Non-marine mollusks on Randall's Island, NYC, and Wave Hill in the Bronx

I am hoping to increase the number of non-marine mollusk species which are known from Randall's Island. I have not done much dedicated searching yet, but I hope to do more looking, on land and in freshwater.

Here are all the elements of the fauna that are currently known. Note that so far only three of these are entirely or partly based on my records -- those three are marked like this (S).


  • Viviparus georgianus -- Banded Mysterysnail -- one shell washed up on the Wards Island beach (S) -- could perhaps be from some distance away
  • Physidae sp. -- Tadpole Snails -- in the freshwater pond within the freshwater wetlands


  • Succineidae -- amber snails -- one found near Icahn Stadium
  • Cochlicopa lubrica -- one near Central Road, and more recently one in the freshwater wetlands woodland under a log (S)
  • Discus rotundatus -- one in the Urban Farm (S), and some near Central Road (S)
  • Deroceras sp -- on the east stretch of Hell Gate Circle
  • Cepaea nemoralis -- colonies in many different places on the island (S)

Other than the wetland area, the park mostly tends to be dry, and the influence of humans is historically very strong. Nonetheless I am certain there are more species of non-marine mollusks to be discovered here.

Posted on July 08, 2017 07:53 PM by susanhewitt susanhewitt


Photos / Sounds


Banded Mystery Snail (Callinina georgiana)




June 15, 2017 12:33 PM EDT


Wow, this was a surprise!

This is the shell of a freshwater snail. The shell is eroded and damaged, but it sill has some dark periostracum on it.


Looking forward to see what you find Susan!

Posted by cedric_lee almost 7 years ago

Thanks Cedric. So far it's been hard work finding anything, but perhaps if we have a damp and warm fall here in NYC, I may be able to find some more species.

Posted by susanhewitt over 6 years ago

In October I have been finding a few more land snails and slugs.

Posted by susanhewitt over 6 years ago

And Cedric and I did great when he visited NYC and came to Randall's Island with me -- he found several great terrestrial micromollusks!

Posted by susanhewitt over 6 years ago

If only I could have stayed longer! So much potential for new records.

Posted by cedric_lee over 6 years ago

I love Randall's Island and I look forward to the spring and summer there. Cedric, if you have any suggestions for where and how I should search, let me know.

Posted by susanhewitt over 6 years ago

A more thorough search of the ornamental plantings near the bike trail where I found the micros might yield more species.

Posted by cedric_lee over 6 years ago

You really think so? Which other species might be there?

Posted by susanhewitt over 6 years ago

That's the fun part! You never know.

Posted by cedric_lee over 6 years ago

Well the nice layer of leaves that was there when you visited has not been there since, and hardly ever is there, so that might change things a bit.

But what I actually meant was, do you have any suggestions for what I should look out for?

(I hope to have a TG4 by the time spring rolls around so I could photograph any micromollusks that I find.)

Posted by susanhewitt over 6 years ago

Also, do you have any other ideas for where I should search?

Posted by susanhewitt over 6 years ago

Just naming some off the top of my head; I would be on the lookout for Vitrea spp., Lauria cylindracea, Lucilla spp., Zonitoides excavatus, Vallonia spp., Tandonia spp, Boettgerilla pallens, and Veronicella spp.

Optimal places to search would be local botanical gardens (under logs, rocks, leaf litter) and nurseries (under potted plants, bricks, wooden boards, etc).

Posted by cedric_lee over 6 years ago

Great, thanks Cedric! :)

Posted by susanhewitt over 6 years ago

Some botanical gardens cost an admission fee. However, it can be well worth it. I paid $8 for admission to the San Francisco Botanical Garden and ended up finding Boettgerilla pallens (second record in the US) and a springtail- Kalaphorura sp. (first record from the US), among many other introduced species.

Posted by cedric_lee over 6 years ago

I am currently most interested in recording what lives on Randall's island. I am not that interested in trying to find out everything that lives in NYC. We don't own a car, and Ed and I are 69 and 74 respectively, so we don't run around as much as we used to. I do have a friend who works in the NY Botanical Gardens, so I could get in there for free. I did once lead a group of students in a Bioblitz in the public areas of NYBG in 2014, but it was early fall after a long, hot, very dry, summer and it was hard work to find more than a very terrestrial few species, although we did better with the freshwater species.

In the fall of 2014 I also searched Wave Hill Gardens in the Bronx, where Ed and I are members, and on one visit the gardeners helped me search, even in the potting hoop garden and under the pots in the hothouse. Here is what I found:

2014 fall -- Wave Hill Gardens, the Bronx

Aquatic gastropods
Family Physidae
* Physa heterostropha (Say, 1817), in water feature, Elliptical Garden
In the Abrons woodland, mostly where it was most damp, which was not far south of the entrance to Wave Hill:
Terrestrial gastropods (slugs and snails)
Family Discidae

Discus rotundatus (O. F. Müller, 1774) - numerous
Family Arionidae (slugs)

* Arion subfuscus Draparnaud, 1805 - two, pale morph
* Arion hortensis (Ferussac 1819) -- one
Family Oxychilidae

* Oxychilus alliarius (Miller, 1822) -- four
Family Agriolimacidae (slugs)
* Deroceras reticulatum(O. F. Müller, 1774) -- one

Tuesday October 28th, with the Wave Hill gardeners also helping me search:
All terrestrial:
In the Hoop House -- nursery area:

Ambigolimax ?valentiana Ferussac, 1822, Limacidae, numerous,

Arion hortensis, numerous
Discus rotundatus, several
Deroceras reticulatum (dark form) one
Deroceras invadens Reise, Hutchinson, Schunack & Schlitt, 2011, Limacidae several, the "tramp slug".
Oxychilus alliarius , one
Potting Shed area:
Limax maximus Linnaeus, 1758, Fall 2013 one found in the kitchen "Great slug", "leopard slug".
In the tropical house:
Limacus flavus (Linnaeus, 1758), Limacidae, (juvenile) "yellow slug"

Ambigolimax ?valentiana

Arion hortensis
Deroceras invadens Reise, Hutchinson, Schunack & Schlitt, 2011
?Deroceras ??panormitanum (Lessona & Pollonera, 1882) sensu stricto, small uniformly black or near black slug

Allopeas gracile (Hutton, 1834), Subulinidae, "tropical tramp snail"

Hawaiia minuscula (Binney, 1840), Pristilomatidae

Outside the Conservatory:

Cochlicopa lubrica (O. F. Muller, 1774) one live, and one dead in wall near alpine house and dry garden, glossy pillar snail
In the Wild Garden:
Cepaea nemoralis (Linnaeus, 1758) in the wild garden (live) and dead in wall at dry garden

Oxychilus cellarius in the wild garden (one old shell)

Posted by susanhewitt over 6 years ago

@cedric_lee, did you get a chance to look at this list from Wave Hill?

Posted by susanhewitt over 6 years ago

Yes, Susan.

Posted by cedric_lee over 6 years ago

How did it seem to you?

Posted by susanhewitt over 6 years ago

I think most of those are usual. Personally, I would have dissected the Ambigolimax, Deroceras invadens/panormitanum, and Physa to confirm their identity otherwise I would have indicated as Ambigolimax cf. valentianus, but I think the "?" is another way to put it.

Posted by cedric_lee over 6 years ago

OK, thanks for the feedback Cedric. :)

Posted by susanhewitt over 6 years ago

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