Amynthas loveridgei ( Gates, 1968 )

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 : 510-511

6. Amynthas loveridgei ( Gates, 1968)

( Figure 12 )

Pheretima loveridgei Gates, 1968: 257 ; 1982: 57.

Amynthas loveridgei — Sims & Easton 1972: 236. Reynolds 1978: 127; 2011: 274. Reynolds & Wetzel 2004: 88; 2008: 180. Blakemore 2014: 129, 130.

Data sources. Gates (1968, 1982); Blakemore (2014); this study (USNM 136910 (syntypes), 125052, 125056).

Diagnosis. Size 90–113 mm by 4–6 mm. Segment numbers 118–169. Color of live specimens unknown. Male pores paired in XVIII, sitting near the lower edge on a pre-setal genital marking. Post-clitellar genital markings 3– 6 papillae or tubercles on each side on XVIII; typically three, arranged in a triangle (one lateral, one pre-setal, and one post-setal), often the anterior-most marking extends posteriorly to contain the primary male pore. All markings surrounded by deep, concentric furrows. Spermathecal pores two pairs in 5/6/7. Pre-clitellar genital markings present, one in front of and one behind each spermathecal pore, the latter more median to the pore. Female pore single in XIV. First dorsal pore 10/11 or 11/12. Spermathecae two pairs in VI–VII, variable in size, duct slender, as long as ampulla; diverticulum small or degenerated, usually shorter than the respective spermatheca, with a slender stalk and an ellipsoidal to pear-shaped seminal chamber. Prostate glands absent or well developed; when present, large, extending from XVI, XVII to XXIII, XXIV. Intestinal caeca paired in XXVII, simple, variable in size, extending anteriorly as far as XXIII.

Remarks. One of the two pheretimoid species originally described from the US, A. loveridgei was first recorded in 1966 ( Gates 1968) in Greenville, Madison County, Florida. In the US this species has been reported so far only in Georgia, Florida, and Minnesota. Reproduction of A. loveridgei is parthenogenetic. It can be easily confused with A. morrisi . Gates separated the two species mainly by their pre-clitellar genital markings and segment numbers. In fact, the specimens of A. loveridgei almost always look more slender than those of A. morrisi , and the two species can further be distinguished by the locations of male pores with respect to the adjacent genital markings. The syntypes in the Smithsonian Institution National Museum of Natural History ( USNM 136910 ) and the British Museum of Natural History have the same collection data (27 May, 1966, Honey Lake , 5 miles west of Greenville , Madison County, Florida, USA) . The syntypes at USNM have 22 adults and 40 subadults, including individuals with three or four genital markings in the male pore area. The specimens are in formalin and wellpreserved, but the morphology of the male pore area in the syntypes is not as clear as that in USNM 125052 (from Georgia, USA) and USNM 125056 (from Minnesota, USA) . From the latter two samples, it is now clear that the primary male pore is on the lower edge of the pre-setal genital marking, on top of the presumed setal line. While the primary male pores are generally not visible in the USNM syntype specimens, in the syntype specimen dissected ( Figure 10 C), the primary male pore can barely be seen on the left-hand-side male pore.

Figures

FIGURE 10. Amynthas gracilis. (A) Both male pores (arrows) and the associated genital markings (USNM 125011). (B) Left male pore (arrow) and the associated genital markings (USNM 125019). (C) Right spermatheca in VII. (D) Right prostate gland and its duct (arrow). (E) Right intestinal caecum. C – E from USNM 125021.

FIGURE 12. Amynthas loveridgei. (A) Left male pore and the associated genital markings, showing four papillae and the primary male pore (arrow) at the middle (USNM 125056). (B) Right male pore and the associated genital markings, showing three papillae and the primary male pore (arrow) at the middle (USNM 125056, a different specimen from that in A). (C) Left male pore and the associated genital markings. The primary male pore (arrow) can barely be seen at the middle of three papillae. (D) Two sets of genital markings associated with the two left spermathecal pores (not seen); ventrolateral view. (E) Right spermathecae in VI and VII. (F) Left prostate gland and its duct (arrow). (G) Left intestinal caecum. C – G from one of the syntypes (USNM 136910).