68 UPPER CRETACEOUS TELEOSTS 
Pelargorhynchus dercetiformis von der Marck 
(Text-fig. 31) 
1858 Pelargorhynchus dercetiformis von der Marck : 243. 
1954 Pelargorhynchus dercetifoymis von der Marck ; Siegfried : 16, pl. 6, figs. 2-4. 
Siegfried lists earlier references. 
D1aGNosis (emended). Pelargorhynchus of standard length not exceeding 49 cm. 
Vertebral column with 70 vertebrae. Head equal to one-fifth of the standard length. 
Maximum height of the head equalling one-fifth of the total head length. Dorsal fin 
with 64 rays, anal fin with 13 rays. Lateral line scutes elongate and heart-shaped. 
Ho.totyre. The holotype appears to have been lost, but two additional specimens 
used by von der Marck (1858, 1863) are present in the Palaontologisches Institut der 
Westfalische Wilhelms-Universitat, Miinster, numbers 8488 and A1/3, both from the 
Upper Senonian of Sendenhorst. 
MATERIAL. The two specimens in Minster together with a third specimen of a 
distorted trunk region in Miinster. These three specimens are all that could be 
traced of the species. The following description is very incomplete due to the poor 
preservation of the material. 
DESCRIPTION. Neurocranium. The neurocranium is shown in dorsal view in 
Text-figure 31. The frontals extend back almost to the occipital border and are long, 
narrow bones which meet in the mid-line. The widest point of the skull-roof is 
between the sphenotics on a level with the hind end of the orbit. The frontals are 
densely ornamented with rows of tubercles raised on bony ridges. These ridges 
radiate in all directions from the centre of ossification above the rear end of the 
orbit. The sphenotic is visible on one side of the roof as a triangular region project- 
ing laterally from beneath the frontal. The frontals are greatly extended anteriorly 
and taper from in front of the orbits. The mesethmoid component of the skull is 
prominent and acutely pointed anteriorly, but more posteriorly is composed of two 
divergent laminae of bone flanking the anterior region of the frontals. In lateral 
view the orbit appears small, the majority of the skull length being preorbital. The 
parietals are small, transversely orientated strips of bone near to the occipital border 
and bounded anteriorly by the frontals. The supraoccipital is a small bone which 
contacts the frontals anteriorly and separates the parietals in the mid-line. A 
supraoccipital crest was not observed but preservation was poor in this region. 
Both parietals bear a dense ornamentation of tubercles but the dorsal surface of the 
supraoccipital is smooth. Behind the parietals and forming the occipital border of 
the roof, two small unornamented expanses of bone are visible, the epiotics. 
Postero-lateral to the frontals the pterotics border the skull-roof. The pterotics 
are elongate and relatively narrow although they do expand slightly in width 
posteriorly. The pterotic projects backwards beyond the level of the occipital 
border. Posteriorly a slight indentation of the pterotic is visible in the posterior 
border of the neurocranium just lateral to the epiotic and the parietal, and would 
seem to indicate the presence of a post-temporal fossa. The indentation may mark 
