Amynthas minimus ( Horst, 1893 )

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 : 511-512

publication ID	https://doi.org/10.11646/zootaxa.4179.3.7
publication LSID	lsid:zoobank.org:pub:B0854097-2CA6-41CF-B44C-8A0F49819DA0
DOI	https://doi.org/10.5281/zenodo.5671383
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scientific name	Amynthas minimus ( Horst, 1893 )
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7. Amynthas minimus ( Horst, 1893)

( Figures 1 View FIGURE 1 E, 13)

Perichaeta minima Horst, 1893: 66 .

Pheretima minima — Gates 1982: 57.

Amynthas minimus — Sims & Easton 1972: 236. Reynolds 1978: 127; 2011: 275. Reynolds & Wetzel 2004: 88; 2008: 180.

Data sources. Gates (1972, 1982); Chang et al. (2009a; for color of live specimens).

Diagnosis. Size 20–56 mm by 1.5– 2 mm. Segment numbers 77–115. Color of live specimens light red to reddish white. Male pores paired in XVIII, on a relatively large porophore. Post-clitellar genital markings unpaired, small mid-ventral tubercles, pre-setal on some of XVII, XIX–XXI. Spermathecal pores paired in 5/6 or absent. Preclitellar genital markings paired small pre-setal tubercles on some of V–VIII. Female pore single in XIV. First dorsal pore 11/12 or 12/13. Spermathecae present or absent; when present, one pair or single in VI, large. Prostate glands present or absent; when present, large, extending through some or all of XVI–XXIII. Intestinal caeca simple, extending anteriorly to XXIII.

Remarks. Easily distinguished from most pheretimoid species by its body size, A. minimus is one of the smallest pheretimoid earthworms in the world. It was first recorded in the continental US in 1969 in Louisiana ( Gates 1982). Reproduction of this species is parthenogenetic.

References

Chang, C. - H., Shen, H. - P. & Chen, J. - H. (2009 a) Earthworm fauna of Taiwan. National Taiwan University Press, Taipei, 174 pp.

Gates, G. E. (1972) Burmese earthworms - Introduction to systematics and biology of megadrile oligochaetes with special reference to Southeast Asia. Transactions of the American Philosophical Society, 62, 5 - 324. http: // dx. doi. org / 10.2307 / 1006214

Gates, G. E. (1982) Farewell to North American megadriles. Megadrilogica, 4, 12 - 77.

Horst, R. (1893) Earthworms from the Malay Archipelago. Zoologische Ergebnisse einer reise in Niederlandisch Ost-Indien, 3, 28 - 77.

Reynolds, J. W. (1978) The earthworms of Tennessee (Oligochaeta). IV. Megascolecidae, with notes on distribution, biology and a key to the species in the state. Megadrilogica, 3, 117 - 130.

Reynolds, J. W. & Wetzel, M. J. (2004) Terrestrial Oligochaeta (Annelida: Clitellata) in North America north of Mexico. Megadrilogica, 9, 71 - 98.

Sims, R. W. & Easton, E. G. (1972) A numerical revision of the earthworm genus Pheretima auct. (Megascolecidae: Oligochaeta) with the recognition of new genera and an appendix on the earthworms collected by the Royal Society North Borneo Expedition. Biological Journal of the Linnean Society, 4, 169 - 268. http: // dx. doi. org / 10.1111 / j. 1095 - 8312.1972. tb 00694. x

Figures

FIGURE 1. Color photographs of live individuals of (A) Amynthas agrestis, (B) Amynthas corticis, (C) Amynthas gracilis, (D) Amynthas hupeiensis, (E) Amynthas minimus, (F) Amynthas morrisi, (G) Amynthas tokioensis, (H) Metaphire californica, (I) Metaphire hilgendorfi, (J) Metaphire posthuma, (K) Pithemera bicincta, and (L) Polypheretima elongata, showing interspecific variations in colorations and body shapes. Specimens are from US (A, B, D, G, I) and Taiwan (C, E, F, H, J, K, L). Photo credit: Chih-Han Chang (A, B, D, E, G, H, I) and Wen-Jay Chih (C, F, J, K, L). The photographs of A. minimus and M. californica have been previously presented in Chang et al. (2009 a).