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The Problem with Siphocypraea

MikeR

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For millennia, humankind has been fascinated by the hard-external shell of the organisms classified within the Phylum Mollusca.   Consumed first as food, their empty shells have served multiple functions in the past; as tools in many ancient cultures, in religious ceremonies by the Aztecs, and money by Pacific Islanders. During the Age of Discovery, sailors could supplement their meager incomes by selling exotic seashells to wealthy gentlemen for their Cabinets of Curiosity.  Today many people first become enchanted with seashells by picking up worn beached shells during a vacation to the shore.  If fortunate to live by the ocean, a newbie might branch off into the live collection of shallow water mollusks while those more land bound might start by purchasing foreign, deep-water or rare specimens.  Because of the shear abundance of marine mollusk species, the more advanced collector will begin to concentrate on a single or small number of molluscan families, acquiring as many of those species as possible, spending major capital for the rarest.  Among the gastropods, one of the most popular families to collect due to its beauty are species of the family Cypraeidae commonly known as the cowries.  Members of this family are known for their egg shaped, brightly colored shells with a narrow slit-like aperture and most notably a porcelain-like glossy shell that is produced by the animal’s soft mantle which when fully extended, covers and polishes the external shell.  Cowries are common worldwide across tropical and subtropical seas even with a few temperate species tolerant of colder water.  Because of their popularity as a biologic collectible, the desire to create new species with minute differences or found at diverse localities have resulted in a large amount of species splitting.  Fabio Moretzson (2014) termed this as taxonomic ‘noise’, much of it from non-peer reviewed amateur publications with new species descriptions based mostly on shell characteristics.  Moretzsohn and the editorial board of the World Register of Marine Species (WoRMS) have attempted to clean up much of the ‘noise’ through review of molecular and anatomical data reducing over 1000 different names to 245 species and 166 subspecies (2013).


Paleontology is not immune to the proclivities of the cowrie collector.  Going back to at least the Cretaceous, fossil Cypraeidae are also sought and commercially sold with notable species found in the Eocene and Oligocene of Europe, the Miocene of Indonesia, and the Oligocene and Miocene of Australia.  In general, fossil cowries are rare with the notable exception of the genus Siphocypraea from the Upper Pliocene of the Southeastern United States.  Unlike other cowries which have a distinct spire in their immature bulla stage, Siphocypraea has a depression over the apex resulting in either an open or spiral apical sulcus in adults.  Anyone who has collected from the Plio-Pleistocene shell pits of South Florida has encountered these shells in abundance with a staggering amount of variation in characteristics.  In this post, I will review the publication history of Siphocypraea and in doing so describe the different interpretations of its speciation.


T.A. Conrad (1841) described one of the first fossil cowries found in the United States from a specimen discovered at a sink hole in Duplin County, North Carolina.  This species that he named Cypraea carolinensis, was listed from Miocene deposits now considered as Upper Pliocene Duplin Formation.  Later in 1886 Angelo Heilprin in his paleontological explorations of South Florida described a cowrie found within Pliocene (now considered Lower Pleistocene) marl deposits uncovered in canal construction along the Caloosahatchee River.  Due to its unusual comma-shaped apical sulcus, he named it Cypraea (Siphocypraea) problematica.  At this point in time, no other Neogene cowries were described for almost 50 years.  The Florida development boom began in the early 20th Century and during the construction of the Tamiami Trail connecting Florida’s west and east coasts, draglines encountered a molluscan rich sand near the Monroe-Dade County line.  Among the endemic Miocene (today Pliocene) fauna were large cowries which W.C. Mansfield noticed were very similar to the species found in North Carolina.  Mansfield (1931) named it Cypraea carolinensis floridana differing from the type by being more elongated and having a rounder ventral area.  The following year Mansfield described a near perfect specimen of C. carolinensis carolinensis from what is now called the Jackson Bluff Formation thereby extending its range to the Florida Panhandle.  The German malacologist F.A. Schilder (1932) noting similarities between Cypraea mus, a recent Venezuelan species and Heilprin’s Cypraea (Siphocypraea) problematica assigned C. mus to the subgenera Siphocypraea.  Woodring (1959) would disagree with placing C. mus into Siphocypraea instead, he created a new subgenera Muracypraea for C. mus and its associated fossil species.  Disregarding a similar bulla stage apical depression with C. carolinensis, Julia Gardner (1948) in her monograph of the Miocene and Pliocene molluscan fauna of North Carolina and Virginia, proposed a new section name, Akleistostoma for C. carolinensis and C. mus.  


