooth count is at least 3 for the premaxilla, 19+ for the maxilla and more than 17 for the dentary. The anterior teeth are slightly recurved and unserrated, while those of the dentary (and likely maxilla) are mesiodistally long, low-crowned and display coarse serrations (picture of the teeth from archosaur musings→).
The postcranial axial skeleton of Kulindadromeus is only known in part. INREC K4/159 preserves 11 articulated distal caudals, INREC K4/150 four proximal ones. The central become increasingly elongated (lenght/height=>2) posteriorly, and bear strongly elongated zygapophyses and absent or very low neural arches.
The scapular blade is relatively narrow and has a straight anterior edge. The medially bent humerus is longer than the scapula and has a deltopectoral crest with a prominent lateral expansion. The ulna is curved so that a relatively large space between it and the radius may have been present, which might have allowed some pronation of the manus.
Kulindadromeus has long, slender ilium and pubis with caudally curving posterior processes and a subcircular acetabulum. The femoral head extends above the greater trochanter due to the long neck which is at an obtuse angle to the shaft. The femoral shaft is slender and curved caudally, with a seemingly particularly robust fourth trochanter on the proximal part, the distal condyles are indistinct. The tibia and fibula are particularly gracile, the former bearing a weakly developed cnemial crest. The metatarsals, bearing deep extensor fossae, appear to have been closely articulated in life.
Overall, its skeletal structure suggests an animal with a short skull, long and elongate hindlimbs and tail and relatively short forelimbs.
Integument:
Kulindadromeus is particularly notable for its diverse array of integumentary features. These include three types of filaments and three types of scales:
• The distal parts of the calves bore small (<3.5mm), imbricated scales resembling the scutella of extant avians
• The pes and manus bore even smaller (<1mm), separate scales resembling bird reticulae
• The dorsal side of the tail was covered by at least five rows of large, thin overlapping scales
• Large parts of its body were covered in monofilaments ranging in lenght from 1 to 3 centimetres and from 0.15 to 0.3mm in width, the smallest being found on the head and the larger ones covering the torso.
• The proximal limb parts are covered by complex structures consisting of multiple filaments that arise from a basal plate (Picture from archosaur musings→), which the authors consider similar to the body covering of some breeds of domestic chicken. These structures are larger (3-4mm wide basal plate) and thicker on the humerus than on the tigh (2-3mm wide basal plate).
The possibility of the integument representing collagen fibers was considered to be unlikely by the authors, on the basing of the spacing and size of the filaments. The preservation mode is identical to that of all other dinosaurs where filaments have been reported.
Palaeobiology:
Kulindadromeus was likely a small plant eater. It’s proportions and morphology hint at it being a fast runner that was predominantly (though not exclusively) bipedal. It may have shared its habitat with a fauna resembling that of the similarly-aged Tiaojishan Formation.
Note on citations: Where not noted otherwise, the source is Godefroit et al. 2014. Since pretty much everything in here is based onthat paper, it would be pointless to write that every single time.
References & Further reading:
• Godefroit et al. 2014: A Jurassic ornithischian dinosaur from Siberia with both feathers and scales (paper→ | supplement→)
• archosaurmusings.wordpress.com/2014/07/24/kulindadromeus-images/
• Hone 2014: Siberian dinosaur spreads feathers around the dinosaur tree (link→)
Specimens of this taxon have been collected at the Kulinda locality in southeastern Siberia close to the border to China and Mongolia between 2010 and 2013, not all the material is prepared and studied yet.
Holotype: INREC K3/109, partial cranium, probably a subadult or juvenile
Referred: several hundred disarticulated specimens (two bonebeds) including six incomplete skulls, mostly small (supposedly young) individuals and few adults.
Diagnosis: "Maxilla with rostral ascending process much lower than caudal ascending process and
maxillary fenestra larger than antorbital fenestra; jugal with notched postorbital ramus;
postorbital with dorsoventrally expanded caudal ramus; dorsoventrally slender postacetabular
process on ilium; deep extensor fossae on metatarsals II-IV." (from Godefroit et al. 2014)
Phylogeny:
K. zabaikalicus was recovered as a Neoornithischian more basal than Cerapoda by its describers, based on a phylogenetic analysis that included 48 taxa and 227 characters. K. zabaikalicus was not recovered as a member of Cerapoda because it, like Agilisaurus louderbacki and Hexinlusaurus multidens lacks three of the synapomorphies that are present within the clade. However, it has been considered to be closer to Cerapoda than the two mentioned taxa (Godefroit et al. 2014, Fig.S10). The phylogenetic position is weakly supported, since the bootstrap value of the Cerapoda + Kulindadromeus clade are weak (= lower than 50).
