Rhytidoidea

Dorcasia alexandri, copyright H. Zell.

Belongs within: Heterobranchia.
Contains: Pedinogyra, Rhytida, Paryphanta.

The Rhytidoidea are a group of snails united by molecular phylogenetic analysis, many of which are carnivorous. Members of the clade vary from small to gigantic in size with the giant panda snail Hedleyella falconeri of eastern Australia growing up to 90 mm in diameter. The Rhytididae of southern Africa and Australasia are carnivorous and bear lightweight, shiny, subglobose to discoidal shells with a sculpture of radial ribs and/or spiral striae and wrinkles. The Caryodidae of eastern Australia are large herbivorous snails with shells varying from elongately conical to discoidal or ear-shaped (Stanisic et al. 2010).

The Australian panda
Published 2 December 2018

The world is home to an incredible diversity of snails: there are literally thousands of species, some widespread, some restricted to very small areas. Most, as is the usual way of things, are tiny, barely discernible without very close examination. But then there are some that are very much not—such as the giant panda snail Hedleyella falconeri.

Giant panda snail Hedleyella falconeri, from the Queensland Museum.

Giant pandas are found on rainforest floors in northern New South Wales and southern Queensland, in a range spanning from the Barrington Tops to the D’Aguilar Range. They are Australia’s largest land snail, reaching nine centimetres in diameter, about the size of a tennis ball. They have globose, reddish brown shells with a spiral pattern of darker broken bands. Their name bears no relation to any Asian mammals; instead, they were gifted the genus name Panda as a derivation from the Latin word pandere, meaning to stretch out or extend, presumably in reference to their size. The genus name later had to be changed but it survives in the vernacular (as well as in the name of a closely related genus of slightly smaller snails, Pygmipanda).

Panda snails are nocturnal, spending the days in moist spots such as buried in leaf litter or hidden under logs. At night, they roam in search of fallen leaves and fungal fruiting bodies. A study of giant pandas that tracked individual snails found that they wandered more or less randomly, up to about 20 metres over the course of a night, without returning to any particular ‘home’ site.

A demonstration of the size of H. falconeri, from Pollinator Link.

Like many other land snails, giant pandas are hermaphrodites, able to both fertilise and be fertilised during mating. They may have the largest sperm cells of any mollusc, each over a millimetre in length. Mating usually happens on a February night though observations in captivity suggest it may happen whenever consitions are suitable. The snail lays its hard-shelled eggs in batches of fifteen to twenty in a burrow in the leaf litter*. To continue with the theme, these are also realtively gigantic: close to two centimetres in diameter, comparable in size to those of a small bird. The young snails hatch at about 15 mm in size (I haven’t found any reference to the eggs being tended by the parent in any way) and grow slowly. By the time they reach a year in age, they may not have even doubled in size, and it presumably takes several years for them to reach their full extent.

*So it turns out Paazan was right after all: pandas do hatch from eggs.

Pandas are not uncommon within their range and are not generally regarded as a conservation concern. Indeed, their nomadic habits have led to the suggestion that they may be well disposed to re-colonising regenerating forest (Parkyn & Newell 2013). Nevertheless, recent years have seen increasing fragmentation of suitable habitat within their range and this, together with their slow growth rate, means that I can easily imagine them becoming vulnerable if conditions deteriorate. I would hope that appropriate action is taken to ensure that there should always be giant pandas in eastern Australia.

