Kujdanowiaspis sp.
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publication ID |
https://doi.org/ 10.4202/app.00395.2017 |
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persistent identifier |
https://treatment.plazi.org/id/566487BD-1674-FFBB-AA58-FB63FA0DF80A |
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treatment provided by |
Felipe |
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scientific name |
Kujdanowiaspis sp. |
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Fig. 3A, C, E, F View Fig .
Material.—MZ-VIII/Vp-340 ( Fig. 3A View Fig ), Muz PGI 1733.II.37
Fig. 3C View Fig ), partially preserved head-shields; MZ-VIII/Vp- 515 ( Fig. 3E View Fig ), Muz PGI 1733.II.390 ( Fig. 3F View Fig ), postorbital plates; Podłazie hill, Lower Devonian, Emsian.
Description.—Skull roof: The largest specimen (PGI 1733. II.37, Fig. 3C View Fig ) shows very few details because of its high degree of weathering. It corresponds to the right part of a partial head shield. The surface is flat and shows no signs of secondary deformation. It is posteriorly concave just posteriorly to the central sensory line groove. Suture lines are not visible apart from the boundary between postorbital and paranuchal plates where it is emphasised by the linear pattern of ornamentation on a short distance. A faint supraorbital sensory groove can be distinguished. The central sensory line groove is well marked; it is 22 mm long and meets the infraorbital sensory groove at an angle of 63°. MZ-VIII/Vp-340 ( Fig. 3A View Fig ) corresponds to the left central and postorbital plates, belonging to a much larger individual: the central sensory line is 50 mm long, and meets infraorbital sensory groove at an angle of 61°. The surface is slightly depressed just behind the central sensory line groove. Ornamentation consists in randomly distributed tubercles whose diametre does not exceed 1.5 mm.
Postorbital plates: The postorbital plates are as wide as long and their outline is polygonal. The smallest specimen (Muz PGI 1733.II.390, Fig. 3F View Fig ), which represents a right postorbital plate, is well preserved and ornamented with tubercles up to 1 mm in diametre arranged in circles. This allows to locate the radiation center, which is situated at the level of the trifurcation, between the central and the two rami of the infraorbital sensory line grooves. MZ-VIII/ Vp-515 ( Fig. 3E View Fig ) corresponds to a left postorbital plate, and tubercles appear more worn than on the previous one. It also has a bigger angle between the infraorbital and central sensory grooves which equals 58°. The plate seems to be anteroposterioly elongated but no natural margin is preserved.
On the postorbital plates the common pattern of sensory grooves does not allow a precise identification of these specimens. They differ from the Kujdanowiaspis sp. described by Dupret (2010) by a different angle between the infraorbital and central sensory grooves which varies from 58° to 60° on Polish specimens and is 48–53° on Podolian specimens. All plates have broken margins and it is therefore impossible to determine relationships with other plates. Based on Muz PGI 1733.II.390 ( Fig. 3F View Fig ), which shows tubercules arranged in circular rows with the radiation centre more or less in the geometric centre of the specimen, it seems that the plate has an isometric shape.
Remarks.—The features visible on both head-shields do not allow a precise taxonomical identification because of the paucity of diagnostic sutures lines. However, the pattern of both central and partial infraorbital sensory grooves, together with the ornamentation are reminiscent of the Kujdanowiaspis and especially Kujdanowiaspis podolica (Brotzen, 1934) illustrated by Dupret (2010: fig. 13C). Polish specimens are however bigger than those illustrated by Dupret (2010: figs. 12, 13): the central sensory canal of K. podolica in Dupret (2010: fig. 13D) is almost 20 mm long whereas in MZ-VIII/Vp-340 ( Fig. 3A View Fig ) it is 50 mm long. In size only, described specimens would correspond to the Pragian actinolepid Eukaia elongata Mark-Kurik, 2013 described by Mark-Kurik (2013), to Erikaspis zychi (Stensiö, 1945) (see Dupret et al. 2007) or the Pragian Kujdanowiaspis buczacziensis (Brotzen, 1934) (see Dupret 2010), although the latter bears very minute and dense tubercles.
The occurence of such radiating tubercles from the geometric/growth centre of the plate fits the general shape of the postorbital plate in Kujdanowiaspis ( Dupret 2010: fig. 12). Additionally, tubercles are more scattered than on Podolian specimens but are the same size as in K. podolica . Although precise measurement of the complete plates was not achievable, the preserved parts are sufficient to state that the studied material corresponds to bigger representatives than K. podolica . We thus attribute them to Kujdanowiaspis sp.
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