Juga douglasi, Strong & Garner & Johnson & Whelan, 2022

Strong, Ellen E., Garner, Jeffrey T., Johnson, Paul D. & Whelan, Nathan V., 2022, A systematic revision of the genus Juga from fresh waters of the Pacific Northwest, USA (Cerithioidea, Semisulcospiridae), European Journal of Taxonomy 848, pp. 1-97 : 50-55

Juga douglasi sp. nov.

urn:lsid:zoobank.org:act:8EA208D9-9CE9-4521-8381-7411439C8E1F

Figs 17–18

Juga (Oreobasis) nigrina – Frest & Johannes 1995b: 38 (in part).

Juga (Oreobasis) “ nigrina ” – Frest & Johannes 1995b: 39 (in part).

Juga interioris – Lee et al. 2006: 316. — Ó Foighil et al. 2009: 305.

Juga n. spp. – Frest & Johannes 2007: table 4.

Juga (Oreobasis) OTU 2 – Campbell et al. 2016: 160.

Juga (Oreobasis) OTU 3 – Campbell et al. 2016: 160.

Juga species 1 – Strong & Whelan 2019: 89, fig. 4g –l.

Etymology

Named in honor of the father of the first author, Douglas Wayne Strong. A native Californian, Doug shared with his family his deep appreciation for the natural beauty of northern California, and always enjoyed hearing about the snails that also make their home amongst the majestic redwoods.

Type material

Holotype USA • 1 spm (L = 15.74 mm); California, Shasta County, Goose Valley Spring; 40.9295, -121.726; 11 Sep. 2015; E.E. Strong and P. Bouchet leg.; GenBank: MK472138 , MK464510 , MK480745 ; USNM 1413130 .

Other material examined 64 lots, 818 specimens, of which 19 were sequenced.