Osteology:
The skull is triangular and brevirostrine in shape, resembling Jeholosaurus, with the rostrum less than 50% of the whole skull lenght. The relatively wide nasals and long frontals make the roof of the snout relatively broad and the skull roof large as a whole.
The infratemporal fenestra is short and tall, the supratemporal fenestra is longer than wide. By comparison with the orbit, antorbital fossa and maxillary fenestra, than antorbital fenestra is small. The quadrate is short rostrocaudally and deep dorsoventrally, the head articulating with the squamosal being bent backwards and located posterior to the mandibular articulation.
The mandible is relatively elongated and shallow, the surangular does not bear a fenestra, unlike in basal ornithopods.
Tooth count is at least 3 for the premaxilla, 19+ for the maxilla and more than 17 for the dentary. The anterior teeth are slightly recurved and unserrated, while those of the dentary (and likely maxilla) are mesiodistally long, low-crowned and display coarse serrations (picture of the teeth from archosaur musings→).
The postcranial axial skeleton of Kulindadromeus is only known in part. INREC K4/159 preserves 11 articulated distal caudals, INREC K4/150 four proximal ones. The central become increasingly elongated (lenght/height=>2) posteriorly, and bear strongly elongated zygapophyses and absent or very low neural arches.
The scapular blade is relatively narrow and has a straight anterior edge. The medially bent humerus is longer than the scapula and has a deltopectoral crest with a prominent lateral expansion. The ulna is curved so that a relatively large space between it and the radius may have been present, which might have allowed some pronation of the manus.
Kulindadromeus has long, slender ilium and pubis with caudally curving posterior processes and a subcircular acetabulum. The femoral head extends above the greater trochanter due to the long neck which is at an obtuse angle to the shaft. The femoral shaft is slender and curved caudally, with a seemingly particularly robust fourth trochanter on the proximal part, the distal condyles are indistinct. The tibia and fibula are particularly gracile, the former bearing a weakly developed cnemial crest. The metatarsals, bearing deep extensor fossae, appear to have been closely articulated in life.
Overall, its skeletal structure suggests an animal with a short skull, long and elongate hindlimbs and tail and relatively short forelimbs.
Integument:
Kulindadromeus is particularly notable for its diverse array of integumentary features. These include three types of filaments and three types of scales:
• The distal parts of the calves bore small (<3.5mm), imbricated scales resembling the scutella of extant avians
• The pes and manus bore even smaller (<1mm), separate scales resembling bird reticulae
• The dorsal side of the tail was covered by at least five rows of large, thin overlapping scales
• Large parts of its body were covered in monofilaments ranging in lenght from 1 to 3 centimetres and from 0.15 to 0.3mm in width, the smallest being found on the head and the larger ones covering the torso.
• The proximal limb parts are covered by complex structures consisting of multiple filaments that arise from a basal plate (Picture from archosaur musings→), which the authors consider similar to the body covering of some breeds of domestic chicken. These structures are larger (3-4mm wide basal plate) and thicker on the humerus than on the tigh (2-3mm wide basal plate).
The possibility of the integument representing collagen fibers was considered to be unlikely by the authors, on the basing of the spacing and size of the filaments. The preservation mode is identical to that of all other dinosaurs where filaments have been reported.
Palaeobiology:
Kulindadromeus was likely a small plant eater. It’s proportions and morphology hint at it being a fast runner that was predominantly (though not exclusively) bipedal. It may have shared its habitat with a fauna resembling that of the similarly-aged Tiaojishan Formation.
Note on citations: Where not noted otherwise, the source is Godefroit et al. 2014. Since pretty much everything in here is based onthat paper, it would be pointless to write that every single time.
References & Further reading:
• Godefroit et al. 2014: A Jurassic ornithischian dinosaur from Siberia with both feathers and scales (paper→ | supplement→)
• archosaurmusings.wordpress.com/2014/07/24/kulindadromeus-images/
• Hone 2014: Siberian dinosaur spreads feathers around the dinosaur tree (link→)