Research Article |
Corresponding author: Damià Jaume ( damiajaume@imedea.uib-csic.es ) Academic editor: Danielle Defaye
© 2017 Miguel Alonso, Edinaldo N. dos Santos-Silva, Damià Jaume.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Alonso M, dos Santos-Silva EN, Jaume D (2017) A new species of Notodiaptomus from the Ecuadorian Andes (Copepoda, Calanoida, Diaptomidae). ZooKeys 697: 59-71. https://doi.org/10.3897/zookeys.697.12204
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Notodiaptomus cannarensis sp. n. is described from a reservoir on the Amazonian slope of the Ecuadorian Andes. The new species is unique among diaptomid calanoid copepods in the display of hypertrophied, symmetrical wing-like extensions at each side of the female composite genital somite. Furthermore, it displays a female urosome reduced to only two somites due to the incorporation of abdominal somites III and IV to the composite genital double-somite, and a male right fifth leg with the outer spine of second exopodal segment recurved and implanted proximally on margin. It differs from any other Notodiaptomus in the display of a large rectangular lamella on proximal segment of exopod of male right fifth leg. The species is currently known only from Mazar reservoir, a eutrophic water body placed above 2127 m a.s.l. on the River Paute (Cañar Province; southern Ecuador), where it is the most common crustacean in the water column.
Crustacea , Ecuador, reservoirs, South America, zooplankton
The inland waters of the Neotropical region harbour representatives of at least three different calanoid copepod families, viz.Centropagidae Giesbrecht, 1892, Pseudodiaptomidae G.O. Sars, 1902, and Diaptomidae Baird, 1850. The Centropagidae (22 species reported thus far;
The copepods were collected in the water column of Mazar reservoir using a plankton net of 60 µm mesh size hauled from 25 m depth. Sampling was performed in the framework of the project “Comprensión de los Procesos Hidroecológicos como base para la Estimación del Caudal Ecológico en las Cuencas del Jubones y Paute”, sponsored by the Secretaría Nacional de Educación Superior, Ciencia, Tecnología e Innovación of the Government of the Republic of Ecuador. Water in the reservoir is poorly mineralized (56-62 µS/cm) and turbid due to presence of phytoplankton (Secchi Disk depth 1.4 m), in accord to its eutrophic condition. Material was fixed in situ with formalin and dissected in glycerine on an excavated slide. Drawings were prepared with a camera lucida attached to an Olympus BH-2 microscope equipped with phase contrast. Terminology used in descriptions follows
Mazar reservoir (River Paute, Cañar Province, southern Ecuador). Coordinates 2°35’53.08”S; 78°37’32.16”W. Altitude: 2127 m a.s.l. Holotype: male 1.2 mm long, preserved in formalin vial. Paratypes: Ten males and ten females, preserved in formalin vial. Holotype and paratypes registered under same registration number [
Female urosome reduced to only two somites due to incorporation of abdominal somites III and IV into composite genital double-somite; resulting composite somite with symmetrical, hypertrophied wing-like (in dorsal aspect) extensions at each side. Male right fifth leg with outer spine of second exopodal segment recurved and implanted proximally on margin.
Species name refers to the Ecuadorian province where it was found (Cañar Province; southern Ecuador).
Known only from Mazar reservoir, located on the River Paute (Amazon Basin, Cañar Province, southern Ecuador), 2127 m a.s.l.
Body up to 1.4 mm long. Prosome 5-segmented, comprising cephalosome plus first to third free pedigerous somites, and partially-fused fourth and fifth pedigerous somites (Fig.
Notodiaptomus cannarensis sp. n., adult female. A anterior portion of prosome showing rostrum, insertion of antennules, labrum and paragnaths, ventral B last pedigerous somite plus urosome and caudal rami, dorsal C same, ventral D same, left lateral E inset of genital aperture F right antennule, ventral G inset of terminal segments of latter H fifth legs, posterior.
Antennules (Fig.
Antenna (Fig.
Labrum (Fig.
Mandible coxal gnathobase (Fig.
Maxillule (Fig.
Maxilla (Fig.
Maxilliped (Fig.
Swimming legs 1-4 (Fig.
Coxa | Basis | Exopod | Endopod | |
---|---|---|---|---|
Leg 1 | 0-1 | 0-0 | I-1; 0-1; I,I,4 | 0-1; 1,2,3 |
Legs 2 & 3 | 0-1 | 0-0 | I-1; I-1; I,I,5 | 0-1; 0-2; 2,2,3 |
Leg 4 | 0-1 | 1-0 | I-1; I-1; I,I,5 | 0-1; 0-2; 2,2,3 |
Fifth legs (Fig.
Body up to 1.22 mm long. Differing from female in fifth legs, modified right antennule, asymmetrical epimeral plates of composite last prosomal somite, and segmentation and asymmetry of urosome, including caudal rami. Thus, the extensions of the epimeral plates corresponding to the partially fused fourth and fifth pedigerous somites are directed laterally instead of backwards, with the pointed processes present on each side less marked than in the female (Fig.
Notodiaptomus cannarensis sp. n., adult male. A last pedigerous somite plus urosome and caudal rami, dorsal B inset of last pedigerous somite with fifth legs attached plus urosome and caudal rami, right lateral aspect C fifth legs, posterior D and E different aspects of left fifth leg rami F inset of right fifth leg endopod.
Right antennule (Fig.
Fifth leg (Fig.
The new species described herein corresponds in almost all respects to the re-diagnosis of Notodiaptomus Kiefer, 1936, as presented by
The new taxon can be distinguished from any other representative of the genus by its female composite genital somite, which displays a hypertrophied, wing-like (in dorsal aspect) extension at each side; no other calanoid copepod is known to display such hypertrophied symmetrical extensions, although two Neotropical taxa, viz. Tumeodiaptomus Dussart, 1979, and some members of Rhacodiaptomus Kiefer, 1936 (e.g. Rhacodiaptomus besti Santos-Silva & Robertson, 1993, and in a lesser extent R. insolitus (Wright, 1927) or R. retroflexus Brandorff, 1973), show somewhat similar structures but with only one of the two wings hypertrophied (see
Apart from these unique features, the new species shows a series of character states in the armature of several limbs that differ from the condition found in the type-species of the genus N. deitersi (Poppe, 1891) as redescribed by
The new species differs also from any other Notodiaptomus in the display of a large rectangular lamella on proximal segment of exopod of male right fifth leg.
This study has been supported by a grant PROMETEO from the Secretaría de Educación Superior, Ciencia, Tecnología e Innovación of Ecuador, to the first author. We are grateful to Verónica Ordóñez, who first collected the new species and kindly offered us her material for study.