Palaeos Palaeos Gastropoda
Mollusca Euomphaloidea

Gastropoda

Abbreviated Dendrogram
MOLLUSCA
|--ACULIFERA
`--CONCHIFERA
   `==Helcionelloida
      `--+--Bellerophontoidea
         `--GASTROPODA  (crown group)  
            |==Eogastropoda  (paraphyletic or polyphyletic) 
            |  |?--Macluritoidea
            |  |?--Euomphaloidea
            |  `--Patellogastropoda
            `--Orthogastropoda  
               |--Vetigastropoda
               |--Neritimorpha
               `--+--Caenogastropoda
                  `--Heterobranchia
                     |--Opisthobranchia
                     `--Pulmonata
Contents

Index
Overview
Gastropod radulas
Systematics Gastropoda
Eogastropoda
Macluritoidea
Euomphaloidea
Patellogastropoda
Orthogastropoda
Vetigastropoda
Neritimorpha
Glossary
Dendrogram
References


Taxa on This Page

  1. Euomphaloidea


Introduction

The Euomphalids (originally Euomphalacea or Euomphalina ) are an important Paleozoic clade of low-spired to planispiral gastropods, some of which, like the macluritids, are hyperstrophic. They are very abundant in some Paleozoic formations and include useful index fossils.  Moore, et al. (1952). Some lived lifestyles like modern gastropods, others it seems were sedentary filter-feeders.

The group was originally considered a superfamily of Archaeogastropoda, and according to Knight et al. (1954), evolved from macluritids, with which they seem to be clearly related. Linsley & Kier (1984) tentatively place them, along with the Macluritoidea, in the Paragastropoda.  But Wagner (1999) derives both groups from ophiletids, although they seem to have diverged very early.

The group as originally defined had two peaks of development, one in the Devonian and another in the Triassic (finally dying out in the Cretaceous) , but these would seem to be actually two distinct stocks.  Moore, et al. (1952).  The Palaeozoic forms are true Euomphalids, whereas the Mesozoic taxa appear to be derived trochoids.  Bandel (1988).  Examination of shell mineralogy, larval shells, and teleoconchs (adult shells) confirm that the Euomphalacea/Euomphaloidea, like the Bellerophontoidea and other extinct taxa, are polyphyleticWagner (2001).

Not only are many species formerly considered Euomphalids not really related, but it seems that other forms that have previously been thought of as having different origins actually are. Studies also indicate that many Paleozoic Palaeotrochoidea (placed in the Trochina -- now included in the Vetigastropoda -- by Knight, et al., 1960) are a polyphyletic assemblage related to the euomphaloids.  Wagner (2001).  Ponder and Lindberg (1996, 1997) suggest that palaeotrochoids and vet gastropod trochoids are only distantly related. According to Wagner (1999), both palaeotrochoids and traditionally placed euomphaloid planispiral taxa arose at least six times each in the Ordovician and Silurian, mostly within the same clade.  Wagner (2001).


Early gastropod phylogeny

Relationships of major extant gastropod clades are largely based on the 50% majority consensus tree of Ponder and Lindberg (1997). Since this does not include a comprehensive phylogenetic analysis, the fossil taxa are included here with reservations. Assignments are based on the resemblance of a few features (e.g. the Peruneloidea resemble caenogastropods in teleoconch shape and the platyceratids have an outer calcitic layer like many neritopsines). Two possible positions of the euomphalids are suggested. Although other possible arrangements might be as likely, it is clear that umbilicate or openly coiled protoconchs (indicated by rectangles) are present in different clades and connected with different teleoconch morphologies. - dendrogram and caption from Nutzel (2002).

Recent study of the the protoconch of Carboniferous euomphalids in far greater detail by Nutzel (2002) reveals that the protoconch (larval shell) less than one planispiral whorl that is umbilicated or openly coiled, before a sudden transition to the teleoconch (adult shell). The euomphalid protoconch is umbilicate (openly coiled) and bilaterally symmetrical. Similar protoconchs are present in Recent species of the Cocculiniformia, the Neomphalidae and the Docoglossa (Patellogastropoda). This conforms a previously suggested close phylogenetic relationship between the euomphalids and extant limpets. The fact that several other Palaeozoic gastropod clades, unlike most modern gastropods, also have an openly coiled initial whorl is remarkable, and it is only the planispiral shape of the euomphalid protoconch that distingusihes these gastropods. The relevance of the distinctive paleozoic protoconch for the phylogeny and the systematics of the Gastropoda is not yet clear. MAK120621

