A new species of Peribrissus (Echinoidea, Spatangoida) from the middle Miocene of South Australia 
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to Peribrissus, the diagnosis given for the genus applies also to 
the species, thus satisfying the criteria for availability (ICZN, 
Article 12.2.6) and making P. saheliensis the type species by 
subsequent monotypy (ICZN, Article 68.3). 
Two species of Pericosmus described by McNamara and 
Philip (1964) from the Miocene of Australia — P. celsus and 
P. quasimodo — were reassigned by Smith et al. (2005) to 
Peribrissus. Though Pericosmus and Peribrissus are 
superficially alike, the path of the peripetalous fasciole in the 
two Australian species is clearly different from that in the 
Prenasteridae and, consequently, in Peribrissus. Smith et al. 
(2005) stated that in the Prenasteridae, ‘marginal and 
peripetalous fasciole combine anteriorly, the combined band 
passing several plates below the end of the anterior petals’. In 
contrast, the peripetalous fasciole in Pericosmus celsus and P. 
quasimodo — as well as in P. torus, also erected by McNamara 
and Philip in the same paper — follow a distinctly different 
path. These three species have the peripetalous fasciole closely 
bounding the distal end of the anterior petals, then transversely 
crossing interambulacral plates in columns 2a and 3b before 
taking a longitudinal path (sometimes irregular and/or 
intermittent) towards the marginal fasciole in interambulacral 
columns 2b and 3a. Due to the state of preservation of the 
numerous Pericosmus specimens inspected in Museum 
Victoria and private collections, it is not possible to determine 
whether the peripetalous fasciole always reaches the marginal 
fasciole on either side of the anterior sulcus. Nevertheless, in 
all Australian species assigned to Pericosmus, including P. 
compressus Duncan, 1877 and P. maccoyi Gregory, 1890, the 
peripetalous fasciole closely bounds the distal end of the 
anterior petals and continues transversely onto interambulacra 
2 and 3, clearly negating any reassignment to Peribrissus. 
However, whether the five Australian fossil species listed 
above strictly belong in the genus Pericosmus is a matter of 
conjecture, considering the type species Pericosmus latus 
Desor in Agassiz and Desor, 1847, has separate and continuous 
marginal and peripetalous fascioles, the latter crossing 
ambulacrum III well above the anterior margin. 
Stefanini (1911, p. 86) reassigned Prenaster excentricus 
(Wright, 1855) to Peribrissus in the belief that the two genera 
overlap based on the similarity of their upper test profile with 
highly eccentric anterior apex and four ethmolitic genital 
pores. Pomel’s statement (1887, p. 63) — that the number of 
genital pores in Peribrissus is unknown — seems to have been 
ignored by Stefanini, whose reference to four genital pores 
may have been based on details of Wright’s species. Giorgio 
(1923, p. 125), in describing Peribrissus sotgiai from Sardinia, 
accepted Stefanini’s finding that Wright’s Prenaster from 
Malta was a Peribrissus ; noting that P. sotgiai has four 
gonopores, but that the right anterior one is poor and almost 
atrophied. These statements appear to have resulted in 
Mortensen (1951) and Fischer (1966) listing both genera as 
having four genital pores. However, of the eight genera now 
included in the family Prenasteridae by Smith et al. (2005), 
only Peribrissus and Tripylus Philippi, 1845 are listed as 
having three genital pores. Although both of these genera have 
a well-defined anterior sulcus, Peribrissus is easily 
distinguished from Tripylus by the markedly anterior location 
of its apical disk compared to the central position in the latter. 
The lack of a sulcus and the presence of four genital pores in 
species of Prenaster clearly refute Stefanini’s reassignment of 
Prenaster excentricus to Peribrissus. 
Peribrissus janiceae sp. nov. 
Figures 2A-E, 3A-I, Table 1 
Type material. Holotype and only known specimen, NMV P316528, 
from the early middle Miocene Glenforslan Formation (Batesfordian, 
Langian), Morgan Group, 7 km north-northeast of Murray River Lock 
1, Blanchetown , South Australia [NMV locality PL3203]. 
Description. Test moderately large, ovate in outline with well- 
formed anterior sulcus; only known specimen 58.0 mm long, 
with maximum width of 52.0 mm (89.7%TL) occurring 
posterior of centre at 54.3%TL from anterior ambitus. 
Maximum test height 38.5 mm (66.4%TL) anterior of centre, 
but posterior of apical disk at 44.8%TL from anterior ambitus. 
Adapical surface inflated with high, vertically convex 
anterior, gently curved ridge along interradial suture of 
interambulacrum 5 and prominent vertically truncated 
posterior. Laterally, sides gently curved at approximately 40° 
to the horizontal between dorsal ridge and well-rounded 
ambitus situated about one-third test height above the 
underside. Adoral surface posterior of peristome flat along 
centre line of labrum and plaston (fig. 2C-E). 
Small, very closely spaced tubercles cover nearly all the 
test; smallest around ambitus and largest towards peristome. 
Figure 2. Peribrissus janiceae sp. nov. A-E, outline drawings of 
adapical, adoral, left lateral, anterior and posterior views of holotype 
NMV P316528, showing paths followed by marginal (mf) and 
semipetalous (spf) fascioles, and position of peristome (pse) and 
periproct (ppt). 
