225
members of Epitoniidae in this respect and could point to a parasitic lifestyle
(Bandel 1991; Sasaki 2008) (Fig. 6.3a, b).
Zygopleuridae range from the Early Triassic (Nützel and Schulbert 2005; Foster
et al. 2017) to the Cretaceous (Albian) (Kiel 2006). They closely resemble Palaeozoic
Pseudozygopleuridae but differ in larval ornaments (Bandel 1991; Nützel 1998).
Undoubtedly, both families are closely related to each other and are included in
Pseudozygopleuroidea that may represent the “stem-group” of modern Ptenoglossa
(Bandel 1991; Nützel 1998).
Protorculidae are known from the Early Triassic to the Middle Jurassic, especially from the Carnian Cassian Formation (Bandel 1991; Nützel 1998; Nützel and
Erwin 2002; Kaim and Conti 2010). They have an anterior siphonal channel and
may have a complex teleoconch ornamentation. They share an axially ribbed larval
shell with other Zygopleuroidea as well as with living Nystiellidae and basal
Cerithiopsidae and were identified as fossil sister group of cerithiopsids (Nützel
1998). It is possible that they had acquired a spongivorous lifestyle already.
Donaldinidae and Streptacididae are small, high-spired, sometimes very slender
gastropods with a heterostrophic larval shell. They range from the Devonian to the
Cretaceous but their shell morphology is very close to living genera such as
Murchisoniella or Ebala and it thus might be that they persist until today (Bandel
2005; Warén 2013). Their small size, high diversity but low disparity may point to a
parasitic life style similar to that of living Pyramidellidae.
Amongst the heterogeneous, largely Palaeozoic group Subulitoidea, there are
some diverse genera and families which closely resemble extant parasitic eulimids.
Amongst Meekospiridae (Carboniferous–Permian) the genera Ceraunocochlis and
Meekospira closely resemble recent eulimid species (Fig. 6.2). They share the
smooth surface, shallow suture and high-spired shape and in the case of
Ceraunocochlis the bent spire producing an asymmetrical shape is also present in
several eulimid genera.
6.3 Conclusions
Direct evidence for parasitism of gastropods such as preserved host/parasite associations or characteristic trace fossils in the host is anecdotic at best in relation with
the vast diversity of this class. One of the few exceptions is the Palaeozoic platyceratid/crinoid interaction that has a fairly good record of examples where host and
parasite are still attached to each other and additional borings. Most modern highly
diverse parasitic (or carnivorous grazers) gastropod families have a Late Mesozoic/
Paleocene origin and seem to undergo a major adaptive radiation. At present, taxonomic uniformitarism is the most important tool to infer the fossil record of gastropod parasites. This works for the Cenozoic and Late Mesozoic. Few lines can be
traced into the Jurassic and Triassic with some confidence. Several diverse older,
extinct families of tiny, high-spired Caenogastropoda and Heterobranchia might
have been parasitic but this remains speculative to some degree at this point.
6 Gastropods as Parasites and Carnivorous Grazers: A Major Guild in Marine…
members of Epitoniidae in this respect and could point to a parasitic lifestyle
(Bandel 1991; Sasaki 2008) (Fig. 6.3a, b).
Zygopleuridae range from the Early Triassic (Nützel and Schulbert 2005; Foster
et al. 2017) to the Cretaceous (Albian) (Kiel 2006). They closely resemble Palaeozoic
Pseudozygopleuridae but differ in larval ornaments (Bandel 1991; Nützel 1998).
Undoubtedly, both families are closely related to each other and are included in
Pseudozygopleuroidea that may represent the “stem-group” of modern Ptenoglossa
(Bandel 1991; Nützel 1998).
Protorculidae are known from the Early Triassic to the Middle Jurassic, especially from the Carnian Cassian Formation (Bandel 1991; Nützel 1998; Nützel and
Erwin 2002; Kaim and Conti 2010). They have an anterior siphonal channel and
may have a complex teleoconch ornamentation. They share an axially ribbed larval
shell with other Zygopleuroidea as well as with living Nystiellidae and basal
Cerithiopsidae and were identified as fossil sister group of cerithiopsids (Nützel
1998). It is possible that they had acquired a spongivorous lifestyle already.
Donaldinidae and Streptacididae are small, high-spired, sometimes very slender
gastropods with a heterostrophic larval shell. They range from the Devonian to the
Cretaceous but their shell morphology is very close to living genera such as
Murchisoniella or Ebala and it thus might be that they persist until today (Bandel
2005; Warén 2013). Their small size, high diversity but low disparity may point to a
parasitic life style similar to that of living Pyramidellidae.
Amongst the heterogeneous, largely Palaeozoic group Subulitoidea, there are
some diverse genera and families which closely resemble extant parasitic eulimids.
Amongst Meekospiridae (Carboniferous–Permian) the genera Ceraunocochlis and
Meekospira closely resemble recent eulimid species (Fig. 6.2). They share the
smooth surface, shallow suture and high-spired shape and in the case of
Ceraunocochlis the bent spire producing an asymmetrical shape is also present in
several eulimid genera.
6.3 Conclusions
Direct evidence for parasitism of gastropods such as preserved host/parasite associations or characteristic trace fossils in the host is anecdotic at best in relation with
the vast diversity of this class. One of the few exceptions is the Palaeozoic platyceratid/crinoid interaction that has a fairly good record of examples where host and
parasite are still attached to each other and additional borings. Most modern highly
diverse parasitic (or carnivorous grazers) gastropod families have a Late Mesozoic/
Paleocene origin and seem to undergo a major adaptive radiation. At present, taxonomic uniformitarism is the most important tool to infer the fossil record of gastropod parasites. This works for the Cenozoic and Late Mesozoic. Few lines can be
traced into the Jurassic and Triassic with some confidence. Several diverse older,
extinct families of tiny, high-spired Caenogastropoda and Heterobranchia might
have been parasitic but this remains speculative to some degree at this point.
6 Gastropods as Parasites and Carnivorous Grazers: A Major Guild in Marine…