Euomphalida Dendrogram

The following dendrogram is copied from Mikko Haraamo pages

<== o EUOMPHALINA de Koninck, 1881
   |-- Prohelicotoma
   |-- Ophileta subraplana
   `--+-- Ophileta complanata
      `--+-- Lecanospira compacta
         |-- Lecanospira nereine
         `--+-- Barnesella ?lecanospiroides
            |--o Ecculiomphalus Portlock, 1843
            |  |-- Malayaspira rugosa
            |  `--+-- MACLURITOIDEA Fischer, 1885
            |     `--+-- Malayaspira hintzei
            |        |--+--+-- Russospira harrisae
            |        |  |  `-- Ecculiomphalus bucklandi
            |        |  `--o Helicotomidae Wenz, 1938
            |        |     |?- Linsleyella Rohr, 1980
            |        |     |-- Lophonema peccatonica Ulrich, in Purdue & Miser, 1916
            |        |     |--+-- Polehemia taneyensis
            |        |     |  `-- Walcottoma frydai
            |        |     `--+--+--o Ophiletina Ulrich & Scofield, 1897
            |        |        |  |  |-- Oriostoma bromidensis
            |        |        |  |  `--+-- O. sublaxa
            |        |        |  |     `-- O. angularis
            |        |        |  `--o Helicotoma Salter, 1859
            |        |        |     |-- H. tennesseensis
            |        |        |     |--+-- H. planulata
            |        |        |     |  `--+-- H. robinsoni
            |        |        |     |     `-- H. blodgetti
            |        |        |     `--o Palaeomphalus Koken, 1925
            |        |        |        |-- P. ?gradatus
            |        |        |        `-- Helicotoma? sp. [Girvan sp.]
            |        |        `--+--o Anomphalidae Wenz, 1938
            |        |           |  `--o Trochomphalus Koken, 1925
            |        |           |     |-- Trochomphalus ?dimidiatus
            |        |           |     `--+-- Straporillina sp. cf. S. circe (sensu Rohr, 1988)
            |        |           |        `--+-- Grantlandispira christei
            |        |           |           `--o Pycnomphalus Lindstr÷m, 1884
            |        |           |              |-- P. acutus
            |        |           |              `--+-- P. obesus
            |        |           |                 `-- Turbocheilus immaturum
            |        |           `--o Euomphalidae de Koninck, 1881
            |        |              |?- Micromphalus Knight, 1945
            |        |              |--o Boucotspira Rohr, 1980
            |        |              |  |-- B. cariniferus [Euomphalopterus cariniferus]
            |        |              |  `-- B. ?ordovicicus [Euomphalopterus ?ordovicicus]
            |        |              |--o Euomphalopterus Roemer, 1876
            |        |              |  |-- E. subcarinatus
            |        |              |  |-- E. alatus
            |        |              |  `--+-- E. togatus
            |        |              |     `--+--+-- E. praetextus
            |        |              |        |  `-- E. undulans
            |        |              |        `--o Spinicharybdis Rohr & Packard, 1982
            |        |              |           |-- S. frenatus [Euomphalopterus frenatus]
            |        |              |           `-- S. wilsoni
            |        |              |--o Poleumita Clarke & Ruedemann, 1903
            |        |              |  |-- P. alata
            |        |              |  `--+-- P. discors
            |        |              |     |-- P. granulosa
            |        |              |     |-- Centrifugus planorbis Bronn, 1834
            |        |              |     |--o Nodonema Linsley, 1968
            |        |              |     |  |-- N. rugosa [Poleumita rugosa]
            |        |              |     |  `-- N. octavia [Poleumita octavia]
            |        |              |     `--+-- Euomphalus Sowerby, 1814
            |        |              |        `-- Straparollus de Montfort, 1810
            |        |              `--o Pseudophoridae Miller, 1889
            |        |                 |?- Elasmonema Fischer, 1885
            |        |                 |-- Streptotrochus lamellosus [Boucotspira [in partim]]
            |        |                 `--+-- Streptotrochus? visbeyensis [Boucotspira [in partim]]
            |        |                    `--+--o Streptotrochus Perner, 1903
            |        |                       |  |-- S. incisus
            |        |                       |  `--+-- S. lundgreni
            |        |                       |     `-- Hystricoceras astraciformis Jahn, 1894
            |        |                       `--o Discordichilus Cossmann, 1918
            |        |                          |-- Streptotrochus sp. aff. S. incisus
            |        |                          `--+-- D. gotlandicus [Siluriphorus gotlandicus]
            |        |                             |-- D. undulans [Siluriphorus undulans]
            |        |                             |--+--+-- D. dalli
            |        |                             |  |  `-- D. mollis
            |        |                             |  `--o Pseudotectus Perner, 1903
            |        |                             |     |-- P. kolmodoni [Discordichilus kolmodoni]
            |        |                             |     `-- P. comes
            |        |                             `--o Pseudophorus Meek, 1873
            |        |                                |-- P. stuxbergi
            |        |                                `-- P. profundus