USA – California • 13 spms; Alameda Co., Strawberry Creek, Berkeley ; [37.871, -122.2635]; 18 Aug. 1926; E. Caruthers leg.; ANSP 145847 • 1 spm; Butte Co., Paradise ; [39.7522, -121.6143]; J. Rowell leg.; ANSP 105056 • 51 spms; Butte Co., spring on Chico Creek [possibly Richardson Springs] tributary of Sacramento River ; [39.8395, -121.7798]; Henshaw leg.; USNM 128206 • 5 spms; Butte Co., Table Mountain ; [39.5831, -121.6192]; W.M. Gabb leg.; ANSP 27568 • 6 spms; same collection data as for preceding; USNM 119284 • 9 spms; El Dorado Co., small stream 24.5 mi E of Placerville ; [38.7737, -120.3949]; 10 May 1946; M.L. Walton leg.; ANSP 346017 • 9 spms; Lassen Co., Bob Creek, at crossing of Little Valley Rd (CR 404), Beaver Creek Ranch , 5.5 mi NW of Little Valley; 40.9467, -121.2534; 1 Sep. 2007; T. Grace leg.; USNM 1111865 • 20 spms; Lassen Co., Lassen Natl Forest, Davis Spring , upstream ca 1.5 mi from FS 22 crossing, ca 19 air mi WNW of Spalding; [40.8233, -121.1026]; 15 Jun. 2001; USFS Lassen Natl Forest Mollusk Survey 2001; CASIZ 165974 • 27 spms; Nevada Co., 1 mi NW of North San Juan, small stream between South and North Forks of the Yuba River on Hwy 49 [= Clear Creek]; [39.3792, -121.091]; Jun. 1971; D.D. Chivers leg.; CASIZ 30310 • 8 spms; Nevada Co., Tahoe National Forest, East Fork Creek , 1 mi S of Washington [sic, possibly East Fork Washington Creek]; 22 Aug. 1997; J. Vindum and C. Spencer leg.; CASIZ 113099 • 2 spms; Nevada Co., Tahoe Natl Forest, Sfork of Yuba River , E of Washington along Maybert Rd , Golden Quartz picnic area; [39.356, -120.7466]; 28 Aug. 1997; E.J. Kools leg.; on rocks; CASIZ 113100 • 30 spms; Nevada Co., Tahoe Natl Forest, Washington Creek , 1 mi S of Washington; 39.3446, -120.7948; 28 Aug. 1997; E.J. Kools leg.; CASIZ 112152 • 3 spms; Placer / El Dorado Counties, Middle Fork American River ; H. Moores leg.; USNM 118854 • 20 spms; Plumas Co., Butterfly Creek, near Keddie ; [40.0071, -120.9624]; Chace and H.N. Lowe leg.; ANSP 212242 • 24 spms; Plumas Co., Domingo Springs, off CR Route 311 (approx. 7 air mi NW of Chester); [40.3609, -121.3473]; 19 Jun. 2001; USFS Lassen Natl Forest Mollusk Survey 2001; J. Brim Box leg.; CASIZ 165953 • 10 spms; Plumas Co., East Fork of Feather River [ East Branch North Fork ]; [40.0193, -121.1048]; 1898; R.C. McGregor leg.; ANSP 73510 • 5 spms; Plumas Co., Howells [possibly Howells Bridge, along East Branch North Fork Feather River, Belden]; [40.0142, -121.2258]; 29 Aug. 1946; H.P. Chandler leg.; CASIZ 170000 • 8 spms; Plumas Co., Indian Valley ; [40.1186, -120.8791]; USNM 58981 • 68 spms; Plumas Co., Lassen Natl Forest, Soldier Creek , off FS Rd 28N36, ca 7 air mi SSW of Chester; [40.2123, -121.2717]; 25 Jun. 2001; USFS Lassen Natl Forest Mollusk Survey 2001; J. Brim Box leg.; CASIZ 165371 • 3 spms; Sacramento Co., spring on Placerville Rd , ca 23 mi E of Placerville; [38.774, -120.4271]; 1916; H.N. Lowe leg.; ANSP 114784 • 14 spms; Shasta Co., Battle Creek 10 mi above mouth, tributary to Sacramento River ; [40.4147, -122.0988]; 1898; R.C. McGregor leg.; ANSP 73522 • 30 spms; Shasta Co., Blackberry Creek, Shasta NF, N side of FS50, 5.87 km E of Pit 5 Dam ; 40.9669, -121.8284; 16 Sep. 2007; T. Grace leg.; UF 520318 • 23 spms; Shasta Co., Goose Valley Spring ; 40.9295, -121.726; 11 Sep. 2015; E.E. Strong and P. Bouchet leg.; USNM 1413139 • 1 spm; same collection data as for preceding; GenBank : MK472137 , MK464509 ; USNM 1413129 • 1 spm; same collection data as for preceding; GenBank : MK472139 , MK464511 ; USNM 1413131 • 1 spm; same collection data as for preceding; GenBank : MK472140 , MK464512 , MK480746 ; USNM 1413132 • 1 spm; same collection data as for preceding; GenBank : MK472141 , MK464513 , MK480747 ; USNM 1413133 • 1 spm; same collection data as for preceding; GenBank : MK472142 , MK464514 , MK480748 ; USNM 1413134 • 1 spm; same collection data as for preceding; GenBank : MK472143 , MK464515 ; USNM 1413135 • 1 spm; same collection data as for preceding; GenBank : MK472144 , MK464516 ; USNM 1413136 • 1 spm; same collection data as for preceding; GenBank : MK472145 , MK464517 ; USNM 1413137 • 1 spm; same collection data as for preceding; GenBank : MK472146 , MK464518 ; USNM 1413138 • 12 spms; Shasta Co., Goose Valley, unnamed spring run on W side of Goose Valley Rd and Goose Valley , ca 0.8 km N of Goose Creek, approx. 