Caecidotea alleghenyensis Lewis & Bowman

Lewis, Julian J., Bowman, Thomas E. & Feller, Daniel J., 2011, A synopsis of the subterranean asellids of Maryland, U. S. A., with description of Caecidotea alleghenyensis, new species (Crustacea: Isopoda: Asellota), Zootaxa 2769, pp. 54-64 : 55-61

Caecidotea alleghenyensis Lewis & Bowman , new species

( Figs 1–4 , 5 a–b, 6)

Material examined. MARYLAND: Garrett Co., Holotype: 8.8 mm 3, Swallow Falls State Park, spring #1, Daniel J. Feller (DJF), 20 May 1992 ( USNM 1138994). Paratypes: 113, 3Ƥ, same data as holotype ( USNM 1138995).

Other material: Spring 35 meters south of Swallow Falls Road, opposite entrance to Maple Glade Road, A. W. Norden (AWN), B. Norden, 17 September 1978, 35Ƥ ( USNM 1138996); springs feeding Deep Creek along west side of Oakland-Sang Road, E. Thompson (ET), 4 April 1986, 13, 4Ƥ ( USNM 1138997); spring flowing into tributary of Herrington Run, DJF, ET, 15 May 1987, 113, 3Ƥ ( USNM 1138998); same locality, DJF, 16 May 1987, 233Ƥ ( USNM 1138999); spring between Herrington Manor Road & Zenas Mellott Road, outlet 0.2 mile [0.3km] SE of Junction, Swallow Falls State Forest, DJF, 17 May 1987, 23 ( USNM 1139000); springs between Herrington Manor Road & Zenas Mellott Road, outlets 0.3, 0.5 and 0.7 mile [0.5, 0.8 and 1.1km] SE of Junction (3 vials), Swallow Falls State Forest, DJF, 20 May 1987, 33 ( USNM 1139001); 334Ƥ ( USNM 1139002); 233Ƥ ( USNM 1139003); spring flowing into tributary of Chisolm Run 1.1 [1.8km] miles east of Hutton (2 vials), DJF, ET, 17 June 1987, 537Ƥ ( USNM 1139004); 734Ƥ ( USNM 1139005); spring below John Friend Cave, DJF, 3 March 1988, 33, 5Ƥ ( USNM 1139006); spring flowing into Sang Run, DJF, 5 March 1988, 13, 1Ƥ; Herrington Run Spring Complex, DJF, 11 May 1988, 13 ( USNM 1139007); spring along Deep Creek, ca. 0.3 miles [0.5km] W Oakland-Sang Run Road, DJF, 4 October 1989, 534Ƥ ( USNM 1139008); spring at confluence of Muddy Creek and Youghiogeny River, AN, 29 August 1993, 43, 4Ƥ ( USNM 1139009); Swallow Falls spring, AWN, 29 August 1993, 36Ƥ ( USNM 1139010).

Diagnosis. Member of the hobbsi Group of Caecidotea ( Lewis 1982, 2009), with male gnathopod propodus armed with well developed processes. Pleopod 1 exopod with plumose setae along distal margin. Pleopod 2 endopod tip with cannula extending parallel to the axis of the endopod, obscured by broadly rounded mesial process and smaller lateral process. Uropods shorter than pleotelson.

Description of male. Longest to 9 mm, approximately 3.6X as long as wide. Body appears unpigmented to naked eye, dorsum of head and pereonites with light diffuse pigmentation under low magnification, most pronounced on head, then decreasing progressively from pereonites 1–4. Eyes small, but distinct and pigmented. Margins of head, pereonites and pleotelson densely setose. Head approximately 1.8X as wide as long, pleotelson moderately produced. Pleotelson slightly longer than wide. Antenna 1 extending to middle of last article of antenna 2 peduncle, flagellum to 10 articles, distal 3 each with 1 esthete. Antenna 2, penultimate article of peduncle about 2/3 length of distal article, flagellum to 50 articles, reaching to pereonite 7 when bent. Mouthparts per diagnosis of genus ( Lewis 2009). Pereopod 1, propodus 1.4X as long as wide, palmar margin proximally with low, stout setae, mature adult with large blade-shaped median process extending well beyond outer margin of recumbent dactyl, distal bicuspid process lower in height relative to median process.

Pleopod 1, protopod approximately 0.6X length of exopod, with 3 retinacula. Exopod approximately 2X as long as wide, lateral margin weakly concave, 3 very elongate plumose setae along distal margin. Pleopod 2, exopod distal article with approximately 20+ elongate plumose setae along margins. Endopod with rounded basal apophysis of varying prominence, tip with 4 processes in anterior view: (1) cannula low, conical, obscured; (2) mesial process broadly rounded, (3) lateral process similar to mesial process, lower and smaller; (4) caudal process broadly rounded forming apex of endopod. Pleopod 3 exopod, proximolateral margin with non-plumose setae, distolateral and apical margin with plumose setae increasing in size toward apical margin. Pleopod 4 exopod with transverse false suture, proximolateral margin with numerous non-plumose setae of moderate length. Pleopod 5 exopod, proximolateral margin with 3 non-plumose elongate setae. Uropods 0.75 length of pleotelson, protopod spatulate, about equidistant in length with endopod, exopod 0.75X length of endopod.

Etymology. The name refers to the Allegheny Mountains. The suggested vernacular name is the Allegheny spring isopod.

Range. Known only from the Allegheny Mountains of western Maryland. Ecological notes. This species is known only from springs, where it was found associated with leaf litter and decaying wood. Ovigerous females were present in collections from May and June, and ranged in size from 3.8 to 6.2 mm in length.

Figures

FIGURE 1. Approximate locations by county of collection for selected groundwater species of Caecidotea in Maryland. Regions indicated within the state are physiographic provinces.

FIGURE 2. Caecidotea alleghenyensis, new species, Garrett Co., Maryland: (a) habitus; (b) head, pereonite 1, antenna 1, proximal articles antenna 2; (c) antenna 1; (d) same, distal articles; (e) antenna 2 peduncle; (f) uropod.

FIGURE 3. Caecidotea alleghenyensis, new species, Garrett Co., Maryland: (a) pleopod 1; (b) pleopod 2; (c) pleopod 3 exopod; (d) pleopod 4 exopod; (e) pleopod 5 exopod.

FIGURE 4. Caecidotea alleghenyensis, new species, Garrett Co., Maryland: (a) pereopod 1, ca. 6 mm male; (b) same, gnathopod; (c) gnathopod of 8 mm male, palmar margin without setae; (d) male pereopod 4. Lirceus sp.: (e) pleopod 3 exopod.

FIGURE 5. Male pleopod 2 endopods: (a – b) Caecidotea alleghenyensis, new species, Garrett Co., Maryland; (c) Caecidotea kenki, Allegany Co., Maryland; (d) Caecidotea nordeni, Washington Co., Maryland; (e) Caecidotea pricei, Washington Co., Maryland; (f) Caecidotea franzi, Garrett Co., Maryland (after Holsinger & Steeves, 1971); (g) Caecidotea vandeli, Washington Co., Maryland; (h) Caecidotea holsingeri, Garrett Co., Maryland; (i) Caecidotea mausi, Washington Co., Maryland. Arrows indicate features in key.