            |        `--o Lesueurillidae Wagner, 2002
            |           |-- "Lesueurilla" declivis
            |           |--o Eccyliopterus RemelÚ, 1888
            |           |  |-- E. regularis
            |           |  `--+-- E. ?princeps
            |           |     `--+-- E. alatus
            |           |        `-- E. owenanus
            |           `--+-- "Lesueurilla" prima
            |              |--o Lesueurilla Koken, 1898
            |              |  |-- "Eccyliopterus" louderbacki
            |              |  `--+-- Lesueurilla infundibula
            |              |     `-- "Eccyliopterus" beloitensis
            |              |--o Mestoronema Wagner, 2002
            |              |  |-- "Lesueurilla" marginalis
            |              |  `--+-- "Lesueurilla" scotica
            |              |     `-- "Lesueurilla" bipatellare
            |              `--o Pararaphistoma Vostokova, 1955
            |                 |-- Climacoraphistoma vaginati
            |                 |-- Climacoraphistoma damesi
            |                 `--+-- Pararaphistoma qualteriana
            |                    `-- Pararaphistoma schmidti
            `--o Asgardaspira Wagner, 2002
               |-- Barnesella measuresae
               `--+-- Lytospira yochelsoni
                  `--+--o Lytospira Koken, 1896
                     |  |-- L. angelini
                     |  `-- L. subrotunda
                     `--+--+-- Lytospira gerrula
                        |  `-- Lytospira ?norvegica
                        `--o EUOMPHALOIDEA de Koninck, 1881
                           `--o Raphistomatidae Koken, 1896
                              |-- Ceratopea canadensis 
                              |-- Orospira bigranosa Butts, 1926
                              |--o Bridgeites Flower, 1968a
                              |  |-- B. planodorsalis
                              |  `--+-- B. supraconvexa
                              |     `-- B. ?disjuncta
                              `--+-- Ceratopea ?laurentia
                                 |--+-- Ceratopea pygmaea
                                 |  `-- Ceratopea unguis 
                                 `--+-- Pararaphisoma lemoni
                                    `--+-- Helicotoma medffraensis Salter, 1859
                                       `--+--o Scalites Emmons, 1842
                                          |  |-- "Palaeomphalus" giganetus Koken, 1925
                                          |  `--+-- Scalites katoi
                                          |     `--+--+-- Raphistoma tellerensis
                                          |        |  `-- Raphistoma peracuta
                                          |        `--+-- Scalites angulatus
                                          |           `--o Raphistoma Hall, 1847
                                          |              |-- Raphistoma striata
                                          |              `-- Helicotoma gubanovi
                                          `--o Holopeidae Wenz, 1938
                                             |?- Umbospira Perner, 1903
                                             |--o Raphistomina Ulrich & Scofield, 1897
                                             |  |-- R. lapicida
                                             |  |-- R. aperta
                                             |  |-- R. fissurata
                                             |  `-- R. rugata
                                             `--+-- Pachystrophia devexa
                                                |--+-- Pachystrophia contigua
                                                |  `--o Holopea Hall, 1847
                                                |     |-- H. insignis
                                                |     |-- H. pyrene
                                                |     `--+-- H. rotunda
                                                |        `-- H. symmetrica
                                                `--+--o Sinutropis Perner, 1903
                                                   |  |-- Pachystrophia spiralis
                                                   |  |-- Sinutropis ?esthetica
                                                   |  `-- Euomphalus tubus
                                                   `--o Pachystrophia Perner, 1903
                                                      |-- P. gotlandica
                                                      `--+-- Lytospira triquestra
                                                         `-- Lytospira subuloides

Reference(s):

Wagner, P. J., 2002 [1995]: Phylogenetic relationships of the earliest anisostrophically coiled gastropods. --Smithsonian Contributions to Paleobiology: Vol. 88, pp. vi-152
[Author notes that scientific material of this article is based on his 1995 Ph.D. dissertation, which is partly outdated]


note: in keeping with the convention of the Treatise authors of the volumes on Gastropoda and Cephalopoda, the suffix -ina is used for suborders, and -ida for orders. Since the Euomphalida are here considered of ordinal rank, the previous suffix -ina has been changed accordingly



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page uploaded 5 March 2003, dendrogram uploaded 27 February 2003
checked ATW050720, dendrogram checked ATW090318
original material Creative Commons Attribution M. Alan Kazlev revised MAK120621 dendrogram © Mikko Haraamo