Systematics of Rhytidoidea
<==Rhytidoidea [Acavacea, Acavoidea, Rhytidacea, Rhytidoidei, Rhytidoinei, Strophocheilacea, Strophocheiloidea]
    |--Clavator Martens 1860BR05 [ClavatoridaeBR17, Clavatorinae]
    |    `--*C. clavator (Petit de la Saussaye 1844) [=Bulimus clavator]BR17
    |--Strophocheilus Spix 1827 (see below for synonymy)BR05
    |    |--*S. almeida Spix 1827BR17
    |    |--S. avus Parodiz 1949P63
    |    |--S. chubutiensis Ihering 1904P63
    |    `--S. hauthali Ihering 1904P63
    |--Megalobulimus Miller 1878BR05 [MegalobulimidaeS11, Megalobuliminae]
    |    |--*M. garciamoreni (Miller 1878) [=Bulimus garciamoreni]BR17
    |    |--M. mogianensis Simone & Leme 1998S11
    |    `--M. riopretensis Simone & Leme 1998S11
    |--Macrocyclis Beck 1837 [Macrocyclidae]BR05
    |    |--*M. peruvianus (Lamarck 1822) [=Helix peruviana]BR17
    |    |--M. concavaW79
    |    |--M. covani (Smith 1879) [=Helix (Macrocyclis) covani]S79
    |    |--M. newberryanaC64
    |    |--M. sportella [=Helix (Patula) sportella, Iberus (Campylaea) sportella]C64
    |    `--M. vancouverensis (see below for synonymy)C64
    |--Dorcasiidae [Dorcasieae, Dorcasiinae]BR05
    |    |--TrigonephrusPB27
    |    |--TulbaghiniaPB27
    |    `--Dorcasia Gray 1838BR05
    |         |--*D. alexandri Gray 1838BR17
    |         |--D. antiqua Wenz 1926TTE93
    |         |--D. bolus (Benson 1863) [=Helix (Dorcasia) bolus]TC89
    |         |--D. extrusa (Tapparone Canefri 1889) [=Helix (Dorcasia) extrusa]TC89
    |         `--D. scalpturita (Benson 1859) [=Helix (Dorcasia) scalpturita]TC89
    |--AcavidaeBR17
    |    |--Ampelita Beck 1837TTE93
    |    |    `--A. shavi (Smith 1879) [=Helix (Ampelita) shavi]S79
    |    |--Helicophanta Férussac 1821TTE93
    |    |    `--H. brevipes [=Helix brevipes]G40
    |    |--Leucotaenius Martens 1860BR17
    |    |    `--L. favannii (Lamarck 1822) [=Bulimus favannii, Liparus favennii]BR17
    |    `--Acavus Montfort 1810 [Acavinae, Macroogona, Macroon]BR05
    |         |--*A. haemastoma (Linnaeus 1758) [=Helix haemastoma]BR17
    |         `--A. hybridusG40 [=Helix (Acavus) hybridaG40, H. nemoralis var. hybridaA79]
    |--Megomphicidae [Ammonitellidae, Megomphicinae]BR05
    |    |--Megomphix Baker 1930BR05
    |    |    `--*M. hemphilli (Binney 1879) [=Macrocyclis hemphilli]BR17
    |    |--Ammonitella Cooper 1869 [Ammonitellinae]BR05
    |    |    `--*A. yatesii Cooper 1869BR17
    |    |--Glyptostoma Bland & Binney 1873BP90
    |    |    `--G. newberryanumBP90
    |    |--Polygyroidea Pilsbry 1930BP90
    |    |    `--P. harfordianaBP90
    |    `--Polygyrella Bland 1869 [Polygyrellinae]BR05
    |         |--*P. polygyrella (Bland & Cooper 1861)BR17 [=Helix polygyrellaBR17, H. (Polygyra) polygyrellaC64]
    |         `--P. lunata (Conrad 1870)TTE93
    |--CaryodidaeSS10
    |    |--PedinogyraSS10
    |    |--Caryodes Albers 1850 [Caryodinae]BR05
    |    |    `--*C. dufresnii (Leach 1815) [=Bulimus dufresnii]BR17
    |    |--Anoglypta Martens 1860 [Anoglyptidae]BR05
    |    |    `--*A. launcestonensis (Reeve 1852) [=Helix launcestonensis]BR17
    |    |--Brazieresta Iredale 1933SS10
    |    |    `--*B. larreyi (Brazier 1871) [=Bulimus larreyi]SS10
    |    |--Pandofella Iredale 1933SS10
    |    |    `--*P. whitei (Hedley 1912) [=Panda whitei]SS10
    |    |--Hedleyella Iredale 1914BR05 [=Panda Martens 1860BR17; Hedleyellidae, Hedleyelloidea]
    |    |    |--*H. falconeri (Gray 1834)SS10 (see below for synonymy)
    |    |    `--H. maconelli (Reeve 1853)SS10
    |    `--Pygmipanda Iredale 1933SS10 [incl. Liparus Albers 1850 non Olivier 1807BR17]
    |         |--*P. atomata (Gray 1834) SS10 (see below for synonymy)SS10
    |         `--P. kershawi (Brazier 1872) [incl. P. kershawi divulsa Iredale 1937]SS10
    `--Rhytididae [Paryphantacea, Paryphantidae]SS10
         |  i. s.: Ouagapia inaequalis (Pfeiffer 1854)TMT96
         |         Limesta Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--*L. sheridani (Brazier 1875) [=Helix (Rhytida) sheridani]SS10
         |         Microdelos Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--*M. pallida Stanisic in Stanisic, Shea et al. 2010SS10
         |         Costadelos Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--*C. dryander Stanisic in Stanisic, Shea et al. 2010SS10
         |         Altidelos Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--*A. bellendenker Stanisic in Stanisic, Shea et al. 2010SS10
         |         Minidelos Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--*M. mossman Stanisic in Stanisic, Shea et al. 2010SS10
         |         Torresiropa Iredale 1933SS10
         |           `--*T. spaldingi (Brazier 1876) (see below for synonymy)SS10
         |         Murphitella Iredale 1933SS10
         |           |--*M. franklandiensis (Forbes 1851) (see below for synonymy)SS10
         |           `--M. froggatti Iredale 1933SS10
         |         Protorugosa Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |           |--*P. burraga Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |           `--P. alpica (Iredale 1943) [=Strangesta alpica]SS10
         |         Terrycarlessia Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--*T. turbinata Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--T. bullacea (Reeve 1854)SS10 [=Strangesta bullaceaSC07]
         |         Prolesophanta Iredale 1933SS10
         |           |--*P. dyeri (Petterd 1879) [=Helix dyeri]SS10
         |           `--P. occlusa Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |         Laevidelos Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--*L. moria Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--L. clermont Stanisic in Stanisic, Shea et al. 2010SS10
         |         Saladelos Iredela 1933SS10
         |           |--S. commixta Iredale 1933 [=Helix splendidula Pfeiffer 1846, *S. splendidula]SS10
         |           |--S. lacertina Iredale 1933 [=S. commixta lacertina]SS10
         |           `--S. macquariensisSC07
