Notodiaptomus coniferoides (Wright, 1927)

Perbiche-Neves, Gilmar, Boxshall, Geoffrey Allan, Previattelli, Daniel, Nogueira, Marcos Gomes & da Rocha, Carlos Eduardo Falavigna, 2015, Identification guide to some Diaptomid species (Crustacea, Copepoda, Calanoida, Diaptomidae) of " de la Plata " River Basin (South America), ZooKeys 497, pp. 1-111 : 33

Taxon classification Animalia Calanoida Diaptomidae

Notodiaptomus coniferoides (Wright, 1927) Figs 39, 40, 41, 42, 43

Diaptomus conferoides Wright, 1927

Diaptomus lobifer Pesta, 1927

Diagnosis.

Adult male, body length 1051 µm. Ped2, Ped3 and Ped4 ornamented with spinules near posterior margin (Fig. 40A). Ur3 to Ur5 lacking ventral spinulation (Fig. 40B). Segment 13 of A1R with strong spinous process (Fig. 39B) reaching distal margin of segment 14; segment 15 with short spinous process slightly larger than spinous process on segment 16 (Fig. 40C, G, H). Lateral spine of right Exp2P5 short, inserted on small lobe-like protuberance (Figs 39A, 40D, F); spine slightly curved towards terminal claw. Terminal claw smooth and relatively long (Fig. 40E) compared to other species, approximately twice length of internal margin of right Exp2P5.

Adult female, body length 1411 µm. Suture between Ped4 and Ped5 incomplete; conical dorsal process present on Ped4 (Figs 41A, 42A, B); lateral wings symmetrical, with two pairs of sensillae, larger pair on apex of each wing (Fig. 42B), each about twice as long as wide; inner pair of sensillae located dorsally near internal margin of each wing, each about as long as wide. GS asymmetrical, approximately 1.7/1.8 times longer than wide; anterior part slightly dilated, each anterior swelling with apical sensilla; left sensilla distinctly curved posteriorly, right sensilla aligned perpendicular to longitudinal body axis (Fig. 41A). P5 symmetrical with small conical process at outer distal corner of Cx bearing short, robust and triangular sensilla (Fig. 41B). BspP5 with external seta almost reaching middle of external margin of Exp1P5. EnpP5 2-segmented, almost reaching end of inner margin of Exp1P5; EnpP5 with 2 strong unequal apical spines. ExpP5 3-segmented; lateral spine of Exp2P5 almost as long as external margin of Exp3P5; internal seta on Exp3P5 about 3.5 times longer than external seta; internal seta reaching middle of terminal claw.

Remarks.

The specimens illustrated here were collected in the upper Paraguay River. This is the only calanoid species that was found throughout the Paraguay basin (Fig. 43). Frutos et al. (2006) previously reported this species from along the Paraguay River. We did not find it in the basin of the Paraná River or the Uruguay River but it was previously observed in the middle section of the Paraná River by Dussart and Frutos (1985). Santos-Silva (2008) mentioned a record from the Itaipu Reservoir in the upper Paraná River basin, and other reports indicate its presence in the lower Paraná River, near the delta (e.g. Ringuelet 1958). The type locality of this species is in the Amazon ( Wright 1927).

This species has a wide distribution in rivers and associated systems like marginal ponds, but it is not typically recorded in reservoirs. This species is easily distinguishable by the position of the lateral spine on a lobe on the coxa of P5 and by the length of spinous processes on segments 13 and 15 of the male A1R. Some studies have reported this species under the name Notodiaptomus coniferoide (sic.) (see Matsumura-Tundisi 1986), but the name presented in the original description by Wright (1927) is Notodiaptomus coniferoides .

Cicchino et al. (2001) described a new species from the Amazon region, which they named Notodiaptomus simmilimus , and its etymology alluded to its close resemblance with Notodiaptomus coniferoides . Comparison of the specimens described here with the observations made by previous authors revealed some distinctive features. However, we consider that the specimens from Venezuela identified as Notodiaptomus coniferoides by Dussart (1984) are in fact Notodiaptomus simmilimus , based on the differences in the proportions of BspP5 and the size of the modified seta on segment 13 of A1R. Dussart (1984) and Cicchino et al. (2001) did not refer to differences in the size of the modified seta on this segment, which tends to be smaller in Notodiaptomus simmilimus than in Notodiaptomus coniferoides . In the Amazonian specimens of Notodiaptomus coniferoides , the modified seta reaches the end of segment 14, according to the original description ( Wright 1927), whereas in Notodiaptomus simmilimus it only extends to the middle of this segment.

We recommend a thorough comparative analysis of specimens of Notodiaptomus coniferoides found in the south of Brazil and in the lower Parana River. Comparison of our Notodiaptomus coniferoides with Amazonian specimens indicates that the material described in the present study was relatively smaller and we consider it is necessary to confirm the identity and status of Notodiaptomus coniferoides in de la Plata River Basin.