4.5 mi N of Route 299; 40.9329, -121.7264; 16 Sep. 2007; T. Grace leg.; USNM 1111796 • 15 spms; Shasta Co., Grace Lake [near Shingletown]; [40.4833, -121.8636]; 9 Nov. 1963; CASIZ 57480 • 30 spms; Shasta Co., Hat Creek at Bridge Campground ; 40.73, -121.4371; 10 Sep. 2015; E.E. Strong and P. Bouchet leg.; USNM 1413102 • 1 spm; same collection data as for preceding; GenBank : MK472127 , MK464499 ; USNM 1413092 • 1 spm; same collection data as for preceding; GenBank : MK472128 , MK464500 , MK480737 ; USNM 1413093 • 1 spm; same collection data as for preceding; GenBank : MK472129 , MK464501 ; USNM 1413094 • 1 spm; same collection data as for preceding; GenBank : MK472130 , MK464502 , MK480738 ; USNM 1413095 • 1 spm; same collection data as for preceding; GenBank : MK472131 , MK464503 , MK480739 ; USNM 1413096 • 1 spm; same collection data as for preceding; GenBank : MK472132 , MK464504 , MK480740 ; USNM 1413097 • 1 spm; same collection data as for preceding; GenBank : MK472133 , MK464505 , MK480741 ; USNM 1413098 • 1 spm; same collection data as for preceding; GenBank : MK472134 , MK464506 , MK480742 ; USNM 1413099 • 1 spm; same collection data as for preceding; GenBank : MK472135 , MK464507 , MK480743 ; USNM 1413100 • 1 spm; same collection data as for preceding; GenBank : MK472136 , MK464508 , MK480744 ; USNM 1413101 • 6 spms; Shasta Co., Lamoine, side creek going into Sacramento River ; [40.9753, -122.4311]; Aug. 1937; T. Burch and J.Q. Burch leg.; UF 192866 • 5 spms; Shasta Co., Lost Creek, in lava field on N of Wilcox Ranch Rd, W of Hat Creek rim, E of Hat Creek and Hwy 44/89, lower fishing access.; 40.7628, -121.4347; 12 Aug. 2007; T. Grace leg.; USNM 1111863 • 23 spms; Shasta Co., Pit River Canyon (small spring), W side of river 4 mi below Fall River Mills; [40.9851, -121.5126]; C.H. Merriam leg.; USNM 361546 • 108 spms; Shasta Co., Potem Creek, in tributary to Pit River after falls by road; [40.8368, -122.0222]; 17 May 1978; J. Landye leg.; USNM 892366 • 3 spms; Shasta Co., Rainbow Springs, at headwaters of Fall Mill Creek on Lazy S Ranch adjacent to Thousand Springs Ranch ; [41.1111, -121.5511]; 16 May 1978; J. Landye leg.; USNM 1665622 (ex USNM 892373 ) • 1 spm; Shasta Co., S side of Hwy 299, Pit River , Lion’s Club picnic area, W of Pit River camping grounds; 40.9866, -121.513; 1 Sep. 2007; T. Grace leg.; USNM 1665623 (ex USNM 1111864 ) • 14 spms; Shasta Co., S side of Pit River, water source spring at Pacific Gas and Electric plant; [40.9896, -121.5021]; 16 May 1978; J. Landye leg.; USNM 1665624 (ex USNM 892372 ) • 18 spms; Shasta Co., Salt Creek Rd , 1 km S of Fenders Ferry Rd [Salt Ck]; 40.8646, -122.1395; 360 m a.s.l.; 18 Oct. 2011; J. Slapcinsky leg.; UF 448882 • 35 spms; Shasta Co., tributary to Shasta Reservoir, 4.7 road mi from McCloud Bridge , E of McCloud arm [= Nosoni Creek]; [40.9113, -122.2078]; 1 Jul. 1997; J.L. Furnish leg.; CASIZ 223387 • 1 spm; Sierra Co., Downieville, Fiddle Creek [sic]; 20 Sep. 1946; H.P. Chandler leg.; CASIZ 170002 • 26 spms; Sierra Co., North Fork, Yuba River , Downieville ; [39.5583, -120.8275]; ANSP 125085 • 1 spm; Siskiyou Co., headwaters of Fall River ; 1896; R.C. McGregor leg.; ANSP 332330 • 17 spms; Tehama Co., Deer Creek, off FS Rd 28N29, ca 10 air mi NNW of Forest Ranch; [40.0702, -121.7048]; 25 Jul. 2001; USFS Lassen Natl Forest Mollusk Survey 2001; J. Brim Box leg.; CASIZ 165961 • 24 spms; Tehama Co., Deer Creek, off Potato Patch Campground , off SR 32, ca 12 air mi SSE of Mineral; [40.1873, -121.5323]; 23 Jul. 2001; USFS Lassen Natl Forest Mollusk Survey 2001; CASIZ 166030 • 7 spms; Tehama Co., Deer Creek, off SR 32, 0.5 mi N of Alder Creek Campground, ca 11 air mi SE of Mineral ; [40.2163, -121.4917]; 23 Jul. 2001; USFS Lassen Natl Forest Mollusk Survey 2001; CASIZ 166361 • 21 spms; Tehama Co., Lassen Natl Forest, Deer Creek , at lower falls, off FS Rd 27N08, approx. 13 air mi S of Mineral; [40.168, -121.5814]; 24 Jul. 2001; USFS Lassen Natl Forest Mollusk Survey 2001; J. Brim Box leg.; CASIZ 165372 • 15 spms; Tehama Co., unnamed spring off [Tehama] County Rd 769, ca 0.4 mi E of SR 36/89, ca 13 air mi WNW of Chester; [40.3406, -121.4605]; 21 Jun. 2001; USFS Lassen Natl Forest Mollusk Survey 2001; CASIZ 166013 • 26 spms; Tehama Co., W Branch of Feather River, Morgan Springs ; [40.3846, -121.5137]; 1898; R.C. McGregor leg.; ANSP 73512 • 2 spms; Shaw Creek, at Fire Creek Fire Control Station , Shasta Co. [sic, possibly Shaw Creek, Tehama Co.]; [40.2096, -121.9511]; 17 May 1978; J. Landye leg.; USNM 892381 .

