Studies on the Life History and the Ecology of the Hothouse Millipede, Orthomorpha gracilis (C. L. Koch 1847)
1943; University of Notre Dame; Volume: 29; Issue: 3 Linguagem: Inglês
10.2307/2421156
ISSN1938-4238
Autores Tópico(s)Marine Biology and Ecology Research
ResumoLike other polydesmid millipedes, Orthomorpha gracilis is flattened dorsoventrally. The keels or carinae are nearly horizontal and less than one-fourth the width of the body cavity. The 20 post-cephalic somites bear 30 or 31 pairs of legs, depending upon whether the specimen is a male or a female. The gonopods, a pair of highly modified walking appendages present only in adult males, are on the seventh post-cephalic somite between the seventh and eighth pairs of legs. Each gonopod (Fig. 1) is composed of a prominent basal joint and an apical joint with a short cushion-like hirsute base, a stout, slightly curved shaft, and four terminal curved prongs. Male specimens vary between 18.5 and 19.9 mm. in length and 2.0 and 2.2 mm. in width; female specimens vary between 19.4 and 22.2 mm. in length and 2.0 and 2.5 mm. in width. Recently moulted specimens are creamy white, but before they leave the moulting chamber the color may change to light brown. In the oldest specimens the dorsum is a deep chestnut brown or black, the keels are bordered with lemon yellow, the sides are chestnut brown, the sterna and basal joints of the Iegs are pallid, the distal joints of the legs and the apex of the body are light brown, and the antennae and vertex are dark brown. Immature specimens of the later stadia, which greatly outnumber mature specimens in most collections, resemble the latter closely in shape, but are easily distinguished by their smaller size, paler color, absence of mature gonopods, and smaller number of post-cephalic somites. Stadia I and II are shown in figures 2 and 3.
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