         |         Griffithsina Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--*G. connorsiana Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--G. brisbanica Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--G. subglobosa Stanisic in Stanisic, Shea et al. 2010SS10
         |         Briansmithia Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--*B. ptychomphala (Reeve 1852) [=Helix ptychomphala]SS10
         |           |--B. clarkensis Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--B. jackstirlingi Stanisic in Stanisic, Shea et al. 2010SS10
         |         Pseudechotrida Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--*P. bordaensis Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--P. bouldercombe Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--P. mikros Stanisic in Stanisic, Shea et al. 2010SS10
         |         Macrodelos Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--*M. bensa (Iredale 1933) [=Saladelos commixta bensa]SS10
         |           |--M. bishopi Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--M. hobsoni (Brazier 1876)SS10
         |         Umbilidelos Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--*U. manierorum Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--U. altonmoui Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--U. mcilwraith Stanisic in Stanisic, Shea et al. 2010SS10
         |         Echotrida Iredale 1933SS10
         |           |--*E. strangeoides (Cox 1864) [=Helix strangeoides]SS10
         |           |--E. globosa Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--E. substrangeoides Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--E. tropica Stanisic in Stanisic, Shea et al. 2010SS10
         |         Strangesta Iredale 1933SS10
         |           |--S. capillaceaK64
         |           |--S. confusa (Pfeiffer 1855) [incl. Helix leichardti Cox 1864, *S. leichardti]SS10
         |           |--S. assimilansSC07
         |           |--S. maxima (Mousson 1869) [=Zonites strangei maxima]SS10
         |           `--S. ramsayi (Cox 1868) [=Helix ramsayi]SS10
         |         Annabellia Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |           |--*A. bingara Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |           |--A. assimilans (Cox 1864) [=Helix assimilans]SS10
         |           |--A. occidentalis Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |           `--A. subglobosa Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |         Montidelos Iredale 1943SS10
         |           |--*M. orcadis Iredale 1943SS10
         |           |--M. canerisi Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--M. exiguus Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |           |--M. macquariensis (Cox 1872) [=Helix macquariensis]SS10
         |           `--M. urarensis (Cox 1866)SS10 [=Saladelos urarensisSC07]
         |         Vitellidelos Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--*V. dulcis (Iredale 1943) [=Saladelos dulcis]SS10
         |           |--V. costata Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--V. dorrigoensis Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |           |--V. helmsiana (Iredale 1938)SS10
         |           `--V. kaputarensis Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |         Delos Hutton 1904P61
         |           |--D. (Delos)P61
         |           |    |--*D. (D.) coresia (Gray 1850) [=Zonites coresia]P61
         |           |    `--D. (D.) jeffreysiana (Pfeiffer 1853)P61
         |           `--D. (Delouagapia Powell 1952)P61
         |                `--D. (*D.) cordelia (Hutton 1883) [=Gerontia cordelia]P61
         |         Austrorhytida Smith 1987SS10
         |           |--*A. capillacea (Férussac 1832) (see below for synonymy)SS10
         |           |--A. barringtoniana Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |           |--A. glaciamans (Iredale 1938) [=Strangesta glaciamans]SS10
         |           |--A. harriettae (Cox 1868) [=Helix harriettae]SS10
         |           |--A. nandewarensis Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |           `--A. warrumbunglensis Shea & Griffiths in Stanisic, Shea et al. 2010SS10
         |         Wainuia Powell 1930P61
         |           |--*W. urnula (Pfeiffer 1855) [=Helix urnula]P61
         |           |    |--W. u. urnulaP61
         |           |    `--W. u. nasuta Powell 1946P61
         |           |--W. clarki Powell 1936P61
         |           |--W. edwardi (Suter 1899)P61
         |           `--W. fallai Powell 1946P61
         |         Schizoglossa Hedley 1902P61
         |           |--*S. novoseelandica (Pfeiffer 1862)P61 [=Daudebardia novoseelandicaP61, D. neozelanicusC01]
         |           |    |--S. n. novoseelandicaP61
         |           |    `--S. n. barrierensis Powell 1949P61
         |           |--S. gigantea Powell 1930P61
         |           |--S. major Powell 1938P61
         |           `--S. worthyae Powell 1949P61
         |         Scagacola Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--*S. cavernula Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--S. brigalow Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--S. degenerata Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--S. eddiei Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--S. einasleigh Stanisic in Stanisic, Shea et al. 2010SS10
         |           |--S. reducta Stanisic in Stanisic, Shea et al. 2010SS10
         |           `--S. subcavernula Stanisic in Stanisic, Shea et al. 2010SS10
         |--Chlamydephorus Binney 1879BR05 [=Apera Heynemann 1885BR05; Aperidae, Chlamydephoridae, ChlamydephorinaeBR17]
         |    `--*C. gibbonsi Binney 1879 [=*Apera gibbonsi]BR17
         `--RhytidinaeBR17
              |--RhytidaBR05
              |--ParyphantaBR17
              `--Occirhenea Iredale 1933BR17, BR05 [Occirheneidae]
                   `--*O. georgiana (Quoy & Gaimard 1832) [=Helix georgiana]BR17

