Table 2

The 41 freshwater gastropod species confirmed from Mid-Atlantic drainages are listed in the left column below, ordered by their number of records in our database, with FWGNA incidence ranks.  The suffix "p" marks peripheral species, and asterisks* indicate species demonstrating non-apparent rarity.

Confirmed in this study
 Records
 FWGNA
 Common synonyms
Physa acuta 701 I-5 Physella heterostropha, P. integra
Menetus dilatatus 260 I-5 Micromenetus dilatatus
Ferrissia rivularis 228 I-5 F. parallela
Lymnaea humilis 197 I-5 Galba humilis, G. obrussa, G. parva, G. modicella, G. exigua, G. dalli, G. rustica
Ferrissia fragilis 162 I-5 F. walkeri
Lymnaea columella 159 I-5 Pseudosuccinea columella
Leptoxis carinata 140 I-5  -
Gyraulus parvus 121 I-5  -
Pleurocera virginica 117 I-5 Elimia virginica
Helisoma trivolvis 112 I-5 Planorbella trivolvis, P. pilsbryi
Helisoma anceps 108 I-5  -
Amnicola limosa 100 I-5  -
Campeloma decisum 90 I-5 C. rufrum, C. limosa, C. integra
Physa gyrina 79 I-5 Physella gyrina, Physella ancillaria
Lyogyrus granum 54 I-5 Amnicola grana, L. pupoideus, L. walkeri
Laevapex fuscus 36 I-5 L. diaphanus
Cipangopaludina chinensis 33 I-4 Bellamya chinensis, C. maleata
Planorbula armigera 23 I-4  -
Cipangopaludina japonica 21 I-4 Bellamya japonica
Littoridinops tenuipes 19 I-4  -
Fontigens bottimeri 17 I-3*  -
Valvata tricarinata 15 I-3p  -
Helisoma campanulatum 14 I-3p Planorbella campanulata
Lymnaea catascopium 14 I-3p Stagnicola catascopium, S. emarginata
Physa pomilia 11 I-4 Physella pomilia, Physella hendersoni
Promenetus exacuous 11 I-4  -
Lymnaea elodes 9 I-3p L. palustris, Stagnicola elodes, S. exilis, S. reflexa
Viviparus georgianus 8 I-4  -
Gyrulus deflectus 8 I-3p  -
Somatogyrus pennsylvanicus 8 I-3*  -
Bithynia tentaculata 6 I-3p  -
Fontigens nickliniana 5 I-4  -
Physa carolinae 5 I-4  -
Pomatiopsis lapidaria 5 I-3p  -
Fontigens orolibas 2 I-4*  -
Valvata bicarinata2I-4 -
Pleurocera proxima 1 I-5 Elimia proxima
Lioplax subcarinata 1 I-4  -
Potamopyrgus antipodarum 1 I-1p  -
Aplexa elongata 1 I-1p A. hypnorum
Physa vernalis 1 I-1  -
TOTAL 2,905    

    
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