Idaholanx Clark, Campbell & Lydeard

Campbell, David C., Clark, Stephanie A. & Lydeard, Charles, 2017, Phylogenetic analysis of the Lancinae (Gastropoda, Lymnaeidae) with a description of the U. S. federally endangered Banbury Springs lanx, ZooKeys 663, pp. 107-132: 111-112

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scientific name

Idaholanx Clark, Campbell & Lydeard

gen. n.

Idaholanx Clark, Campbell & Lydeard  gen. n.

Type species.

Idaholanx fresti  Clark, Campbell & Lydeard sp. n.


Shell (Figs 3, 5A). Patelliform, 2.0-3.9 mm in height and 4.0-6.7 mm in length and 3.0-5.4 mm in width. Aperture elliptical. Protoconch smooth, apex positioned posteriorly. Teleoconch sculpture of concentric growth lines. Shell pale to dark reddish brown. Internal columellar muscle scar C-shaped.

Non -genital anatomy. Columnar muscle C-shaped (Fig. 5B), gap on right side, roughly central. Digestive gland, kidney and lung typical of Lymnaeidae  and that seen for Lanx  and Fisherola  ( Baker 1925, SAC personal observations). Animal colour dark grey to black.

Genitalia anatomy (Fig. 4): The distinction between the praeputium and penial sheath is not clearly defined, the praeputium and the penial sheath are both about half the length of the penial complex. Penis is short and thick. The prostate is elongate and tube like, with the vas deferens entering apically. The uterus is strongly folded, and is surrounded by a large albumen gland. The uterus connects to the proximal part of the oviduct (oviduct I) by a short tubular duct. A roundish nidamental gland joins here. The oviduct widens into the pyriform body which is relatively large, with the anterior portion slightly more swollen than the distal portion. The short oviduct II terminates with a small vagina. The spermatheca is of moderate size and ovate. The spermathecal duct is long and widens at its opening to the vagina.


Idaholanx  , as currently recognised, is known from four isolated cold water springs (Thousand, Banbury, Briggs and Box Canyon Springs) that flow into eastern side of an 8 km section of the Snake River, in Gooding County, Idaho.


Idaholanx  gen. n. differs from Fisherola  by having a smaller, taller shell with its apex located towards the middle of the shell and not posteriorly. It differs from Lanx  by being smaller and taller and having an open C-shaped columellar muscle and not a closed circular columellar muscle (Fig. 5 C–F).


A combination of Idaho, the only state the genus is known to occur in and Lanx  , the genus it has been historically referred to and which is currently only known from northern California and southern Oregon.