Zootaxa 4845 (2): 253–263 ISSN 1175-5326 (print edition) https://www.mapress.com/j/zt/ Article ZOOTAXA Copyright © 2020 Magnolia Press ISSN 1175-5334 (online edition) https://doi.org/10.11646/zootaxa.4845.2.6 http://zoobank.org/urn:lsid:zoobank.org:pub:D6BDC2D9-83F3-4DCD-91D9-94B38E863C2A Madangella koumacensis, a new species of palaemonid shrimps (Decapoda: Palaemonidae) from New Caledonia PAVLÍNA FROLOVÁ & ZDENĚK ĎURIŠ* Department of Biology and Ecology, and Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Chittus- siho 10, Ostrava, CZ-710 00, Czech Republic. [email protected]; https://orcid.org/0000-0002-9108-0805 * [email protected]; https://orcid.org/0000-0003-1701-6562 *Corresponding author Abstract A second species of the recently established genus Madangella Frolová & Ďuriš is described from New Caledonia. Although the single available specimen lacks both second pereiopods, the new species distinctly differs from the only other representative of the genus, M. altirostris Frolová & Ďuriš, 2018 from Papua New Guinea, and can be easily distinguished from the latter by the more elongate and distally tapering rostrum, two subterminal ventral rostral teeth, the carpus of the first pereiopod being subequal to the merus length, and the sixth pleomere being short and stout, distinctly less than 2 times longer than deep. The examined specimen was confirmed as representative of a species separate from M. altirostris also by molecular comparisons of the 16S rRNA and COI mtDNA gene markers. The genus Madangella thus currently consists of two southwestern Pacific species. Key words: Caridea, Crustacea, Indo-West Pacific, taxonomy Introduction The most species-rich family of the caridean shrimps, Palaemonidae Rafinesque, 1815, contains over 1000 de- scribed species, the majority of which dwell in freshwater or live in symbioses with marine invertebrates of different phyla. The marine species chiefly occur in tropical and subtropical latitudes in shallow waters, with their highest diversity in the Indo-West Pacific area. This family comprises several partial monophyletic assemblages with yet unresolved mutual relations (De Grave et al., 2015; Chow et al., 2020). One of those is repeatedly recovered in re- cent molecular studies (Kou et al., 2013, 2015; De Grave et al., 2015; Gan et al., 2015a,b; Horká et al., 2016, 2018; Head et al., 2018; Chow et al., 2020) as separated from the main diversity of almost exclusively symbiotic taxa of the previous palaemonid subfamily Pontoniinae Kingsley, 1879. It is represented by predominantly free-living species of the most speciose genera Cuapetes Clark, 1919, and Palaemonella Dana, 1852, but contains also some symbiotic species, or even genera, associated mainly with cnidarians, e.g. Harpilius Dana, 1852, Ischnopontonia Bruce, 1966, Philarius Holthuis, 1952, or Vir Holthuis, 1952. This group, systematically not defined (De Grave et al., 2015), has been referred to as the ‘basal clade’ (Gan et al., 2015a,b), ‘primitive group’ (Kou et al., 2015), or the ‘basally separated clade’ (Horká et al., 2016, 2018), in relation to other Pontoniinae, or indicated as the ‘CP com- plex’ (i.e. Cuapetes-Palaemonella complex of palaemonid genera) by Frolová & Ďuriš (2018), and most recently annotated as the ‘Pon-I clade’ by Chow et al. (2020), i.e. one of two clades of the ‘Pontoniinae’ in their phylogenetic analysis. Based on this phylogenetic relationship and the presence of plesiomorphic morphological characters (e.g. the mandibular palp in some, or a finger-like median process on the fourth thoracic sternite, and simple ambulatory dactyli in all taxa, see Kou et al., 2015; Frolová & Ďuriš, 2018), this assemblage now contains 11 genera. The last established one is Madangella Frolová & Ďuriš, 2018. Until now, the genus Madangella has comprised just a single species, M. altirostris Frolová & Ďuriš, 2018 from the Bismarck Sea, Papua New Guinea. Recently, a single specimen of an undescribed species closely related to M. Accepted by J. Goy: 7 Aug. 2020; published: 2 Sept. 2020 253 altirostris was collected during the Koumac 2.3 expedition to New Caledonia. It was caught by dredging in an off- shore shallow-water marine habitat, similarly as in the type species from Papua New Guinea. The new species is described and illustrated in the present study. GenBank numbers of obtained sequences of two mitochondrial gene markers, 16S rRNA and COI mtDNA, are provided. Material and Methods Collecting and identification. The specimen of the new species was collected during the Expedition Koumac 2019 in New Caledonia by dredging in shallow waters, preserved in 80% ethanol and deposited in the Muséum national d’Histoire naturelle (MNHN), Paris. The identification was performed by stereomicroscopic