Description

SHELL. Thin, moderate in size, reaching ~ 2 cm in length; turriform, conical in shape, spire height moderate ( Fig. 17 ). Whorls convex, suture moderately impressed. Aperture oval in shape, lip smooth, simple to weakly sinuous. Spiral sculpture of numerous, indistinct, fine striae. Axial sculpture of fine, weakly prosocline to opisthocyrt or sinuous growth lines; irregular varices occasionally present confined to upper spire. Shell light brown to dark purplish- or reddish-brown, occasionally with a lighter subsutural band. Interior of aperture light, yellowish brown to dark purple.

RADULA. Rachidian narrowly rectangular, wider than tall, basal margin flattened, with slight, bluntly rounded median and lateral projections; basal denticles lacking or vestigial ( Fig. 18 ). Upper margin slightly concave with cutting edge bearing central, elongate conical cusp, and two to three stout, conical denticles on each side. Lateral teeth with prominent triangular cusp flanked by ~three inner and three to five outer, triangular denticles, and frequently a membranous outermost denticle. Marginal teeth with broadly rounded cutting edges and long, slender, flattened shafts with membranous flanges along inner and outer edges. Narrow inner flanges along distal half to third of inner marginal teeth and extending almost to tooth bases of outer marginal teeth; broad outer flanges extending almost to tooth bases. Inner marginal teeth with ~four and outer marginal teeth with ~five flattened denticles.

Distribution and ecology

Primarily in springs, spring runs, and small creeks in the southern Pit River system; possibly extending into larger creeks and rivers in eastern Sacramento River tributaries and the northern Mokelumne River watershed of the Sierra Nevada ( Fig. 14C ).

Remarks

Given the uncertainty of the circumscription of this species in the southern part of its range (see below), the preceding description is based on sequenced and topotypic specimens. Although not present in all specimens, the species may be distinguished by the presence of irregular varices on the upper whorls of some specimens (e.g., Fig. 17V, X–Y ). These can be seen in the sequenced holotype and topotypic specimens ( Fig. 17A, U ) and are more irregular and widely spaced than the plications seen in J. nigrina with which it overlaps in distribution in the western part of its range (see J. nigrina below).

Distribution

The main part of the distribution of J. douglasi sp. nov. lies in the southern Pit River drainages in Shasta and Lassen Counties where it overlaps with J. occata , although individuals of the two species are rarely found in syntopy; only three lots with mixtures of the two were found in the USNM collections [USNM 1111864, USNM 1665623 (ex USNM 1111864); USNM 892372, USNM 1665624 (ex USNM 892372); USNM 892373, USNM 1665622 (ex USNM 892373)], and one species is always numerically dominant. Sequenced specimens reported in Campbell et al. (2016) expand the distribution into the eastern Sacramento River tributaries of southern Lassen County and northern Plumas County. Specimens consistent with the J. douglasi sp. nov. morphotype from McCloud River (Nosoni Creek; CASIZ 223387) and upper Sacramento River drainages (Lamoine; UF 192866) extend the distribution slightly to the west where it overlaps with J. nigrina , but this should be confirmed with sequenced specimens.

