Records of the Western Australian Museum 18: 193-202 (1996). 
Plio-Pleistocene Peronella (Echinoidea: Clypeasteroida) 
from Western Australia 
Kenneth J. McNamara 
Department of Earth and Planetary Sciences, Western Australian Museum, Francis Street, 
Perth, Western Australia 6000, Australia 
Abstract - Three species of the laganid clypeasteroid Peronella are described 
from sediments of Pliocene and Pleistocene age in the Carnarvon, Perth and 
Eucla Basins in Western Australia. The oldest is Peronella ova sp. nov. from 
the Pliocene Roe Calcarenite of the Eucla Basin. Laganum decagonale rictum 
Gregory, 1892, is redescribed, elevated to specific status and placed in the 
genus Peronella. Peronella ricta appears to be restricted to the basal part of the 
Carbla Oolite, a Middle Pleistocene formation in the Carnarvon Basin 
outcropping around Shark Bay. Late Pleistocene sediments in the Shark Bay 
region contain the still extant species P. orbicularis. The living species P. 
lesueuri is recorded from Holocene sediments in the Perth Basin. A key to 
fossil Peronella in Western Australia permits differentiation of the four 
known species by reference to test length, test thickness and petal length. 
The genus is of only limited biostratigraphical utility in the late Cenozoic of 
this region. 
INTRODUCTION 
In 1892 the first fossil echinoid was described 
and figured from the western half of Australia by 
J.W. Gregory of the British Museum (Natural 
History) in London. The specimen, described by 
Gregory (1892: 433-435) as "Laganum decagonale, 
Lesson. Var. rictum, n.var." had been sent by the 
Western Australian Government Geologist from 
1888-1895, Harry Page Woodward (McNamara 
and Dodds 1986), to Gregory in London, where it 
was deposited in the British Museum (Natural 
History) and given the catalogue number E3770. 
According to Gregory the specimen was from the 
"Cainozoic of Shark's [sic] Bay, West Australia". 
Another specimen from the same locality was 
retained by Woodward and placed in his collection 
(No.81; WAM 96.208), now housed in the 
palaeontology collections in the Western Australian 
Museum. 
Since being described, this form has variously 
been either raised to specific status (e.g., Clark 
1946) or synonymised with other living species, 
notably a living species, Peronella lesueuri (e.g., 
Mortensen 1948: 271; Logan et al. 1970: 56). Clark 
(1946) recognised that this form belonged in 
Peronella rather than Laganum, on the basis of the 
presence of four, not five, gonopores. However, he 
observed that "ricta . . . must be considered [a] 
Peronella whose specific limits and geographical 
distribution are not satisfactorily known". 
Mortensen (1948), on the contrary, considered the 
Shark Bay form to be very closely related to 
Peronella lesueuri, and "possibly identical with it". 
In their study of the history of carbonate 
sedimentation in Shark Bay, Logan et al. (1970) 
identified it unequivocally as Peronella lesueri [sic]. 
These actions were all taken on the basis of 
Gregory's description and line drawing of the 
specimen, not on the basis of extra material. 
Fieldwork in the Shark Bay region in the 1980s 
by the author has resulted in the collection of 103 
specimens of this echinoid, enabling its specific 
status to be firmly established. Furthermore, 
another species, Peronella orbicularis, also occurs in 
the extensive Pleistocene deposits that outcrop in 
this region (see Kendrick et al. 1991). These two 
species from different Pleistocene units are 
described herein in detail for the first time. 
Pliocene occurrences of Peronella in Western 
Austrlia are restricted to the Roe Calcarenite, 
which outcrops on the Roe Plains in the Eucla 
Basin (Figure 1). Foster and Philip (1980) placed 
this species in the extant Peronella orbicularis. 
However, the Pliocene species has a number of 
characteristics that clearly distinguish it from the 
living species. It is herein described as a new 
species. These Plio-Pleistocene species, including 
true P. orbicularis, are described and their 
stratigraphic distribution, and that of a Holocene 
species of Peronella, discussed. 
BIOSTRATIGRAPHY 
All of the material of Gregory's "Laganum 
decagonale, Lesson. Var. rictum, n.var." was 
collected from the Gladstone Embayment, on the 
