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Records of the Australian Museum (2017) Vol. 69 
Overview of classification A 
Epitoniidae traditionally has been interpreted as a family of 
benthic gastropods with tall, narrow, white shells, most of 
which have similar sculpture of prominent, widely spaced 
axial lamellae or ridges and, at most, weak spiral sculpture. 
They are well-known for parasitizing benthic cnidarians, 
mainly anemones and corals. However, this is a description 
of species of Epitonium. The illustrations in Weil etal. (1999) 
demonstrate that other benthic epitoniids can be brown, 
red-brown, yellow, or spirally banded brown and white, 
many are much shorter and wider than typical Epitonium 
species, many species are weakly sculptured or smooth, a 
few genera such as Alora H. Adams, 1861 and Eglisia Gray, 
1842 have predominantly spiral sculpture, and many others 
have a combination of axial and spiral sculpture. The fine, 
closely spaced axial ridges on many Janthina species are 
closely similar to those of some finely sculptured Epitonium 
species, and it is the violet colour that sets Janthina species 
apart from Epitonium species strongly at first sight. As the 
violet colour is clearly an adaptation by Janthina to floating 
at the surface of the sea, the obvious first question about 
Janthinidae is whether the family is distinct from Epitoniidae. 
Niitzel (1998: 89) assumed that Janthinidae is a distinct 
family and must be an “old” group of Ptenoglossa with a 
very poor fossil record. Robertson (2007a: 9) also speculated 
that a poor fossil record might have masked an earlier 
history, janthinids and epitoniids having a common ancestor. 
However, Churchill et al. (2011a: fig. 1) demonstrated that 
both Janthina and Recluzia are nested within Epitoniidae in 
a molecular phylogeny (Fig. 3A). Takano & Kano (2014) 
also demonstrated that Janthina umbilicata d’Orbigny, 1841 
belongs in the same clade as Epitoniidae in a molecular 
phylogeny (Fig. 3B). All the writer’s efforts over more 
than 40 years to understand the history of this group have 
demonstrated that the earliest neustonic epitoniid, Janthina 
typica (Bronn, 1861), appeared only during latest Miocene 
(Messinian) time, c. 7-6 Ma, and the genus Janthina 
apparently evolved from a benthic epitoniid and adopted 
the neustonic habit at that time. Janthina is found fossil in 
parts of the world where an extensive, diverse Neogene fossil 
record is preserved and Janthina commonly is stranded on 
beaches at present during persistent onshore winds. In Japan 
and New Zealand the earliest species, J. typica , appeared 
in small numbers in latest Miocene (Messinian) rocks, and 
occurs more commonly in early Pliocene (Zanclean) rocks. 
Supposed late Miocene (Messinian and even purportedly 
Tortonian) records from Santa Maria Island in the Azores 
have all been demonstrated to be Pliocene (early Zanclean, 
5.3^4.3 Ma) through the reorganization of stratigraphy by 
Sibrant et al. (2015). No Miocene specimens are recorded 
from anywhere else, including Australia. The fossil record 
of Janthina is helped by its relatively good preservation 
potential, despite its thinness and fragility, because its outer 
shell layer is calcitic. An interior aragonitic layer is white 
and chalky in many fossils and thickest over the columella. 
The mineralogy of epitoniid shells has been studied little, but 
deserves more attention because of its potential significance 
for phylogeny. It is obvious from the excellent preservation 
of fossil specimens of Cirsotrema species in limestone that 
at least this genus has a calcitic shell. It seems likely that 
all epitoniids have a calcitic outer shell layer, although it is 
possible that some are entirely aragonitic, as are most other 
gastropods. The calcitic shells of Janthina and Recluzia are 
Cypraeidae (outgroup) 
- Calyptraeidae 
■c 
Cerithiopsidae 
Hipponicidae 
— Rissoidae 
- Eulimidae 
■ Littorinidae 
Naticidae 
I— Surrepifungium ingridae 
I— Surrepifungium costulatum 
— Epidendrium sordidum 
I- Epidendrium ancillotoi 
Epidendrium tinctum 
- Cirostrema varicosa 
- Opalia chacei 
r Recluzia cf. jehennei 
- Janthina globosa 
r Janthina exigua 
L Janthina janthina 
B 
- Opaliopsis sp. 
Opalia gracilis 
— Janthina umbilicata 
Alexania inazawai 
- Epitonium replicatum 
- Lyocydus 
- Cheilea 
- Abyssochrysos 
- Vanikoroidea, Rissooidea, Truncatelloidea 
Figure 3. Previously published molecular phylogenies including 
Janthina , Recluzia and Epitoniidae. (A) “Bayesian phylogram of 
Janthinoidea and seven potential sister families. DNA sequence 
data come from four loci: mitochondrial 16S rDNA, nuclear 
28S rDNA, Histone-H3, Histone-H4” (redrawn from Churchill 
et al., 2011a: fig. 1A; name of one Janthina species corrected; 
probabilities etc. deleted), showing Recluzia and Janthina within 
Epitoniidae clade (benthic Epitoniidae: Surrepifungium to Opalia). 
(B) relevant part of diagram “Bayesian phylogeny of Vanikoroidea, 
Truncatelloidea and Rissooidea inferred from 5gGB alignment 
of 28S (Dl-D7b), 18S, H3, 16S and COI genes” (redrawn from 
Takano & Kano, 2014: fig. 2; names corrected; probabilities etc. 
deleted). Epitoniidae (uppermost five taxa) includes Janthina on 
same branch as Alexania. 
surely a reflection of their phylogeny. Distinction between 
Janthina and benthic Epitoniidae based on shell characters 
clearly is superficial; if Janthina species had white shells 
they likely would always have been classified as Epitoniidae. 
All benthic Epitoniidae that have been studied in detail 
are carnivores feeding on cnidarians, mainly anemones 
and scleractinian corals, but a few species feed on other 