Populations from Sacramento River drainages of the western foothills of the Sierra Nevada have been attributed primarily to J. nigrina (e.g., Lowe 1916; Taylor 1981; Frest & Johannes 1995b; Brim Box 2002; Brim Box et al. 2005), rarely to J. interioris (e.g., Lee et al. 2006; Ó Foighil et al. 2009), and more recently were noted to comprise at least one new species ( Frest & Johannes 2007). These are difficult to identify with certainty in the absence of molecular data but are here cautiously interpreted as representing J. douglasi sp. nov. When preserved, the early teleoconch is typically smooth, narrow, with convex whorls and a deeply impressed suture, and sometimes (CASIZ 165961, CASIZ 166013) shows the varices seen more frequently in the northwest part of the range. The teleoconchs are usually smooth, but occasionally spirally grooved or with indistinct spiral striae and are rarely banded. If these records can be verified as conspecific with J. douglasi , scattered museum records place the species, at least historically, in eastern Sacramento River drainages in Butte, Sierra, Nevada, El Dorado, and Sacramento Counties in the Feather River, Yuba River, and American River Basins. These areas coincide with the Sierra Nevada goldfields and were heavily affected by placer mining activities including hydraulic mining and dredging. However, modern museum records from the mid 1990’s and surveys by Frest & Johannes (2007; as Juga n. spp.) confirm that Juga is surviving in highly fragmented populations in the southern Lassen National Forest, the Plumas National Forest, and the Tahoe National Forest in Nevada County (CASIZ 112152, 113099, 113100). A 2018 iNaturalist record (https://www.inaturalist.org/observations/15172449) from the Cosumnes River, El Dorado County, indicates that Juga populations are persisting in the Mokelumne River watershed, which borders the Sacramento River watershed to the south. One historical lot (ANSP 145847) from Strawberry Creek on the UC Berkeley campus in the East San Francisco Bay Area contains spirally grooved specimens ( Fig. 17T ) similar to some from Table Mountain in Butte County [USNM 119284 ( Fig. 17Q ), ANSP 27568] and North San Juan in Nevada County [CASIZ 30310 ( Fig. 17R, Z )] and is hypothesized also to be conspecific with J. douglasi . However, given the range of morphological variation seen in species of Juga , it is possible that populations from the Sierra Nevada represent mixtures of J. occata and J. douglasi , or an as yet undescribed form.

Common name

The common name for this species is the Douglas Juga . The OTU referred to as J. (O.) nigrina ( Frest & Johannes 1995b = Black Juga ) from the Upper Sacramento System is a mixture of true J. nigrina and J. douglasi sp. nov. as circumscribed here. The OTU referred to as J. (O.) “ nigrina ” ( Frest & Johannes 1995b = Smooth River Juga ) from the Upper Sacramento System is a mixture of J. canella sp. nov. and J. douglasi as circumscribed here.

Figures

Fig. 17. Shell morphology of Juga douglasi sp. nov. A. Holotype, USNM 1413130. B–F. Sequenced vouchers. B. USNM 1413138. C. USNM 1413133. D. USNM 1413095. E. USNM 1413096. F. USNM 1413093. G. USNM 1665624 (ex USNM 892372). H. UF 448882. I. CASIZ 223387. J. UF 520318. K. USNM 892366. L. CASIZ 57480. M. ANSP 73522. N. ANSP 73510. O. CASIZ 166013. P. CASIZ 165372. Q. USNM 119284. R. CASIZ 30310. S–T. ANSP 145847. U. USNM 1413139. V. CASIZ 166013. W. CASIZ 165372. X. UF 520318. Y. UF 448882. Z. CASIZ 30310. Scale bar = 1 cm.

Fig. 18. Radular morphology of Juga douglasi sp. nov., holotype (USNM 1413130). A. View of the anterior radular ribbon. B. Detail of cutting edge of rachidian and lateral teeth. C. Detail of lateral teeth cusps. D. Detail of rachidian cusps. E. Inner and outer marginal teeth. F. Detail of inner and outer marginal teeth cusps. Scale bars: A = 300 µm; B, E = 100 µm; C–D, F = 50 µm.

Fig. 14. Distribution maps. A. Juga caerulea sp. nov. B. Juga canella sp. nov. C. Juga douglasi sp. nov. Red stars, type localities; black dots, sequenced specimens; gray dots, unsequenced museum material. Abbreviations: CA = California; NV = Nevada; OR = Oregon; WA = Washington.