Pyritocephalus sculptus ( FRIČ , 1875)

Štamberg, Stanislav, 2013, Knowledge Of The Carboniferous And Permian Actinopterygian Fishes Of The Bohemian Massif - 100 Years After Antonín Frič, Acta Musei Nationalis Pragae Series B 69 (3 - 4), pp. 159-182 : 176

Pyritocephalus sculptus ( FRIČ, 1875)

Text-fig. 2 , fig. 6

1875 1894 1944 1978

1991 Palaeoniscus sculptus FR. ; Frič, p. 73

Pyritocephalus sculptus, FR. ; Fritsch, p. 86; fig. 280; pl. 115. Pyritocephalus sculptus FRIČ ; Westoll, p. 43; figs 23–27.

Pyritocephalus sculptus FRIČ, 1895 ; Štamberg, p. 276; figs 1–6; pls. 60–63.

Pyritocephalus sculptus (FRIČ, 1883) ; Štamberg, p. 97; fig. 53; pl. 24.

L e c t o t y p e ( Štamberg 1978): Specimen figured by Fritsch (1894) on pl. 115, fig. 4, deposited in the National Museum, Prague under No. M 1201.

D i a g n o s i s (after Štamberg 1991, emended): Slender fish not exceeding 70 mm. Pectoral fins consist of 10–15 lepidotrichia, pelvic fin small with short base consists of 6–9 lepidotrichia. Dorsal and anal fins approximately of the same size, dorsal fin consists of 7–9 lepidotrichia, anal fin of 8–12 lepidotrichia. All lepidotrichia segmented, distally only, exceptionally bifurcated near the distal tip, and distally separated from each other. Caudal fin not deeply cleft. Rostral part of the head not conspicuously convex, composed of paired rostro-premaxillar and nasal, unpaired postrostral, and sometimes the second small postrostral is developed orally. The paired dermal bones of the skull roof (parietal, frontal, dermopterotic) coalesce into one unit, often without visible sutures, and constitute a characteristic: formation with a large paired fenestration on the lateral sides. The fenestration is usually circular, but it can be also anteroposteriorly elongated. From two to four suborbitals are located in front of the preoperculum. Very large orbit is surrounded by dermosphenotic, nasal, rostro-premaxillar and narrow infraorbital bones. Maxilla with well-developed maxillary plate, the length/height ratio of the maxillary plate is 1.2. Lower jaw strong. Teeth on the jaws are not developed. The preoperculum not oblique, it inclines orally at angle 65°. Small triangular antoperculum present. Operculum inclines 67° anteriorly, and is dorsoventrally elongated, 2.5 times higher than the small triangular suboperculum. Branchiostegal rays are not developed, series of one median and two pairs of gulars between jaws is present. The scales are smooth, not pectinated on their posterior margin. The scale count

21–24

25–28

6–8 14–17 23–25

T y p e l o c a l i t y: Nýřany , district Plzeň, Czech Republic .

S t r a t u m t y p i c u m: Nýřany Member, Westphalian D, Late Carboniferous, Plzeň Basin.

O c c u r r e n c e: Nýřany, Třemošná.

R e m a r k s: Species Pyritocephalus sculptus described and figured initially by Fritsch (1894) was redescribed and excellently revised by Westoll (1944). Westoll (1944) placed four more species from the Late Carboniferous into the genus Pyritocephalus , namely P. lineatus (Newberry, 1856) from Linton (Ohio, USA), P. gracilis (Newberry and Worthen, 1870) and P. comptus Westoll, 1944 from Mazon Creek (Illinois, USA) and P. rudis Westoll, 1944 from Newsham (Northumberland, England). Huber (1992) later assigned to the genus P. lowneyae Huber, 1992 a specimen from the Pennsylvanian of Kinney Brick Quarry (New Mexico, USA). The above-mentioned species are alike in the anatomy of the head, structure of the fins, shape of the scales and their body. Westoll (1944) considered the species characters mainly in the formation of coalesced bones of the skull roof and in the variation of the scale count. Study of the numerous collections of P. sculptus from the National Museum, Prague and from the Museum of Western Bohemia in Plzeň demonstrated ( Štamberg 1978) considerable variability in the shape of coalesced bones of the skull roof, in the shape of the fenestration on the lateral side of the skull roof and variation in the scale count. For that reason, Štamberg (1978) did not find differences among P. sculptus from the Plzeň Basin, P. gracilis from Mazon Creek and P. lineatus from Linton.

Figures

Text-fig. 2. Reconstruction of some Westphalian and Stephanian actinopterygians. Figs 1 – 5 after Štamberg (1991), Fig. 6 after Westoll (1944). Scale bars represent 20 mm. 1 – Acrolepis gigas (FRIČ, 1877), 2 – “Elonichthys” krejcii (FRITSCH, 1895), figured after the original holotype of Acrolepis sphaerosideritarum FRITSCH, 1895, 3 – “Elonichthys” krejcii (FRITSCH, 1895), figured after the original holotype of Acrolepis krejcii FRITSCH, 1895, 4 – Sphaerolepis kounoviensis FRIČ, 1877, 5 – Sceletophorus biserialis FRITSCH, 1894, 6 – Pyritocephalus sculptus (FRIČ, 1875).