This is the eighth resident of The Cliff that I have posted about. I haven’t been there since Thanksgiving, having taken a break from the we(s)tside last weekend, but I still have specimens to identify from that last visit. This isn’t one of those though. I thought I knew what it was as soon as I picked it up. But two guys from Carnegie Museum beg to differ with that.
T.A. Pearce and M.C. Fields wrote a paper in 2015 (you can read a summary here) describing research they did on 311 specimens of putative Ancotrema sportella and A. hybridum and found that the morphological diagnostic character which separated the two, beaded vs. non-beaded sculpturing on the last whorl, was consistent throughout both alleged species as being evident up to the end of 5 or so whorls, and absent after that. So that what has been called Ancotrema hybridum, and what I thought I’d found due to the lack of beading as it got close to the aperture, is just a more mature Ancotrema sportella with a larger shell. Poof, a whole species gone, but at least it was a merely literary extinction based on human wisdom, rather than an actual extinction caused by human ignorance.
This snail is in the same family, Haplotrematidae, as the predatory snail Haplotrema vancouverense that I posted about a few days ago. But the Beaded Lancetooth is more of an omnivore, and most of its meat diet consists of very small creatures it stumbles across, which merely supplement the fungi and vegetation upon which it predominantly feeds.
A note on directional orientation- most snails carry their shell with the umbilicus (the hole around which the whorls of the shell are formed) against the ground, making that the ventral surface. So height is measured from the ventral surface to the tip of the spire, and length/diameter/width is measured from the tip of the aperture to the trailing edge of the shell.
And another note on snails in general- These last two snails, the Haplotrema and the Ancotrema, are native snails and are not inclined to do damage in one’s garden. In fact the Haplotrema vancouverense would be of positive benefit due to its propensity for eating slugs.
Description– Medium to large snail (diameter up to 22mm, height to 10mm) with up to 6 1/3 whorls; crosshatching of radial lirae and spiral striae give it a beaded appearance, although sections grown after about the 5th whorl tend to lack the beading; yellowish green shell, with a fairly flat spire, which flares towards the aperture; aperture is wider than high, with a noticeable inwardly bent crease in the lip on the spire side (the palatal lip); umbilicus is open and roughly 1/4 of the diameter of the shell.
Similar species– Ancotrema hybridum is apparently a synonym of A. sportella; A. voyanum has a much deeper crease in the palatal lip, and only occurs on the south slope of the Siskiyous. Haplotrema vancouverense is superficially similar, but no other species have the creased palatal lip.
Habitat– Mesic conifer forests, under leaf litter, ferns, logs etc.
Range– Mostly west of the Cascades, with some populations on the east slope in BC, and disjunct populations in ne Washington and n Idaho.
Eats-Omnivorous, but mostly vegetation and fungi.
Eaten by– Anything carnivorous that can find it, including Haplotrema vancouverense, the predatory snail that I have previously profiled.
Adults active– Year around, but more so during the wet months, and predominantly underground during the hottest, driest, and sub freezing, times.
Etymology of names–Anco- is from the Greek for ‘bend, curve, valley’, and -trema is from the Greek for ‘hole,opening’. This references the crease in the palatal lip. The epithet sportella is from the Latin for ‘small basket/hamper’, and evidently refers to the beaded sculpturing’s resemblance to the texture of a woven basket.