Paramblypterus, SAUVAGE, 1888

Štamberg, Stanislav, 2021, Actinopterygians Of The Broumov Formation (Permian) In The Czech Part Of The Intra-Sudetic Basin (The Czech Republic), Fossil Imprint 77 (1), pp. 73-101 : 84-86

Paramblypterus zeidleri ( FRITSCH, 1895)

Text-fig. 8a

1895 Amblypterus Zeidleri, FR. ; Fritsch, p. 113, pl. 125, figs 4–5. 2008 Paramblypterus zeidleri ( FRITSCH, 1895); Štamberg and

Zajíc, p. 159, fig. 239.

L e c t o t y p e. Designated here. Specimen NM-M 901 described and figured by Fritsch (1895: pl. 125, figs 4–5 and Text-fig. 8a herein).

T y p e l o c a l i t y. Ruprechtice, Intra-Sudetic Basin, the Czech Republic.

S t r a t i g r a p h i c h o r i z o n a n d a g e o f t h e t y p e l o c a l i t y. Ruprechtice Limestone Horizon, Olivětín Member, Broumov Formation, Asselian, lower Permian.

O c c u r r e n c e. Ruprechtice, (Olivětín Member, IntraSudetic Basin).

R e m a r k s. Fritsch (1895) designated Amblypterus zeidleri on the basis of specimen NM-M 901 which comes from the limestone of the Ruprechtice Horizon of the IntraSudetic Basin, and this author ( Fritsch 1895: 113; housed in the National Museum , Prague) assigned to the same species another very deformed specimen from the Kalná Horizon of the Prosečné Formation ( Krkonoše-Piedmont Basin ). The following description is based only on the lectotype NM-M 901 as no other specimen from the Ruprechtice and Otovice horizons corresponds to the characters of the lectotype .

D i a g n o s i s. Body fusiform reaches a total length 16 cm. Total body length is 4.1 times that of the deepest part of the body. The dorsal fin begins behind the mid point of the total body length. The scales between the skull and pelvic fin bear fine diagonally arranged ridges terminating in denticulation posteriorly.

Description of the type specimen NM-M 901. A fish of fusiform shape which may reaches a total length of 160 mm. The total body length is 4.1 times that of the deepest part of the body and 5.6 times the length of the skull. The bones of the skull roof are indistinct and only partial contours of the maxilla, lower jaw, operculum and suboperculum, supracleithrum and posttemporal are visible. The maxilla has a deep quadrangular postorbital maxillary plate. The coronoids in the anterior part of the lower jaw bear numerous short teeth. The operculum is of oblong shape, slightly elongated dorsoventrally. The suboperculum is the same length as the operculum, but its depth is only 50 % the depth of the operculum. The dorsoventrally elongated supracleithrum has a ventral margin which extends to the upper third of the suboperculum depth. The supracleithrum is in contact with the posttemporal dorsally.

A fragment of the pelvic fin is situated closer to the anal fin than to the skull. The base of the dorsal fin extends over a length of 7 scale rows, and a field of minute scales occurs along the fin base. This fin begins beyond the midpoint of the total body length, and the base of the dorsal fin is perpendicular to the base of the anal fin. The dorsal fin has a triangular shape which consists of 28–30 segmented lepidotrichia. The base of the anal fin extends over a length of 9 scale rows, it consists of approximately 30 segmented lepidotrichia, and similarly as in the dorsal fin, a field of small scales occurs along the fin base. Segments of the lepidotrichia in all fins are short and solid. The heterocercal caudal fin has a dorsal lobe which significantly exceeds the length of the incompletely preserved ventral lobe.

The scales covering the trunk are preserved as imprint. The scales behind the skull, similarly as in P. vratislaviensis, bear fine ridges passing diagonally across the outer surface of the scale and terminating as small denticles on the posterior edge of the scales. Fine ridges have been recorded on the scales below the lateral sensory canal in the region between the skull and pelvic fin. Fine ridges and number of denticles on scales decrease in a posterior direction, and after the 10 th scale row they are completely absent. The scales are not completely smooth, as described by Fritsch (1895), but have similar sculpture as Paramblypterus vratislaviensis. The scale count is:

29 ––––––––––––––––– 42 10 23 39

Four large ridge scales precede the base of the dorsal fin. Large scutes cover the dorsal edge of the caudal peduncle and large anteroposteriorly elongated basal fulcra continue on the dorsal edge of the dorsal lobe of the caudal fin. Two large scutes precede the basal fulcra of the ventral lobe of the caudal fin. The 23 rd row of scales in front of the anal fin contains 11 scales below the lateral sensory line and 12 scales above the lateral sensory line. The inclination of the above mentioned row of scales to the horizontal plane is 70°. It is 5°–10° greater than in well preserved specimens of Paramblypterus vratislaviensis or Paramblypterus cf. rohani. It is possible that under an ideal state of conservation, the base of the dorsal fin would be moved more anteriorly.

Figures

Text-fig. 8. a: Paramblypterus zeidleri (FRITSCH, 1895), Lectotype NM-M 901 from the locality Ruprechtice, scale bar 10 mm; b: Paramblypterus cf. rohani, significantly deformed specimen from the locality Otovice “Stěnava”, DP 4529, scale bar 10 mm; c: Paramblypterus cf. rohani, significantly deformed specimen from the locality Otovice “Stěnava”, DP 4257, scale bar 10 mm.