One of the more seminal works in Florida biostratigraphy and paleontology in the 1960s was by Alex Olsson and Richard Petit (1964).  In Part 1 Olsson clarified the stratigraphy and associated fossils that were being exposed in shell pits, new canals, and the channelization of the Kissimmee River, by dividing the Neogene of Florida into four units: The Tamimi Limestone in Unit D, the Pinecrest in Unit C, the Caloosahatchee in Unit B and an unnamed Unit A which would later be known as the Bermont Formation and allied these units to their Mid-Atlantic counterparts.  In Part 2, Olsson and Petit named new species and correlated known species into their corresponding unit.  In the process they raised Siphocypraea to genus level noting the extreme variation seen in the genus particularly in the Kissimmee River area.  They questioned how many of these variants should be named but did find two forms that were numerous enough to assign as subspecies of S. carolinensis; S. carolinensis hughesi a very broad elliptical form and S. carolinensis transitoria which shows characteristics transitional between S. carolinensis and S. floridana.  Later Olsson and Petit (1968) expanded upon their views on Siphocypraea by assigning Cypraea mus as Siphocypraea (Muracypraea) mus and reassigning Cypraea chilona found in the Miocene Chipola Formation as Siphocypraea chilona.


No other United States Siphocypraea were described until the work of Ed Petuch began in the late 1970s first with the description of a new extant species within the Caribbean.  Petuch worked in the Florida Neogene at a time when many pits and construction projects were exposing sediments containing species new to science.  One of these exposures was in a housing project west of Miami in which the digging of a lake exposed a fossil shell deposit with mollusks having close affinities to the Upper Pliocene of the Mid-Atlantic region.  Among the new species was a Cypraea in which Petuch (1986) named C. lindae.  Also found were a diminutive cowrie which he associated with Cypraea pilsbryi an obscure species named by Ingram (1939) from the Cape Fear River in North Carolina.  Petuch (1994) would later reassign both to Siphocypraea.  During this era, Petuch was not the only researcher naming new Siphocypraea species.  In 1988 Juan Parodiz of the Carnegie named a species with similarities in between S. carolinensis and S. problematica naming it S. trippeana.  Within the same paper Parodiz elevated Olsson and Petit’s subspecies S. transitoria and S. hughesi to species level.  In 1991, Petuch named three additional Siphocypraea; S. mulepenensis, S. griffini and S. herweckorum, however it was with the release of his Atlas of Florida Fossil Shells in which the naming of species really began to exponentially increase.  Without going through each individual name, Petuch (1994) named 12 new Siphocypraea species, followed by his 1996 publication creating a new genera Calusacypraea for those Siphocypraea which exhibit neotenic (juvenile traits in adult form) moving his S. sarasotaensis into this generic assignment and naming three new species.  Before the 20th Century concluded, a German researcher, Dirk Fehse (1997) named two additional Siphocypraea species from the Caloosahatchee Formation.


The number of Siphocypraea species were artificially reduced by Petuch (2004) when he resurrected Gardner’s Akleistostoma as a genus for all Siphocypraea having a simple anterior sulcus with a widely opening posterior aperture and a new genus, Pseudadusta for those species with a comma shaped anterior sulcus and a narrow posterior aperture.  In addition, and without going into much detail here, within the same publication he created a new subgenus within Calusacypraea called Myakkacypraea and two new subgenera within Siphocypraea; Okeechobea and Pahayokea.  Within this entire Siphocypraea complex he named nine new species.  In his book on the Geology of the Everglades, Petuch (2007) pictured two internal casts, one Akleistostoma and the other Calusacypraea from the Lower Pliocene Peace River Formation which if accurate fills in a large gap between the Chipola species S. chilona and the Upper Pliocene S. carolinensis.  Naming of new species continued in Petuch’s unpublished book Compendium of Florida fossil shells (2011).  He gave a name to the Akleistostoma internal cast and named four new subgenera to Akleistostoma and 13 new Pliocene species.  For Siphocypraea he created three new subgenera and 11 species while upgrading his two Siphocypraea subgerera from 2003 to genus level.  Thus, genus Pahayokea has two new subgenera and six new species and genus Okeechobea one new subgenus and eight new species.  For Calusacypraea, the Miocene cast, one new subgenus and one new Pliocene species were named.  Lastly with his genus Pseudadusta Petuch named two new subgenera and 11 new species.  In all 52 new species of the Siphocypraea complex were named in this one work.  Just last year Petuch (2018) published his latest book concentrating solely on the fossil Cypraeidae of South Florida.  I have yet to acquire this book, however it advertises the description of over 100 species, so there must be additional new species that would add to this total, three that I know of for sure.

