drought mussels from the South Nation drainage

[Fred Schueler]

Everyone,

During last September's drought, Naomi Langlois picked up some Unionid
shells as she was doing various surveys, and it has taken this long to
transfer the shells (interruptions by delicious road-killed Deer, etc.)
and me to look at them.

The most striking specimen is an Alasmidonta undulata from South Indian
Creek, one of a very few of this species that I've found in the South
Nation.

The sample from Bear Brook/Robillard Road confirms the diversity at this
site -
https://karstaddailypaintings.blogspot.com/2011/10/bear-brook-haven-of-diversity-oil-on.html
- and the some of the Lasmigona costata with their ribs reduced to wrinkles.

fred.
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24 September 2025: Canada: Ontario: Stormont, Dundas & Glengarry Cos:
Mountain: Inkerman, N. Branch South Nation River at bridge, 45.03449° N
75.39528° W HABITAT: drought-dry bedrock/cobble/broken limestone stream
in rural village. OBSERVER: Naomi Langlois. NL-A25Sep24/a, Elliptio
complanata (Eastern Elliptio) (Mollusca). 2 shell, specimen. 87 mm, 76.5
mm fairly fresh pairs.

(same location) NL-A25Sep24/b, Lampsilis radiata (Eastern Lamp-Mussel)
(Mollusca). 1 shell, specimen. not-fresh 72 mm pair.

moved 7.24km SW - South Nation R/County Road 1, South Mountain,
44.98604° N 75.45681° W HABITAT: clear/brownwater rocky/Butomus river,
brushy/oldfield banks, agricultural/settled. NL-A25Sep24/c, Lampsilis
cardium (Mollusca). 2 shell, specimen. not-fresh 101 mm & 108 mm F valves.

(same location) NL-A25Sep24/d, Elliptio complanata (Eastern Elliptio)
(Mollusca). 1 shell, specimen. not-fresh 69.5 mm valve.

26 September 2025 - moved 57.6km NNE - Canada: Ontario: Prescott &
Russell County: Bear Brook/Robillard Road, 1 km SSE Ettyville. (100m
site), 45.43361° N 75.08432° W HABITAT: incised meandering
clay/sand/cobble creek with treed banks among agricultural fields.
OBSERVER: Naomi Langlois. NL-A25Sep26/a, Ligumia recta (Black
Sand-Shell) (Mollusca). 2 shell, specimen. fresh pairs, 126 mm & 125
mm(w dried flesh).

(same location) NL-A25Sep26/b, Potamilus alatus (Pink Heelsplitter)
(Mollusca). 1 shell, specimen. algaed-over fairly fresh pair, only a
hint of pink nacre.

(same location) NL-A25Sep26/c, Lampsilis cardium (Mollusca). 6 shell,
specimen. all pairs, fresh to old.

NUMBER/SEX/SIZE
1)m, 122
2)f, 111
3)f, 100
4)m, 103
5)m, 100
6)f, 87, the freshest shell

(same location) NL-A25Sep26/d, Elliptio complanata (Eastern Elliptio)
(Mollusca). 11 shell, specimen. 5 pairs, 6 valves, fresh to old heavy
shells, largest 100.5 mm, smallest 74 mm.

(same location) NL-A25Sep26/e, Lasmigona costata (Fluted Shell)
(Mollusca). 18 shell, specimen. 7 pairs, 11 valves, fresh to
not-very-fresh. Obscure or fine ribbing - largest 118 mm, smallest 68 mm.

moved 13.9km WSW - South Indian Creek/South Indian Creek Road. (100m
site), 45.38954° N 75.25041° W - NL-A25Sep29/a, Lampsilis cardium
(Mollusca). 1 shell, specimen. broken old 117.5 mm pair.

(same location) NL-A25Sep29/b, Elliptio complanata (Eastern Elliptio)
(Mollusca). 1 shell, specimen. old 99 mm pair.

(same location) NL-A25Sep29/c, Pyganodon grandis (Common Floater)
(Mollusca). 1 shell, specimen. fresh bkoen 70.5 mm pair, wrinkly beak
sculpture.

(same location) NL-A25Sep29/d, Alasmidonta undulata (Heavy-toothed Wedge
Mussel) (Mollusca). 1 shell, specimen. fresh bkoen 56.5 mm pair with
blackish periostracum.

--
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Frederick W. Schueler & Aleta Karstad
Fragile Inheritance Natural History - https://fragileinheritance.ca/
2024 annual letter: https://clt1233162.bmeurl.co/11E63979
6 St-Lawrence Street Bishops Mills, RR#2 Oxford Station, Ontario K0G 1T0
on the Smiths Falls Limestone Plain 44.87156° N 75.70095° W
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