Haplotaxoides sp. C

Haplotaxoides sp. C

( Fig. 4E View Figure 4 )

Material examined: USNM 1716322 About USNM : USA, Oregon, Jefferson Co., Metolius River above Camp Sherman, near Metolius Spring, 44.4387 °N, 121.6392 °W, 4 Dec 2019 GoogleMaps ; anterior end of immature worm on slide, posterior end analysed for DNA (CE36019); for molecular data, see Table 1. S View Table 1 . Fend collection: 4 Jun 2018; four whole mounts; 4 Dec 2019; eight whole mounts. All collected by S. Fend.

Description

Length 21–37 mm, maximum diameter 164–250 μm; 95–180 segments. Dorsal chaetae slightly sigmoid, length 40–56 μm, diameter 2–3 μm, nodulus 0.40–0.53 the chaetal length from the tip ( Fig. 4E View Figure 4 ). Ventral chaetae strongly hooked, some with dorsal keel at tip; length 88–110 μm, diameter 5–6 μm, nodulus at 0.30– 0.38 the chaetal length from the tip. Cuticular layer of body wall 2–3 μm. Mouth, pharynx, and other gut characters as described above. Coelomocytes very sparse, only seen in anterior segments, 8–10 μm long; ventral glands to 150 μm, usually 3/bundle.

Other Haplotaxoides material (not analysed for DNA)

Material examined: All material in S. Fend collection, collected by S. Fend unless otherwise noted; all specimens immature or with developing gonads: USA, California, Santa Clara Co., Coyote Creek above reservoirs, below Gilroy Hot Springs, 24 Apr 2011; two whole mounts. Monterey Co. , Nacimiento River below upstream camp, 17 Mar 2008; one whole mount. Humboldt Co. , Van Duzen River , 27 May 2002; one whole mount. Eel River at Elk Creek , 24 Jun 2001; one whole mount. Butte Co. , North Fork Feather River , 1 Oct 1999, collected by W. Fields ; three whole mounts. Colusa Co., Stony Creek at Stonyford , 4 Nov 2002; five whole mounts. Colorado, South Platte River drainage, hyporheic samples, 2018, collected by S.J. Taylor ; four whole mounts. Idaho, Lemhi Co., Hayden Creek , 30 Apr 2000, collected by D.L. Gustafson ; four whole mounts. Nevada, Washoe Co., Lake Tahoe , 59 m depth, collected by A. Caires ; two whole mounts. Illinois, St. Clair Co., Stemler Cave, 2 miles north-east of Columbia , Jun 1999, collected by S.J. Taylor ; one whole mount. Missouri, Carter Co., Phillips Spring, Ozark National Scenic Riverways , 29 Jul 2019, collected by D.E. Bowles ; three whole mounts. Shannon Co., Pulltite Spring, Ozark National Scenic Riverways , 24 Jul 2018, collected by D.E. Bowles ; three whole mounts.

Remarks

All specimens from these sites resembled the type material of Haplotaxoides decipiens in body form, single chaetae, thick cuticle, and gut morphology. All had small, sigmoid dorsal chaetae and larger, distally hooked ventral chaetae present in all segments from II. All had the characteristic coelomocytes, midventral glands, and nephridia. Where partially formed gonads were visible, they were invariably located in XII – XIII (testes) and XV only (ovaries).

Anterior segments in three specimens from the North Fork Feather River (California) and a single specimen from Fall Creek, Oregon have 2–4 prominent bands of cells that are distinctly enlarged, appearing vacuolized; these are present, but less frequent in posterior segments. The epidermis of most Haplotaxoides specimens is thin (3–12 μm) and uniform in anterior segments.