 

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WoRMS has tried to cleanup some of this taxonomic splitting by failing to recognize any of Petuch’s genera instead accepting only Siphocypraea and Akleistostoma.  Also, they have upgraded the Caribbean fossil and extant species classified under Siphocypraea (Muracypraea) to full genus recognition as Muracypraea.  Under this interpretation, Siphocypraea/Akleistostoma were restricted to the flooded Southeastern United States and became extinct with S. problematica in the Lower Pleistocene.  WoRMS did not challenge the 90-species listed prior to 2018 as it is a register for extant species however its acceptance of Akleistostoma has caused some problems with the systematics of Siphocypraea.  As defined by Gardner, Cypraea carolinensis would be Akleistostoma carolinensis and as defined by Petuch any Cypraeidae with a simple anterior sulcus.  Heilprin’s definition of Siphocypraea could therefore be interpreted broadly as any Cypraeidae with a comma shaped anterior sulcus.  There are many workers of Florida molluscan paleontology that except this believing that there are only two species; carolinensis and problematica.  However, to accept that viewpoint is to ignore the transitional forms and variation that was occurring in South Florida during the Upper Pliocene.  Accepting Olsson & Petit’s view that Gardner created an unnecessary classification with Akleistostoma and that the depressed apex in the Bulla stage is the defining characteristic in Siphocypraea would clarify the inconsistencies with the evolution of S. carolinensis/floridana to the endpoint S. problematica.  It is why I have chosen to use only Siphocypraea in my collection.


The ultimate question is how many species of Siphocypraea are there?  That is not the scope of this post and would require a lot of work which would certainly be contested and contentious.  I do believe there are more than five and less than hundred.  I believe all species up to Olsson and Petit.  I believe that some of Petuch’s species are valid, but exactly which ones are hard to say.  His practice of creating subgenera that he later elevates to genus and description of species within depositional beds and those interpreted beds in different geographically regions make it difficult to say which are species and which are synonyms.  What I have tried to do below is to bin different characters and variations of Siphocypraea within my collection from degree of anterior sulcus coiling and the opening of the posterior aperture.

 

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Siphocypraea chilona (Dall, 1890). Lower Miocene (Burdigalian) Chipola Formation, Liberty County, Florida USA.  Shell is nearly round with a high convex dorsum and a narrow aperture uniform throughout.  Even crenulations of both sides of the aperture.  When preserved, the color pattern is of large reddish spots.  Not uncommon at Alum Bluff.  Both WoRMS and Petuch would assign this species to the genus Akleistostoma.

 

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Siphocypraea carolinensis (Conrad, 1841). Upper Pliocene Duplin Formation.  Left: Darlington County, South Carolina USA.  Right: Florence County, South Carolina USA.  The specimen on the left is typical of S. carolinensis, subovate with a simple anterior sulcus, wide posterior aperture, denticles on parietal lip are weak.  The dorsum or top of shell can be variable with some gerontic specimens being relatively high.  The dorsum height of the specimen on the right is closer to S. floridana but all other characteristics are consistent with S. carolinensis.  Also, Akleistostoma.

 

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Siphocypraea pilsbryi (Ingram, 1939). Upper Pliocene Duplin Formation, Bladen County, North Carolina USA.  The best way to describe this species is as a miniature S. carolinensis.  I had this listed as a dwarf form of S. carolinensis until I came upon the paper describing Cypraea pilsbryi in researching this post.  The type locality is the Cape Fear River and I found several examples of this species on a tributary of the Cape Fear.  Little is found online about this species although Petuch has reported it from South Florida.  Also, Akleistostoma.

 

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Siphocypraea carolinensis floridana (Mansfield, 1931).  Upper Pliocene Pinecrest Sand Member of the Tamiami Formation, Sarasota County, Florida USA.  The specimen on the left is a gerontic individual from APAC, on the right typical S. floridana from SMR.  Highly variable much more so than S. carolinensis.  The dorsum tends to be not as high as S. carolinensis and parietal denticles are more strongly expressed but shares the uncoiled anterior sulcus and wide posterior aperture.  This is the common Siphocypraea found in the Sarasota shell pits.  Also, Akleistostoma.

