Amazoniscus arlei, LEMOS DE CASTRO, 1967

Schmidt, Christian, 2007, Revision of the Neotropical Scleropactidae (Crustacea: Oniscidea), Zoological Journal of the Linnean Society 151, pp. 1-339 : 64

AMAZONISCUS ARLEI LEMOS DE CASTRO, 1967

Amazoniscus arlei Lemos de Castro, 1967 – Lemos de Castro (1969); Souza-Kury (1998 *); Leistikow & Wägele (1999 *).

Material examined

Types: One ♂, one juvenile, one isolated pleon, one manca, paratypes ( Brazil, Pará, Belém, Parque do Museu Goeldi , leg. H. Schubart, February 1964, MNRJ 3313 ) ; three ♂, two ♀ paratypes ( Brazil, Amapá, Serra do Navio , leg. R. Arlé, 10 December 1959, MNRJ 6208 ) .

Other samples: One ♀ m ( Brazil, Pará, Mangabeira , Tocantins, sob pau podre, leg. Osvaldo Cunha, May 1953, MNRJ 3312 ) ; one ♂, one ♀ m, one juvenile ♂, one juvenile ♀ ( Brazil, Pará, Belém, Parque do Museu Goeldi , leg. H. Schubart, 5 February 1967, MNRJ 3314 ) ; one ♂ [ Brazil, MG (= Minas Gerais), Leopoldina , 21°31′ S, 42°38′ W, leg. L. A. Souza, 10 July 1983, MNRJ 8198 ] ; one ♀ m, one ♀, one immature ♀? ( Brazil, Jacarepaguá, Estrada de Barra, ‘ No chão, sob folhas’, leg. Lemos de Castro, 20 August 1972, MNRJ 3318 ) , one ♀ m, one ♀ ( Brazil, RJ, Tijuca, Sítio antigo na Rua Maracanã , leg. Schubart, 27 September 1939, MNRJ 3319 ) ; one ♀ ( Brazil, Pará, Jacareacanga , leg. M. Alvarenga, December 1968, MNRJ 3320 ) (Map Fig. 196) .

Description ( Figs 189–195 )

Male 10.1 × 4.1 mm, adult female 5.3 × 2.3 mm, cephalothorax 1.39 mm /6.5 × 2.8 mm, cephalothorax 1.67 mm.

Endoantennal conglobation ability (not exoantennal, as described by Lemos de Castro), tergites smooth. Frontal shield of cephalothorax slightly but distinctly exceeding the vertex, behind it with a transverse furrow. Linea frontalis present, but weak and medially obsolete. Coxal plates all without schisma or lobes, the first coxal plates with a sinuous portion near the hind corner. Eyes composed of 20 ommatidia (not nine, as indicated in the original description) (coloration not preserved), smaller specimens with lower number of ommatidia (e.g. male 5.9 × 2.6 mm, cephalothorax 1.55 mm, 12/13 ommatidia).

Pereiopod 1 with longitudinal antenna-cleaning brush composed of long scales. Male pereiopods 1–3 with ventral scale-fields on merus and carpus. All pereiopods covered with somewhat irregular, distally projecting scales. Ventral large setae apically furcate, their tip exceeded by free protruding end of the sensory hair. Male pereiopod 7 ischium with a process on caudal side of ventrodistal corner, merus with an interrupted ventrolateral ridge on frontal side. Pereiopod 7 basis and ischium on frontal face with distinct scale-rows belonging to the water-conducting system.

Pleopod 1 and 2 exopodites with distinct respiratory fields, pleopod 3–5 exopodites without respiratory fields. Male pleopod 1 exopodite distally with a narrow tip, endopodite stout, distally outcurved, but the extreme apex bent mediad. In smaller (immature?) males distal lobe of exopodite 1 is shorter and simply bent laterally. Row of small, slender spineshaped setae along spermatic furrow is strongly curved subapically and, after a right angle, the distalmost three setae in a straight row. Male pleopod 2 endopodite only slightly exceeding exopodite, the latter with a hairy field along medial margin. Exopodite 1 with simple marginal seta on lateral and medial margins, exopodites 2 and 3 with marginal setae only on lateral margin. Also, the lateral margins of the respiratory fields bear marginal setae.

Remark

The paratype male described here differs from the figures given by Lemos de Castro (1969) by the shorter process on ischium 7 and a much narrower and longer distal lobe of the pleopod 1 exopodite. The other males have the distal lobe of the pleopod 1 exopodite shorter, more like the specimen illustrated by Lemos de Castro, but in contrast to this, they lack a distal process on ischium 7. As these specimens are about half as large as the paratype described above, the differences may be explained by the assumption that the smaller specimens are immatures with less developed male sexual characters. However, more material needs to be examined before this assumption, or the alternative assumption, that the smaller specimens represent a distinct species, can be substantiated. If there actually are two species, then the larger male (paratype) would need a new name, provided that the specimen on which the illustrations in Lemos de Castro (1969) are based can be considered to be the holotype. However, this specimen was not available for study.

Figures

Figure 189. Amazoniscus arlei Lemos de Castro, 1967: paratype ♂, 10.1 × 4.1 mm (Brazil, Pará, Belém, Parque do Museu Goeldi, leg. H. Schubart, February 1964, MNRJ 3313).

Figure 190. Amazoniscus arlei Lemos de Castro, 1967: paratype ♂, 10.1 × 4.1 mm, pereiopod 7 (Brazil, Pará, Belém, Parque do Museu Goeldi, leg. H. Schubart, February 1964, MNRJ 3313).

Figure 191. Amazoniscus arlei Lemos de Castro, 1967: paratype ♂, 10.1 × 4.1 mm, pleopods 1–3 (Brazil, Pará, Belém, Parque do Museu Goeldi, leg. H. Schubart, February 1964, MNRJ 3313).

Figure 192. Amazoniscus arlei Lemos de Castro, 1967: ♂, 5.8 × 2.4 mm, cephalothorax 1.54 mm, pereiopods 1–3 frontal, uropod dorsal (Brazil, Minas Gerais, Leopoldina, 21°31′ S, 42°38′ W, leg. L. A. Souza, 10 July 1983, MNRJ 8198).

Figure 193. Amazoniscus arlei Lemos de Castro, 1967: ♂, 5.8 × 2.4 mm, cephalothorax 1.54 mm, pereiopods 4–6 frontal, uropod ventral (Brazil, Minas Gerais, Leopoldina, 21°31′ S, 42°38′ W, leg. L. A. Souza, 10 July 1983, MNRJ 8198).

Figure 194. Amazoniscus arlei Lemos de Castro, 1967: ♂, 5.8 × 2.4 mm, cephalothorax 1.54 mm, pereiopod 7 frontal and caudal, pereiopod 7 dactylus, second antenna (Brazil, Minas Gerais, Leopoldina, 21°31′ S, 42°38′ W, leg. L. A. Souza, 10 July 1983, MNRJ 8198).

Figure 195. Amazoniscus arlei Lemos de Castro, 1967: ♂, 5.8 × 2.4 mm, cephalothorax 1.54 mm, pleopods 1–5 (Brazil, Minas Gerais, Leopoldina, 21°31′ S, 42°38′ W, leg. L. A. Souza, 10 July 1983, MNRJ 8198).