Juga caerulea, 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 : 42-45

Juga caerulea sp. nov.

urn:lsid:zoobank.org:act:B1DFDF9D-9B8B-471B-822A-80F281835610

Figs 12–13

Oxytrema bulbosa – Morrison 1954: 361, 384, pl. 11 fig. 5.

Juga (Oreobasis) n. sp. 5 – Frest & Johannes 1995a: 181. — Johannes 2015: 27.

Juga (Oreobasis) OTU 4 – Campbell et al. 2016: 160.

Blue Mountains Juga – Strong & Whelan 2019: 89.

Etymology

‘ Caeruleus -a -um ’, Latin for ‘blue’, in reference to the Blue Mountains where it is found, and to the bluish to purplish appearance of the aperture interior of fresh collected shells.

Type material

Holotype USA • 1 spm (L = 15.02 mm); Oregon, Grant County, Phipps Meadow along U.S. Hwy 26; 44.5816, -118.4419; 10 Jul. 2014; J.T. Garner and N.V. Whelan leg.; GenBank: MK472115 , MK464487 , MK480730 ; USNM 1294988 .

Other material examined 13 lots, 66 specimens, of which 11 were sequenced.

USA – Oregon • 37 spms; Grant Co., 10 mi E of Austin, Blue Mountains, stream, John Day River drainage; [44.5987, -118.3364]; alt. 4000 ft; 25 May 1939; V.B. Scheffer leg.; USNM 473801 • 18 spms; Grant Co., Phipps Meadow along U.S. Hwy 26; 44.5816, -118.4419; 10 Jul. 2014; J.T. Garner and N.V. Whelan leg.; USNM 1295000 • 1 spm; same collection data as for preceding; GenBank : MK472116 , MK464488 ; USNM 1294989 • 1 spm; same collection data as for preceding; GenBank : MK472117 , MK464489 , MK480731 ; USNM 1294990 • 1 spm; same collection data as for preceding; GenBank : MK472118 , MK464490 , MK480732 ; USNM 1294991 • 1 spm; same collection data as for preceding; GenBank : MK472119 , MK464491 ; USNM 1294992 • 1 spm; same collection data as for preceding; GenBank : MK472120 , MK464492 ; USNM 1294993 • 1 spm; same collection data as for preceding; GenBank : MK472121 , MK464493 ; USNM 1294994 • 1 spm; same collection data as for preceding; GenBank : MK472122 , MK464494 , MK480733 ; USNM 1294995 • 1 spm; same collection data as for preceding; GenBank : MK472123 , MK464495 , MK480734 ; USNM 1294996 • 1 spm; same collection data as for preceding; GenBank : MK472124 , MK464496 , MK480735 ; USNM 1294997 • 1 spm; same collection data as for preceding; GenBank : MK472125 , MK464497 , MK480736 ; USNM 1294998 • 1 spm; same collection data as for preceding; GenBank : MK472126 , MK464498 ; USNM 1294999 .

Description

SHELL. Thin, moderate in size, reaching ~ 1.5 cm in length; turriform, conical in shape, spire height moderate ( Fig. 12 ). Whorls convex, suture moderately impressed. Aperture oval in shape, lip smooth, simple to slightly sinuous. Spiral sculpture of indistinct, fine striae, variable in strength and number. Axial sculpture of fine, orthocline to weakly opisthocyrt or sinuous growth lines; plications lacking. Shell dark brown to black, occasionally with a lighter subsutural band. Interior of aperture bluish in color, occasionally tinged with purple.

RADULA. Rachidian broadly rectangular, wider than tall, with convex lower margin and projecting outer corners; basal denticles lacking or vestigial ( Fig. 13 ). 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 two inner and two to three 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 two-thirds of shafts; broad outer flanges extending almost to tooth bases. Inner marginal teeth with ~four and outer marginal teeth with ~five flattened denticles.

Distribution and ecology

In springs and spring runs of the John Day River drainage, northeastern Oregon ( Fig. 14A ).

Remarks

This species is characterized by its simple, smooth, dark, lightly constructed shell, without distinguishing sculpture; the only known populations are rather uniform in shape and size.

Distribution

Juga caerulea sp. nov. is a highly disjunct and restricted species, occurring in springs and spring runs from a few sites within a single spring complex in Phipps Meadow, the headwaters of the Middle Fork of the John Day River in the Malheur National Forest. One lot collected in 1939 (USNM 473801) indicates that historically it may have occurred in small streams in the area; Morrison (1954: 361, 384, pl. 11 fig. 5) identified these specimens as Oxytrema bulbosa and provided a sketch of the head-foot of a female to show the egg laying groove and ovipositor. However, recent efforts to locate the species elsewhere in the Blue Mountains have been unsuccessful ( Frest & Johannes 1995a). Phipps Meadow, the source of the type material, has been heavily affected by grazing and Frest & Johannes (1995a) considered existing surveys were sufficient to merit a status of Endangered at the Federal or State level. The Blue Mountain Land Trust recently purchased Phipps Meadow with the goal of protecting and restoring the meadow’s riparian habitat (https://bmlt.org/news/phipps-meadow).

Common name

The common name for this species is the Blue Mountain Juga ( Johannes 2015) . It has also been referred to as the Blue Mountains Juga ( Frest & Johannes 1995a; Duncan 2008; Strong & Whelan 2019).

Figures

Fig. 12. Shell morphology of Juga caerulea sp. nov. A. Holotype (USNM 1294988). B–E Sequenced vouchers.B. USNM1294991. C. USNM 1294994. D. USNM 1294996.E. USNM 1294999. F–G. USNM 473801. Scale bar = 1 cm.

Fig. 13. Radular morphology of Juga caerulea sp. nov., holotype (USNM 1294988). 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. Cutting edges of inner and outer marginal teeth. F. Detail of inner and outer marginal teeth cusps. Scale bars: A = 200 µm; B = 100 µm; C, E = 50 µm; D = 40 µm; F = 20 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.