Fluminicola klamathensis Liu & Hershler

Liu, Hsiu-Ping & Hershler, Robert, 2019, A new species and range extensions for three other species of pebblesnails (Lithoglyphidae, Fluminicola) from the upper Klamath basin, California-Oregon, ZooKeys 812, pp. 47-67 : 53-55

Fluminicola klamathensis Liu & Hershler sp. n. Figures 5, 6, 7, 8A

Types.

Holotype, USNM 1144499 (a cleaned shell), Lost River at Stukel Bridge, Klamath County, Oregon, 42.0825N, 121.6617W, 10/5/1997, Terrence J. Frest and Edward J. Johannes. Paratypes, USNM 1468970 (a large series of dry shells and alcohol-preserved specimens), from same lot.

Referred material.

OREGON. Klamath County: USNM 1207966, Lost River at Stukel Bridge, USNM 1144894, USNM 1469075, USNM 1469082, USNM 1469090, Wood River, south spring source (42.7372N, 121.9775W), USNM 1469072, USNM 1469077, USNM 1469078, USNM 1469080, Tecumseh Spring (42.6424N, 121.9432W), USNM 1144346, USNM 1190088, Camporee Spring (42.4308N, 122.0614W), USNM 883517, USNM 1144348, USNM 1190089, USNM 1207965, USNM 1225874, Harriman Spring, outflow of main spring (42.4673N, 122.1009W), USNM 1469076, USNM 1469086, Big Springs at Bonanza (42.1982N, 121.4004W), USNM 1469074, USNM 1469088, Lost River, below Harpold Dam (42.1702N, 121.4530W).

Diagnosis.

A large Fluminicola (shell height, 6.5-8.4 mm) with a subglobose to ovate-conic shell often having an eroded spire. Fluminicola klamathensis is readily distinguished by its penis, which does not gently taper along its length as in other congeners, but instead abruptly narrows distally and has a well demarcated, short filament. This new species is further differentiated from closely similar and frequently sympatric F. modoci in its generally darker colored shell periostracum, broad central cusps on the central and lateral radula teeth, very short outer wing of the lateral teeth, small number of cusps on the inner and outer marginal teeth, light pigment on the dorsal surface of the penis, large core of internal dark pigment in the distal section of the penis, and the fairly large seminal receptacle.

Description.

Shell (Fig. 5 A–F) subglobose to ovate-conic, spire often eroded in large part, whorls (in specimens having a complete spire), 4.25-4.5. Teleoconch whorls low to medium convex, sometimes weakly shouldered. Aperture pyriform; inner lip complete, variably thickened, broadly adnate to parietal wall; columellar shelf narrow or extending over much of umbilical region. Outer lip thin, prosocline. Umbilicus absent or a narrow slit, umbilical region sometimes excavated. Shell white, periostracum brown, fairly thick, sometimes covered with black deposits. Shell measurements and whorl count data are summarized in Table 2.

Operculum (Fig. 6 A–C) as for genus; muscle attachment margin little thickened on inner side; rim sometimes present on inner side near outer edge (Fig. 6B). Radula (Fig. 6 D–H) as for genus; dorsal edge of central teeth concave, lateral cusps 2-5, hoe-shaped; basal cusp 1-5. Lateral teeth having 2-4 cusps on inner side and 3-5 cusps on outer side; outer wing slightly longer than length of cutting edge. Inner marginal teeth with 11-19 cusps, outer marginal teeth with 11-22 cusps. Radula data are from USNM 144346, USNM 1468970.

Snout, cephalic tentacles grey or black, pigment light around eyespots; pallial roof, visceral coil usually light brown; foot variably pigmented dorsally, sole pale. Ctenidial filaments 33-36 (N = 5), broadly triangular. Glandular oviduct and associated structures shown in Figure 7A, B. Coiled oviduct circular, anterior arm kinked, posterior arm sometimes having small accessory pouches containing sperm. Bursa copulatrix large, ovate or globular, partly overlapped by albumen gland. Bursal duct narrow, much shorter than bursa. Seminal receptacle medium-sized, pouch-like, partly overlapped by albumen gland. Albumen gland having small pallial component. Capsule gland slightly shorter than albumen gland. Genital aperture a small, terminal pore. Penis (Figs 7C, D, 8A) large, base rectangular, often having a distinct, lobe-like swelling along inner edge distally (Fig. 7D); distal end of penis blunt, with short, narrow, filament. Distal section of penis having dense core of internal black pigment; dorsal surface pale or lightly pigmented. Penial duct near inner edge, narrow, nearly straight.

Etymology.

The species name is an adjectival geographic epithet referring to the distribution of this pebblesnail in the (upper) Klamath River basin.

Distribution.

Large, spring-influenced habitats in the UKL.

Remarks.

We selected the Lost River at Stukel Bridge as the type locality because the pebblesnails in this population do not have apically eroded shells. However, we did not have suitably relaxed material from this locality for anatomical study and thus used specimens from Harriman Springs for this purpose.

The shells of F. klamathensis and F. modoci can be difficult to distinguish although the former usually has darker, thicker periostracum, and tends to be larger when found in sympatry. As noted above, these two species are most readily differentiated by the shape and pigmentation of the penis (Fig. 8).

Sixteen (16) COI and 13 cytB haplotypes were detected in F. klamathensis (Suppl. materials 2, 3, respectively).

The "Tall pebblesnail" (also referred to as Fluminicola n. sp. 2) that was recognized by Frest and Johannes in their UKL contract reports (also see Frest and Johannes 1999) and subsequently included in the Northwest Forest Plan as a Survey and Manage species, corresponds to F. klamathensis .