 

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Siphocypraea sarasotaensis Petuch, 1994.  Upper Pliocene Pinecrest Sand Member of the Tamiami Formation, Sarasota County, Florida USA.  First described as a Siphocypraea, Petuch later classified this species with his Calusacypraea genus which is defined by neotenic characteristics such as an undeveloped anterior sulcus and very light weight.  Many researchers feel that this species is merely a variation of S. floridana (Lyle Campbell pers. comm.).  WoRMS classification Akleistostoma while Petuch would call this species Calusacypraea myakka.

 

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Siphocypraea briani (Petuch, 1994).  Upper Pliocene Pinecrest Sand Member of the Tamiami Formation, Sarasota County, Florida USA.  Described as Calusacypraea briani and differentiated from S. sarasotaensis by having a larger and longer shell.  I have placed this shell as S. briani however it could be a gerontic individual of S. sarasotaensis.  Some Cypraeidae demonstrate sexual dimorphism which could explain the larger size as well.  WoRMS classification Akleistostoma, Petuch Calusacypraea.

 

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Siphocypraea lindae (Petuch, 1986).  Upper Pliocene Golden Gate Member of the Tamiami Formation, Collier County, Florida USA.  Very close to S. carolinensis with a high dorsum and simple sulcus but with a narrower posterior aperture and stronger denticles on parietal lip.  Petuch assigns this species in his genus Pseudadusta.

 

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Siphocypraea trippeana Parodiz, 1988.  Upper Pliocene Pinecrest Sand Member of the Tamiami Formation, Sarasota County, Florida USA.  Typically, shell is small and narrow with a high dorsum.  The sulcus has a slight bend more so than the S. carolinensis complex, described as a keyhole appearance and a narrow aperture like S. problematica.

 

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Siphocypraea ketteri Petuch, 1994.  Upper Pliocene Golden Gate Member of the Tamiami Formation, Collier County, Florida USA.  Another form transitional between S. carolinensis and S. problematica.  Differs from S. trippeana by having a wider shell and flattened base with noticeable wrinkles along the base.  Petuch assigns this species in the genus Pseudadusta.

 

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Siphocypraea hughesi Olsson & Petit, 1964.  Upper Pliocene Pinecrest Sand Member of the Tamiami Formation, Highlands County, Florida USA.  Restricted to the Kissimmee River area.  Distinctive shape, wide and squat.  Anterior sulcus approaching that of S. problematica.  Petuch assigns this species to Akleistostoma (Olssonicypraea).

 

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Siphocypraea transitoria Olsson & Petit, 1964.  Upper Pliocene Pinecrest Sand Member of the Tamiami Formation, Sarasota County, Florida USA.  Although common in the Kissimmee River area, this specimen is from APAC in Sarasota where it is much rarer.  Very close to S. problematica with slightly less coiling of the anterior sulcus and a slightly wider posterior aperture.  Petuch would call this Siphocypraea streami.

 

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Siphocypraea mulepenensis Petuch, 1994.  Upper Pliocene Golden Gate Member of the Tamiami Formation, Collier County, Florida USA.  Like S. problematica with a comma shaped anterior sulcus and narrow aperture.  The shell differs in being shorter with a pyriform shape. The shell around the anterior sulcus noticeably protrudes.

 

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Siphocypraea problematica (Heilprin, 1886).  Lower Pleistocene (Calabrian) Caloosahatchee Formation, Martin County, Florida USA.  The shell is long and narrow with a comma-shaped anterior sulcus and narrow posterior aperture.  Well preserved individuals demonstrate a rich golden color.

 

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Siphocypraea swearingeni Petuch & Drolshagen, 2011.  Lower Pleistocene (Calabrian) Caloosahatchee Formation, Martin County, Florida USA.  I found numerous specimens of this form in mixed spoil with the S. problematica pictured above and based on the adhering matrix, it appears that they came from a different layer.  Wider and shorter than S. problematica, this could be an environmental variant of it.  I was hesitant to put a Petuch 2011 name on this population as there could very well be an earlier name that would take precedent, however it does fit very closely to the figures of S. swearingeni in Petuch 2018.

