Argulus multicolor Stekhoven 1937

Argulus multicolor Stekhoven, 1937

(Figure 7)

A. multicolor: STEKHOVEN JR. (1937): 16 –20, PL. II, fIGS. 9–14; LEMOS DE CASTRO (1949): 2 –4, fIGS. 1–8, 21–22; LEMOS DE CASTRO (1951): 159 –166, fIGS. 1–8; WEIbEZAHN & CObO (1964): 125, PL. IX–X; LEMOS DE CASTRO (1985): 10, fIGS. 14–16; THATcHER (2006): 392, 394, 398, FIG. 9.14.

Type host. Undetermined (Stekhoven Jr. 1937).

Type locality. Uncertain, once the species was described from Taperinha, in the state of Pará, Brazil, and from Caracas in Venezuela (Stekhoven Jr. 1937).

Other hosts and localities. Rhaphiodon vulpinus Spix & Agassiz, 1829, confluence of the Kuluene and Xingu Rivers, state of Mato Grosso, Brazil (Lemos de Castro 1949); Rhaphiodon sp., Rio das Mortes River, state of Mato Grosso, Brazil (Lemos de Castro 1951); Hydrolycus scomberoides (Cuvier, 1819), Parguaza River, in Bolívar, Venezuela (Weibezahn & Cobo 1964); Colossoma macropomum (Cuvier, 1816), Pygocentrus nattereri Kner, 1858, Cichla temensis Humboldt, 1821, Satanoperca jurupari (Heckel, 1840) and H. scomberoides, Janaucá Lake, state of Amazonas, Brazil (Malta 1983; Thatcher 2006); Pseudoplatystoma punctifer (Castelnau 1855) and Pseudoplatystoma tigrinum (Valenciennes, 1840), Negro and Solimões Rivers, Careiro da Várzea, Manaus, state of Amazonas, Brazil (Lopes et al. 2009); P. nattereri, Serrasalmus maculatus Kner, 1858 and Serrasalmus marginatus Valenciennes, 1837, Upper Paraguay River basin, Northern Pantanal, Cáceres, state of Mato Grosso (Fontana et al. 2012).

Material deposited. 1 voucher: 1 adult female ZUEC-CRU 3515, in ethanol 70%, Pseudoplatystoma corruscans, gills, Paraguay River, Corumbá, Mato Grosso do Sul, Brazil (18°59'53.17"S, 57°36'44.43"O), 0 3 June 2004.

Measurements. Total length (mm) 11.32. Carapace length 6; maximum carapace width 7.5. Carapace posterior sinus length1.62; width 1.72. Cephalothorax length 3.98; anterior width 4.25. Abdome length 2.72; width 2.32. Abdome posterior sinus length 1.8; width 0.3. Eyes diameter (µm) 250 left; 225 right; transverse distance between eyes (µm) 775. First maxillae outer diameter (µm) 1400 left; 1350 right; inner diameter 1075 left; 950 right. Number of support rods in suction cups 46–50; number of sclerites per support rod 8–10.

Remarks. The plate of the second maxilla of A. multicolor in which there are no digitate spines, has a serrated aspect owing to the presence of diminutive spines (Fig. 7), resembling that of A. elongatus. Nevertheless A. elongatus have neither carapace alae nor flagellum on the first two legs (Stekhoven Jr. 1937), structures observed in A. multicolor. In the specimen examined in the present study, were also observed inconspicuous spines, anteriorly in the ventral surface of the carapace, which was not reported for A. elongatus. The thorax of A. multicolor is covered by spines and erect scales and in the second maxillae there are multi-digit scales. The shape of the 8–11 sclerites per rod of the suction cup observed in the present research, is identical to the small, curved transverse lines with a half-moon shape, anteriorly reported (Lemos de Castro 1949; Stekhoven Jr. 1937).