0000000000132892
AUTHOR
Elga Mark-kurik
The earliest evidence of host-parasite interactions in vertebrates
Luk s evics, E., Lebedev, O. A., Mark-Kurik, E. and Karataj u te-Talimaa, V. 2009. The earliest evidence of host‐parasite interactions in vertebrates. — Acta Zoologica (Stockholm) 90 (Suppl. 1): 335‐343 Traces of parasite action have been discovered in the Middle‐Upper Devonian fish from Estonia, Latvia and European Russia. Such traces are known in heterostracan Psammolepis venyukovi , antiarchs Asterolepis radiata and Bothriolepis ciecere , sarcopterygians Holoptychius sp., Ventalepis ketleriensis and Eusthenodon sp. nov. The traces include evidence of parasitic fixation and penetration as well as dwelling traces. Pathologies are developed as (1) round fossulae on the external surface of b…
On the tail ofErrivaspisand the condition of the caudal fin in heterostracans
Articulated caudal fins of heterostracans are preserved in very rare cases. Their morphology and internal structure are completely unknown for the majority of species. One of the few preserved caudal fins belongs to the Early Devonian pteraspidid Errivaspis waynensis from the Welsh Borderland, UK. There are two different reconstructions of the tail: (1) strongly asymmetric, with a considerably longer ventral lobe, and a rather concave posterior margin (e.g. White 1935); and (2) almost symmetrical with an only slightly longer ventral lobe and a small notch in the posterior margin (e.g. Blieck 1984). A new reconstruction of the Errivaspis caudal fin, based on a detailed study of White's speci…
A near-tetrapod from the Baltic Middle Devonian
The tetrapodomorph sarcopterygian Livoniana multidentata gen. et sp. nov. is described on the basis of lower jaw fragments from the Middle Devonian(late Givetian) of Latvia and Estonia. It possesses a suite of derived characters previously only known from tetrapods, which first appear in the late Devonian (late Frasnian), and a phylogenetic analysis places it on the internode between Panderichthys and the base of the Tetrapoda. The analysis also reveals that the ‘Elpistostegalia’ are paraphyletic to Tetrapoda, with Elpistostege closer to tetrapods than is Panderichthys. Owing to incompleteness of the material, there is almost no overlap between the data sets for ElpistostegeLivoniana; the a…
Bite marks as evidence of predation in early vertebrates
Study of lifetime bite traces on agnathans and fish (or gnathostomes) from Ukraine, Estonia, Latvia and north-western and central European Russia reveals evidence of predator–prey relationships in communities of Devonian age. Numerous bite traces on skeletal parts of agnathan pteraspidiforms and psammosteiforms, placoderm arthrodires and antiarchs and sarcopterygian porolepiforms and osteolepiforms are described. Evidence of healing shows that prey organisms responded to predation by reconstruction of damaged skeletal elements. Ichthyofaunistic analysis is used to establish possible predators. The most probable predators in the Middle and Late Devonian communities are sarcopterygian porolep…
A long-snouted late Eifelian arthrodire from Aragon (Spain)
Carolowilhelmina geognostica Carls, 1995 is a large arthrodire (Placodermi) from the Tortodus kockelianus Conodont Zone, late Eifelian, in the Eastern Iberian Cordillera in southern Aragon. The somewhat incomplete but articulated skull is preserved, showing a long tubular rostral plate, very small postnasal plates, low toothless inferognathals, and a small, slender and flat parasphenoid. Supraorbital and central sensory lines meet their antimeres at the midline of the skull, forming a straight double line. Lines along the ventral surface of the rostral plate probably belong to the suborbital branches of the infraorbital sensory lines. The combination of characters of Carolowilhelmina points…