*Austrorhytida capillacea (Férussac 1832) [=Helix capillacea; incl. Nanina fricta Gould 1852, Strangesta sanguinolenta McLauchlan 1954, Helix strangei Pfeiffer 1849]SS10

*Hedleyella falconeri (Gray 1834)SS10 [=Helicophanta falconeriSS10, *Panda falconeriBR17; incl. P. falconeri azonata Hedley 1892 non P. atomata azonata Hedley 1892SS01, Hedleyella falconeri imitator Iredale 1933SS10, Helix infundubulum Valenciennes 1846SS10, Hed. falconeri jacksoniana Iredale 1933SS10, Panda falconeri tigris Hedley 1892SS10]

Macrocyclis vancouverensis [=Discus vancouverensis, Helix vancouverensis; incl. H. concava, H. vellicata, Macrocyclis vellicata]C64

*Murphitella franklandiensis (Forbes 1851) [=Helix franklandiensis; incl. H. (Rhytida) beddomei Brazier 1876, H. (R.) jamesi Brazier 1876]SS10

*Pygmipanda atomata (Gray 1834)SS10 [=Bulimus atomatusSS10, Liparus atomatusBR17; incl. Panda atomata azonata Hedley 1892SS10, P. atomata elongata Hedley 1892SS10]

Strophocheilus Spix 1827 [=Strophochilus Agassiz 1846; Strophocheileae, Strophocheilidae, Strophocheilinae, Strophochilinae]BR05

*Torresiropa spaldingi (Brazier 1876) [=Helix (Patula) spaldingi; incl. H. (P.) spaldingi carinata Brazier 1880 nec H. carinata Müller 1774 nec H. carinatus Sowerby 1812, Torresiropa mella Iredale 1933]SS10

*Type species of generic name indicated

References

[A79] Ashford, C. 1879. Land and freshwater shells observed in the neighborhood of Redcar. Journal of Conchology 2: 236–241.