 

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Muracypraea mus (Linnaeus, 1754).  Recent.  Judibana Bay, Venezuela in sea grass beds at 1-3 feet depth.  Also known as the mouse cowrie, this species was once classified as Siphocypraea.  Since M. mus has two obvious nodes on each side of the mantle line on posterior end of the dorsum and the sulcus fills with callous as it matures, it was placed within a separate genus.  Although restricted to Venezuela and Eastern Columbia, its ancestor M. henekeni had a widespread Caribbean distribution in the Miocene.  


REFERENCES
Conrad, T. A.   1841.  Appendix to: Observations on the Secondary and Tertiary formations of the southern Atlantic States, by James T. Hodge.  Am. Journ. Sci., vol. xli, 1st ser., pp. 332-348.
Dirk Fehse.  1997.  Two new fossil Siphocypraea from Florida, U.S.A. - Schriften zur Malakozoologie, Heft 10: 38-44, pl. 12-13, 1 tab.


Gardner, J. A. 1948. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina: Part 2. Scaphopoda and Gastropoda, United States Geological Survey Professional Paper 199-B: iv, pages 179-310, plates 24-38, [iii].


Heilprin, Angelo.  1887.  Explorations on the west coast of Florida and in the Okeechobee wilderness: with special reference to the geology and zoology of the Floridian peninsula: a narrative of researches undertaken under the auspices of the Wagner Free Institute of Science of Philadelphia.  Transactions of the Wagner Free Institute of Science of Philadelphia v. 1

 

Ingram, W. M. 1939. A new fossil cowry from North Carolina. The Nautilus 52(4):120-121.


Mansfield, W.C. 1930. Miocene Gastropods and Scaphopods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 3, 189 pages.


Mansfield, W.C. 1931. Some tertiary mollusks from southern Florida. Proceedings of the United States National Museum, v. 79.


Moretzson, Fabio.  2014.  Cypraeidae: How well-inventoried is the best-known seashell family?  American Malacological Bulletin. 32(2): 278-289.


Olsson, A.A., and R.E. Petit. 1964. Some Neogene Mollusca from Florida and the Carolinas, Bulletins of American Paleontology 47(217): pages 509-574, plates 77-83


Olsson, A.A., and R.E. Petit. 1968 (1993 Reprint). Notes on Siphocypraea, Originally - Special Publication 9, The Paleontological Research Institute Special Publication 19: pages 77-88.


Parodiz, J.J. 1988. A new species of Siphocypraea (Gastropoda, Cypraeidae) from the Neogene of southwest Florida. Annals of the Carnegie Museum 57(3): 91–97.


Petuch, Edward J. 1979. A New Species of Siphocypraea (Gastropoda: Cypraeidae) from Northern South America with Notes on the Genus in the Caribbean.  Bulletin of Marine Science -Miami- 29(2):216-225.


Petuch, Edward J. 1986. Cenozoic The Pliocene reefs of Miami: their geomorphological significance in the evolution of the Atlantic Coastal Ridge, southeastern Florida, USA.  Journal of Coastal Research 2(4).


Petuch, Edward J. 1991, New Gastropods from the Plio-Pleistocene of Southwestern Florida and the Everglades Basin.  W.H. Dall Paleontological Research Center Special Publication Number 1. 


Petuch, Edward J. 1994. Atlas of Florida Fossil Shells (Pliocene and Pleistocene Marine Gastropods). Chicago Spectrum Press.


Petuch, Edward J. 1996. Calusacypraea, a new, possibly neotenic genus of cowries from the Pliocene of southern Florida. Nautilus 110(1): 17-21

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Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.


Petuch, Edward J. 2007. The Geology of the Everglades and Adjacent Areas. CRC Press.


Petuch, Edward J. and Mardie Drolshagen.  2011.  Compendium of Florida Fossil Shells, Vol. 1 Middle Miocene to Late Pleistocene Marine Gastropods: Families Strombidae, Cypraeidae, Ovulidae, Eocypraeidae, Triviidae, Conidae, and Conilithidae [unpublished].


Petuch, Edward J. David P. Berschauer, Robert F. Myers.  2018.  Jewels of the Everglades: The Fossil Cowries of Southern Florida.  San Diego Shell Club, 256 pp.

 

Schilder, F.A.  1932.  Fossilium Catalogus, I, Animalia.  Pars 55.  Cypraeacea, 276 pp.


Woodring, Wendell Phillips.  1957.  Muracypraea, new subgenus of Cypraea: Nautilus, v. 70, no. 3, p. 88–90,



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An outstanding example of well researched analytical writing!  If only others that arbitrarily erect new species were as thorough.  Well done, Mike.

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