Amynthas rodericensis ( Grube, 1879 )

Chang, Chih-Han, Snyder, Bruce A. & Szlavecz, Katalin, 2016, Asian pheretimoid earthworms in North America north of Mexico: An illustrated key to the genera Amynthas, Metaphire, Pithemera, and Polypheretima (Clitellata: Megascolecidae), Zootaxa 4179 (3), pp. 495-529 : 513

9. Amynthas rodericensis ( Grube, 1879)

( Figure 15 )

Perichaeta rodericensis Grube 1879: 554 .

Pheretima rodericensis — Gates 1954: 239; 1958: 31; 1963: 14; 1982: 63. Amynthas rodericensis — Sims & Easton 1972: 235. Reynolds 1978: 127; 2010: 149; 2011: 277. Reynolds & Wetzel 2004: 88; 2008: 180.

Data sources. Gates (1937, 1954, 1972, 1982).

Diagnosis. Size 55–150 mm by 3–10 mm. Segment numbers 80–100. Color of live specimens unknown. Male pores paired in XVIII, small, superficial, on small, circular porophores. Post-clitellar genital markings paired, oval, large, median to male pores, across 17/18 and/or 18/19. Spermathecal pores four pairs in 5/6/7/8/9, dorsal. Preclitellar genital markings absent. Female pore single in XIV. First dorsal pore 11/12 or 12/13. Spermathecae four pairs in VI–IX, duct shorter than ampulla; diverticulum stalk longer than the duct, seminal chamber elongate, ellipsoidal, or moniliform. Prostate glands paired, extending from XVI, XVII to XXI, XXII. Intestinal caeca paired in XXVII, simple, extending anteriorly to XXIV–XXV.

Remarks. The first record of A. rodericensis in the continental US was in 1950 in Lutz, Florida ( Gates 1954). This species is the only US pheretimoid earthworm with dorsally positioned spermathecal pores. Identification of this species can easily be achieved by combining this unique spermathecal pore position and the genital markings in the male pore area. Reproduction of A. rodericensis is amphimictic.

Figures

FIGURE 15. Amynthas rodericensis. (A) Both male pores (arrows) and the associated genital markings, showing two on each side. (B) Right male pore (arrow) with only the post-setal genital marking. (C) Right male pore with no genital marking. A – C all from USNM 125143, different specimens. (D) Paired dorsal spermathecal pores in 5 / 6 / 7 / 8 / 9 (arrows); dorsal view. The relatively light-colored pores can usually be easily seen due to the relatively dark dorsal pigmentation (USNM 125161). (E) Left spermathecae in VII – IX. (F) Left prostate gland and its duct (arrow). (G) Left intestinal caecum. E – G from the same specimen in USNM 125143.