[BR05] Bouchet, P., & J.-P. Rocroi. 2005. Classification and nomenclator of gastropod families. Malacologia 47 (1–2): 1–397.

[BR17] Bouchet, P., J.-P. Rocroi, B. Hausdorf, A. Kaim, Y. Kano, A. Nützel, P. Parkhaev, M. Schrödl & E. E. Strong. 2017. Revised classification, nomenclator and typification of gastropod and monoplacophoran families. Malacologia 61 (1–2): 1–526.

[BP90] Burch, J. B., & T. A. Pearce. 1990. Terrestrial Gastropoda. In: Dindal, D. L. (ed.) Soil Biology Guide pp. 201–309. John Wiley & Sones: New York.

[C64] Carpenter, P. P. 1864. Supplementary report on the present state of our knowledge with regard to the Mollusca of the west coast of North America. Report of the British Association for the Advancement of Science 33: 517–686.

[C01] Collinge, W. E. 1901. On the anatomy of certain agnathous pulmonate mollusks. Annals and Magazine of Natural History, series 7, 7: 65–73.

[G40] Gray, J. E. 1840. A Manual of the Land and Fresh-water Shells of the British Islands, with figures of each of the kinds. By William Turton, M.D. A new edition, thoroughly revised and much enlarged. Longman, Orme, Brown, Green, and Longmans: London.

[K64] Krauss, N. L. H. 1964. Investigations on biological control of giant African (Achatina fulica) and other land snails. Nautilus 78 (1): 21–27.

Parkyn, J., & D. A. Newell. 2013. Australian land snails: a review of ecological research and conservation approaches. Molluscan Research 33 (2): 116–129.

[P63] Parodiz, J. J. 1963. New fresh-water Mollusca from the Eogene of Chile and Patagonia. Nautilus 76 (4): 145–148.

[PB27] Pilsbry, H. A., & J. Bequaert. 1927. The aquatic mollusks of the Belgian Congo, with a geographical and ecological account of Congo malacology. Bulletin of the American Museum of Natural History 53 (2): 69–602, pls 10–77.

[P61] Powell, A. W. B. 1961. Shells of New Zealand: An illustrated handbook 4th ed. Whitcombe and Tombs Limited: Christchurch.

[S11] Simone, L. R. L. 2011. Phylogeny of the Caenogastropoda (Mollusca), based on comparative morphology. Arquivos de Zoologia 42 (4): 161–323.

[S79] Smith, E. A. 1879. Descriptions to two species of Helicidae from Madagascar. Journal of Conchology 2: 337–339.

[SC07] Stanisic, J., R. A. D. Cameron, B. M. Pokryszko & J. C. Nekola. 2007. Forest snail faunas from S. E. Queensland and N. E. New South Wales (Australia): patterns of local and regional richness and differentiation. Malacologia 49 (2): 445-462.

[SS10] Stanisic, J., M. Shea, D. Potter & O. Griffiths. 2010. Australian Land Snails vol. 1. A. field guide to eastern Australian species. Bioculture Press: Mauritius.

[TC89] Tapparone Canefri, T. 1889. Viaggio di Leonardo Fea in Birmania e regioni vicine. XVIII.—Molluschi terrestri e d’acqua dolce. Annali del Museo Civico di Storia Naturale di Genova, Serie 2a, 7: 295–359.

[TMT96] Tillier, S., M. Masselot & A. Tillier. 1996. Phylogenetic relationships of the pulmonate gastropods from rRNA sequences, and tempo and age of the stylommatophoran radiation. In: Taylor, J. D. (ed.) Origin and Evolutionary Radiation of the Mollusca pp. 267–284. Oxford University Press: Oxford.

[TTE93] Tracey, S., J. A. Todd & D. H. Erwin. 1993. Mollusca: Gastropoda. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 131–167. Chapman & Hall: London.

[W79] Walker, B. 1879. Catalogue of the shell-bearing Mollusca of Michigan. Journal of Conchology 2: 325–337.

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