Prophysaon andersonii

Family

Anadenidae

Species

Prophysaon andersonii (Cooper, 1872)

Common Name

Reticulate taildropper

Description

A mature, adult slug can attain a length of approximately 64 mm. The pale brown, red-grey or yellow body of the slug is usually clouded with darker shades. The tentacles are usually dark brown. This slug has a characteristic diamond-mesh pattern on the dorsal surface of its body, due to the arrangement of the tubercles. The pale, finely granulated mantle often has two, dark lateral lines running its length. The pneumostome (breathing pore) is anteriorly or medially located on the mantle. The fringe of the foot is pale and does not possess any dark bands; however, faint lines may be observed. The sole is brilliant white to dirty white with a highly contrasting mucus color (lemon yellow to orange). The tail is acute in shape. When contracted, the body of the slug is tadpole-shaped.

The genus Prophysaon has nine recognized species. According to Pilsbry's (1948), there are two species groups (subgenera) in this genus:

1. Prophysaon: In this group, the epiphallus is extremely long and slender except it enlarges abruptly near the insertion in the penis.

  • P. boreale (Northern taildropper): Body finely reticulate, with pale dorsal line. Penis not much shorter than muscular body of the epiphallus.
  • P. foliolatum (Yellow-bordered taildropper): Body finely reticulate, with pale dorsal line. Penis much shorter than muscular body of the epiphallus. Large species (~ 90 mm).
  • P. andersonii (Reticulate taildropper): Body finely reticulate, with pale dorsal line. Penis much shorter than muscular body of the epiphallus. Small species (~ 64 mm).
  • P. coeruleum (Blue-gray taildropper): Body not finely reticulate, no pale dorsal line. Muscular body of the epiphallus very short. Uniform blue-gray slug.
  • P. dubium (Papillose taildropper): Body not finely reticulate, no pale dorsal line. Muscular body of the epiphallus long. Purple-gray slug.

2. Mimetarion: In this group, the epiphallus is of moderate length and slender. Initially, the epiphallus is much wider than the vas deferns, but tapers where both structures meet.

  • P. fasciatum (Banded taildropper): Vagina and spermathecal duct slender and very long. Penis sac broad.
  • P. obscurum (Mottled taildropper): Vagina and spermathecal duct slender and very long. Penis sac narrow.
  • P. vanattae (Scarlet-backed taildropper): Vagina and spermathecal duct stout and very short. Cavity of epiphallus possess two longitudinal ridges.
  • P. humile (Smoky taildropper): Vagina and spermathecal duct stout and very short. Cavity of epiphallus possess one longitudinal ridge.

Native Range

North America

Distribution

North America:

  • U.S.: Alaska to California and east to Idaho
  • Canada: British Columbia

Ecology

This slug will occur in wooded areas, gardens and disturbed habitats. It has the ability to self-amputate and regenerate its tail. The site of potential amputation characteristically has a diagonal constriction and a may appear as a dark line on the sole of the foot.

Synonyms

  • Arion andersonii, Cooper, 1872, Proc. Acad. Nat. Sci. Phila., p148, pl. 3, figs. F1-5.
  • Prophysaon hemphilli Bland & Binney, 1873, Ann Lyc. N.H. of N.Y., 10: 295, pl. 13, figs. 2, 4, 6-8; W.G. Binney, 1878, Terr. Moll., 5: 238, figs. 137-139, pl. v, fig. 1 (teeth), pl. xiii, fig. h (genitalia), "specimens from Mendocino county" excluded.
  • P. pacificum Cockerell, 1890, Nautilus 3: 111., 1891, Nautilus, 5: 31; 1897, 11: 77; W.G. Binney, 1890, Third Suppl., Bull. M.C.Z., 19: 210, pl. 7. Figs. B,F,H.
  • P. flavum Cockerell, 1890
  • P. andersonii var pallidum Cockerell, 1891, Nautilus, 5:31
  • P. andersonii var. marmoratum Cockerell, 1892, The Conchologist, 2: 72
  • P. andersonii var suffusum Cockerell, 1893, The Conchologist, 2: 118; 1897, Nautilus, 11: 79

References

Forsyth 2004; Ovaska et al. 2004; Pilsbry 1948

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