Bull. nat. Hist. Mus. Lond. (Geol.) 53(2): 135-138 
Issued 27 November 1997 
New information on Cretaceous crabs 
C.W. WRIGHT 
The Old Rectory, Seaborough, Beaminster, Dorset DT8 3QY 
SYNOPSIS. 
Re-examination of the supposedly Jurassic, Tithonian crab fauna from Klement in Austria shows that it is 
Cretaceous, Cenomanian, thus removing the puzzling record of Diaulax from the Jurassic. A new species of Paranecrocarcinus 
is described from the Lower Cretaceous, Barremian of Zululand, South Africa. New material from the English Lower Cretaceous 
is described, including a new species of Rathbunopon from the Lower Aptian and important new information about Withersella. 
THE KLEMENT ‘TITHONIAN’ CRAB FAUNA 
In 1931 Glaessner listed a small fauna of Crustacea from a block of 
presumed Tithonian limestone in a conglomerate at Klement in 
Lower Austria. It is of importance because it included a species of 
Diaulax, a relatively advanced genus otherwise known only from the 
Cretaceous, Lower Albian to Cenomanian. Shortly before his death 
Glaessner entrusted me with his Klement specimens with a view to 
joint description, since he had doubts about their Jurassic date. 
These doubts were fully justified, since revised identifications indi- 
cate that the fauna is almost certainly of Cenomanian date. 
The original (Glaessner, 1931) and the new identifications are: 
Original: Revised: 
Prosopon verrucosum Reuss Rathbunopon obesum (Van 
Straelen) 
Pithonoton marginatum Meyer Pithonoton cenomanense 
Wright & Collins 
Cyphonotus oxythyreiformis 
(Gemmellaro) 
Diaulax sp. 
Palaeodromites incertus (Bell) 
Diaulax oweni (Bell) 
The *Prosopon verrucosun’ (BMNH IC 6, Fig. 1) resembles very 
closely the fragmentary English Cenomanian specimen identified 
by Wright & Collins (1972: 23, pl. 1, fig. 8) as Rathbunopon obesum 
(Van Straelen), a species originally described from the Cenomanian 
of Navarre, Spain. A second, minute, specimen (BMNH IC 14, Fig. 
2) probably belongs to the same species but is too juvenile for certain 
attribution. 
The ‘Pithonoton marginatun’ (BMNH IC 17, Fig. 3) conforms 
well with P. cenomanense Wright & Collins in the outline of the 
cephalothorax, the course of the cervical and branchiocardiac 
grooves, and the disposition of the granules. Differences between 
species of Pithonoton are generally fine, but identity with P 
cenomanense seems highly probable. 
The ‘Cyphonotus oxythyreiformis’ (BMNH IC 8, Fig. 4), though 
incomplete, is beautifully preserved and is undoubtedly identical 
with Palaeodromites incertus, of which an English specimen of the 
same size is figured for comparison (Fig. 5). Species of 
Palaeodromites were shown by Wright & Collins to have a short 
range in the Cretaceous and this Klement specimen alone is suffi- 
cient to demonstrate the Cenomanian age of the fauna. 
The ‘Diaulax sp.’ (BMNH IC 7, Fig. 6) is certainly a Diaulax and 
differs in no way from the abundant English material of D. oweni 
from the Lower Albian to the Cenomanian. The immediate ancestor 
of D. oweni has not been identified but Wright & Collins (1972: 55) 
referred to the origin of Diaulax in “broad flat species of Pithonoton’ ; 
© The Natural History Museum, 1997 
they commented (p. 56) on the supposed Upper Jurassic occurrence 
from Klement as representing ‘a very early development of a 
relatively advanced carapace form’, an anomaly now removed by 
the revised dating of the Klement fauna. 
A NEW SPECIES OF PARANECROCARCINUS 
FROM THE BARREMIAN OF ZULULAND 
Genus Paranecrocarcinus Van Straelen, 1936 
TYPE SPECIES. Paranecrocarcinus hexagonalis Van Straelen, 1936 
(p. 36, pl. 4, figs. 6, 7) from the Hauterivian of Auxerre, France, by 
monotypy. 
DISCUSSION. Wright & Collins (1972) differentiated 
Paranecrocarcinus from Necrocarcinus by the bifid rostrum of the 
former and the trifid rostrum of the latter. They then united Forster’s 
(1968) Protocarcinus, as a synonym, and Pseudonecrocarcinus as a 
subgenus of Paranecrocarcinus, separating the two subgenera partly 
on the basis that P (Paranecrocarcinus) did not have and P. 
(Pseudonecrocarcinus) did have post-rostral slits in the carapace. 
This distinction was false, since the type species P. hexagonalis does 
have post-rostral slits. The remaining diagnostic character of 
Pseudonecrocarcinus, the many small rounded tubercles on the 
surface of the carapace, as seen both in the Maastrichtian type 
species P. (Pseudonecrocarcinus) quadriscissus (Noetling) and in 
the Cenomanian P. (P) biscissus Wright & Collins, might be thought 
sufficient to justify the two subgenera. However, some doubt is cast 
on this idea by the juvenile specimen of P. biscissus discussed in the 
last section of this paper below. Provisionally I am inclined to 
abandon the distinction of two subgenera. 
Paranecrocarcinus kennedyi sp. nov. Figs 7, 13 
NAME. For Professor W J Kennedy who found the specimen. 
HOLOTYPE. BMNH IC 16, from the Barremian Makatini Forma- 
tion, Mlambongwenya Spruit, Zululand, South Africa. 
DIAGNOsIS. A Paranecrocarcinus with a transverse row of nine 
tubercles across the gastric regions and a single one on each 
metabranchial lobe and with two prominent spines on the anterola- 
teral border; apparently without post-rostral slits. 
DESCRIPTION. The holotype consists of an internal mould with the 
rostrum and margins only partially preserved, together with the 
counterpart showing the central area of the cephalothorax in hard 