examination. The hand drawn illustrations were made with the aid of a drawing tube mounted on a WILD stereomicroscope and redrawn from scanned draft sketches via the PhotoShop software on the Wacom Cintiq graphics tablet. DNA extraction, PCR and sequencing. Total DNA was extracted from the abdominal muscle tissue by extrac- tion kit DNeasy Blood and Tissue Kit (QIAGEN, Germany), following the manufacturer’s protocols. Two partial mitochondrial genes were amplified by polymerase chain reaction (PCR): mitochondrial 16S ribosomal RNA (16S rRNA) using primer pair AR/1472 (Palumbi, 1991; Crandall & Fitzpatric, 1996) and cytochrome c oxidase subunit mitochondrial DNA (COI mtDNA) using primer pair CrustF1/HCO2198 (Costa et al., 2007; Folmer et al., 1994). PCR were performed in 20 μl volume contains DNA template, 10 μM forward and reverse primers for each gene, 0.5 U/μl MyTaq DNA polymerase, 10 x MyTaq Red Polymerase buffer and distilled water. The thermal cycling profiles conformed to the following parameters: 16S – according to the protocol of Bracken-Grissom et al. (2014); COI – initial denaturation for 5 min at 94ºC followed by 40 cycles of 30 s at 94ºC, 30 s at 48ºC, 1 min at 72ºC and a final extension of 5 min. The amplified DNA was purified using Gel/PCR DNA Fragments Extraction Kit (GE- NAID, Taiwan). Sequencing reactions were performed using ABI3730XL DNA Sequencer by Macrogen, Inc. (Am- sterdam). The obtained sequences of genes 16S and COI were submitted to GenBank and their accession numbers are MT819437 and MT816395, respectively. These sequences were used for molecular comparison (p-distances) of the new species with the related M. altirostris from Papua New Guinea (GenBank accession numbers MH286366 for COI, and MH286363 for 16S; Frolová & Ďuriš, 2018). Systematics Family Palaemonidae Rafinesque, 1815 Genus Madangella Frolová & Ďuriš, 2018 Diagnosis (modified from original report). Small, slender shrimp, body subcylindrical, smooth. Carapace with epigastric tooth, with antennal and hepatic teeth, without supraorbital teeth. Rostrum compressed, short and deep, not reaching distal end of antennular peduncle, dorsally dentate, with 1–2 subapical ventral teeth. Fourth thoracic sternite with finger-like median process. Eyes large, cornea broader than stalk, eyestalk short, stout; accessory pigment spot indistinct. Antennula with stylocerite acutely produced distolaterally, statocyst large, rounded; distal margin with small lateral tooth terminal or subterminal and rounded or obsolete lobe medially; with ventromedial tooth; intermediate and distal peduncular segments elongate; outer flagellum biramous, fused part slender, long. Antennal basicerite with small lateral tooth, scaphocerite far overreaching antennular peduncle, elongate, with dis- tolateral tooth subequal to convex distal margin of lamella; carpocerite short. Mandible with well-developed incisor and molar processes, palp absent. Maxillula with normal palp and endites. Basal endite of maxilla bilobed, palp elongate, scaphognathite ovoid. Maxillipeds normal, with well-developed exopods and epipods; endites on first maxilliped separated by distinct incision, palp setose, caridean lobe small, epipod broadly triangular; second max- illiped with epipod well developed, simple, without podobranch; third maxilliped with merus laterally spinulate, ischium, basis and coxa feebly separated, coxa with rounded lateral lobe, arthrobranch absent or single, rudimentary. First pereiopods slender, fingers simple, subequal or longer than palm, carpus longer than chela, and longer or sub- equal to merus, coxa with distoventral setose lobe. Second pereiopods feeble, symmetrical, slender, similar to first 254 · Zootaxa 4845 (2) © 2020 Magnolia Press FROLOVÁ & ĎURIŠ pereiopods, overreaching latter by chela and distal carpus; fingers simple, longer than palm, carpus almost twice as long as chela or merus. Ambulatory legs long and slender, dactylus very slender, simple, slightly curved, as long as or longer than half of propodus length, unguis acute; propodus slender, distoventral spines small or lacking. Five pleurobranchs present on body wall above bases of pereiopods. Pleomeres with pleurae I–IV rounded; fifth postero- laterally rounded or acute, sixth pleonal segment elongate or stout, as long as or longer than telson. Telson elongate, with 2 pairs of minute dorsolateral spinules; posterior margin subtriangular, with 3 pairs of spiniform setae, lateral spines minute, intermediate longest. Uropodal protopod unarmed, rami overreaching telson; exopod with minute distolateral tooth and longer movable spine medially, diaeresis indistinct or distinct. Madangella koumacensis sp. n. (Figs 1–5) Type material. Holotype: ovigerous female MNHN-IU-2019-2713, Expedition