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Records of the Australian Museum (2017) Vol. 69 
successions, resulting from a combination of their oceanic 
positions and strong late Neogene tectonism. Despite the 
very much poorer preservation of fossils, largely due to a 
combination of cementation of the rock and crushing during 
compaction, these longer successions are important for 
dating the evolutionary history of Janthina. Even in these 
active locations, young uplifted successions do not record 
any of the living Janthina species, probably merely because 
late Pliocene-Pleistocene temperatures fell too low for 
Janthina to occur in these northern and southern locations. 
Occurrences in Japan, southern Australia and northern New 
Zealand likely reflect periods influenced by warm currents, 
as well as onshore winds. Other occurrences of Janthina 
fossils, notably at Santa Maria Island in the Azores, at other 
Atlantic islands, Jamaica, in the Philippines, and on the 
mid-Atlantic ridge add usefully to the record of neustonic 
epitoniid evolution. A few other records might be expected in 
future from such localities as the Philippine Islands or Italy 
where young rocks and active tectonism provide suitable 
conditions for the preservation of Janthina fossils in warm 
locations. Fossils from Madeira and Selvagem Grande Island 
also need to be investigated. Occasional chance records like 
those from off Brazil and at Kane Megamullion on the mid- 
Atlantic ridge will also result from deep-sea dredging and 
possibly from coring, but fossils of Janthina are common 
on land only in New Zealand, Japan and, in particular, along 
the southern coast of Australia. 
Coeval with the time range of Janthina chavani, J. 
globosa had evolved by Piacenzian-Gelasian time and is 
recorded from two widely separated localities, in Jamaica 
and the Philippine Islands (see below under J. globosa). 
Unfortunately, the ages of these localities are not closely 
constrained within Piacenzian-Gelasian time, and the 
relationship of these specimens of J. globosa to the evolution 
of J. chavani is unknown. The main speciation event of 
potential biostratigraphical utility identified here within 
Janthina , when J. chavani replaced J. typica abruptly 
throughout the world ocean, possibly was brought about by 
cooling at the end of the Pliocene climatic optimum. The 
climatic optimum was identified by Dowsett et al. (2013) 
as mid-Piacenzian, occupying 3.2-3.0 Ma. The earliest 
record of J. globosa at about this time might also not be a 
coincidence. 
Based on the stratigraphical successions described above, 
time ranges of the species of Janthina are: 
1 Janthina typica\ latest Miocene-early late Pliocene 
(Messinian, Zanclean and early Piacenzian Stages), 
Kapitean, Opoitian and Waipipian New Zealand Stages; 
c. 7-3.0 Ma; time of first appearance poorly constrained, 
possibly nearer 6 than 7 Ma. 
2 Janthina chavani'. late Pliocene-early Pleistocene (late 
Piacenzian-early Calabrian Stages); Mangapanian New 
Zealand Stage and most of the Nukumaruan New Zealand 
Stage; upper limit uncertain, extending well into the 
expanded Pleistocene, to at least MIS 61 (1.75 Ma, early 
Calabrian). In the Mohaka River section, northern Hawke’s 
Bay, New Zealand, J. chavani succeeded J. typica at the 
Waipipian-Mangapanian Stage boundary, at 3.0 Ma in mid- 
Piacenzian time, and the Janthina succession on Kangaroo 
Island, South Australia, appears to correlate directly with 
this; 3.0-c. 1.7 Ma (probably significantly younger, c. 1 
Ma?, in Bridgewater Limestone in SE South Australia), 
upper limit not constrained. 
3 Janthina krejcii sp. nov.: early Pliocene (Zanclean), 
recognized definitely so far only on Santa Maria Island, 
Azores. Possibly a restricted Atlantic species, but more 
likely limited to a time range not represented in other rocks 
containing fossil neustonic Epitoniidae; c. 4.8^.3 Ma at 
the type locality. 
4 Janthina globosa'. Late Piacenzian or Gelasian-present- 
day; earliest appearance poorly constrained. 
5 Janthina janthina : Reported fossil only from Holocene 
rocks in New Zealand, and from late Pleistocene-Holocene 
core-top samples in the Red Sea (Janssen, 2007a, b), the 
eastern Mediterranean (Janssen, 2012: 25) and probably 
the Cariaco Basin, Venezuela (Jung, 1975); present day. 
6 All other Janthina and Recluzia species have no fossil 
record. 
The successions described above are summarized in Fig. 
22 to provide correlations of Janthina species time ranges 
with international stages, biostratigraphical zonations and 
geomagnetic polarity stratigraphy. 
Evolutionary history 
Because of the almost cosmopolitan ranges of all living 
Janthina species in water warmer than 10°C, it is assumed 
here that all earlier species also were cosmopolitan in the 
same temperature range. It is also assumed that the fossils 
represent a single clade, and that all extinct species have 
now been recognised. Obviously, the addition of further 
species would alter the phylogeny significantly. The 
stratigraphical successions described above demonstrate 
that the earliest neustonic epitoniid was Janthina typica. 
This species occurs in the Touril Complex on Santa Maria 
Island (Zanclean, 5.33^1.32 Ma) and in the latest Miocene 
(Kapitean, Messinian) and early to early late Pliocene 
(Opoitian-Waipipian; Zanclean-early Piacenzian) in New 
Zealand. The same time range is confirmed, less precisely, in 
Australia and Japan; Japanese late Miocene records probably 
extend a little earlier than New Zealand ones. Janthina typica 
has evenly rounded whorls and a moderately and consistently 
low spire, similar in size and shape to the widespread “garden 
snail” Cornu aspersum (Linnaeus, 1758). It has a lower spire 
and fewer whorls than C. aspersum , with prominent spiral 
folds in the shell wall, uniform fine axial ridgelets over the 
entire teleoconch, and an obvious, small, semicircular sinus 
in the base of the outer lip. Janthina typica was succeeded 
abruptly at 3.0 Ma by J. chavani , which ranges through late 
Pliocene-Pleistocene (late Piacenzian-Calabrian) rocks. 
Specimens of J. chavani have a taller, flatter sutural ramp 
and most specimens have weaker spiral folds than in J. 
typica and at least the uppermost two spiral folds on the 
sutural ramp of J. typica are suppressed in J. chavani. In 
other characters it is almost identical to J. typica , except that 
larger specimens have taller spires than smaller ones, much 
more obviously than in J. typica. On Santa Maria Island a 
previously undescribed species, Janthina krejcii sp. nov., 
apparently replaced J. typica relatively high in the Touril 
Complex, although its time range elsewhere demonstrates 
that J. typica continued on and did not become extinct at 
the origination of J. krejcii. The type locality, at the lookout 
(Miradouro de Macela) on the road from Almagreira to Praia, 
is at a similar elevation to the locality at Cre described by 
Janssen et al. (2008), where pteropods confirm a Zanclean 
