Fig. 1 in Heteropilumnus satriai Yeo, Rahayu and Ng 2004

© 2018 Academia Sinica, Taiwan Open Access On Argentodromas bellanella gen. nov., sp. nov. (Crustacea, Ostracoda) from a Stream in Northeastern Argentina (South America) Analia Díaz1,* and Koen Martens2 1Instituto de Limnología Dr. Raúl A. Ringuelet (CCT-La Plata CONICET), Boulevard 120 y 62, 1900 La Plata, Provincia de Buenos Aires, Argentina 2Royal Belgian Institute of Natural Sciences, Freshwater Biology, Vautierstraat 29, Brussels 1000, Belgium and University of Ghent, Department of Biology, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium. E-mail: [email protected] (Received 5 July 2017; Accepted 21 February 2018; Published 26 March 2018; Communicated by Ryuji Machida) Citation: Díaz A, Martens K. 2018. On Argentodromas bellanella gen. nov., sp. nov. (Crustacea, Ostracoda) from a stream in northeastern Argentina (South America). Zool Stud 57:10. doi:10.6620/ZS.2018.57-10. Analia Díaz and Koen Martens (2018) Argentodromas bellanella gen. nov., sp. nov. is here described from streams in the province of Misiones, in northeastern Argentina. The new genus and species belong to the family Notodromadidae. Most species in the family have morphological adaptations to a hyponeustic mode of life: their carapaces have lip-like protrusions of the valve margins near the mouth and a flat plate-like expansion of the ventral part. The new genus can be distinguished from other genera in the subfamily Notodromadinae based on valve ornamentation (surface of valves covered with polygonal elevations and many pores with setae), the ventral plate-like expansion which is set with 3-4 rows of rounded elevations and bordered with an elevated outer list, eye tubercles softly pronounced, and soft parts features (male prehensile palps moderately asymmetrical and both with elongated first segments, posterior seta of caudal ramus longer than terminal claws and anterior seta present, hemipenis with rounded outer lobe and small rounded inner lobe). For comparative purposes, valves and carapaces of species in three other Notodromadinae genera (Newnhamia, Kennethia, Notodromas) are also illustrated and re-diagnosed. Key words: Notodromadidae, New genus, Morphology, Argentina, Hyponeustic. *Correspondence: E-mail: [email protected]; [email protected] BACKGROUND There are approximately 2000 described species and ca 200 described genera of recent, free-living, non-marine ostracods in the world (Martens et al. 2008; Martens and Savatenalinton 2011). One family, the Cyprididae, comprises about half of all described species (ca 1000) in ca 100 genera. The other families are much less speciose. The family Notodromadidae Kaufmann, 1900, for example, comprises thus far fewer than 40 subjective species. This family is divided into four subfamilies: Centrocypridinae Hartmann and Puri, 1974, Cyproidinae Hartmann, 1963, Notodromadinae Kaufmann, 1900, and Oncocypridinae De Deckker, 1979b. The subfamily Notodromadinae comprises four genera up to now: Gurayacypris Battish, 1987, Notodromas Lilljeborg, 1853, Newnhamia King, 1855 and Kennethia De Deckker, 1979a. Most species in this subfamily have a hyponeustic mode of life and cling upside down to the water film at the surface. They have adapted to this lifestyle using special structures on the ventral side of the valves: lip-like protrusions of the valve margins near the mouth and a flat platelike expansion of the ventral part of the carapace. However, most species also have different shapes Zoological Studies 57: 10 (2018) doi:10.6620/ZS.2018.57-10 1 © 2018 Academia Sinica, Taiwan and external ornamentation, some carapaces have rounded tubercles only, other have pointed tubercles, most have transitional forms (De Deckker 1979a b; George and Martens 2003). Here, we describe a new species and genus of notodromadinid ostracods from a stream in northeastern Argentina. It is only the third species of this subfamily reported from the entire continent and its occurrence in a lotic habitat is exceptional. MATERIALS AND METHODS Moconá Provincial Park is located in the southeast of the province of Misiones in northeastern Argentina. This park is a protected area located near the border with Brazil (27°08'S; 53°53'W) on the banks of the River Uruguay (Fig. 1). Moconá Provincial Park is part of the Biosphere Reserve Yabotí, which has been on the UNESCO list since 1995. Moconá Provincial Park protects one of the most threatened biomes in the world: the Atlantic Forest, which is classified as Threatened and with High Conservation Priority at a Regional Scale. The park is surrounded by two rivers: the Pepirí Yabotí Miní stream and the Uruguay River. The dynamics of waterways inside the park have a strong influence on the entire climate of the park (Bertolini 1999). The terrain is rugged, with elevations ranging from 140 m asl in the Uruguay river banks and Yabotí stream to 349 m in the centre-east of the Park. The banks of the Uruguay River are formed by steep ravines slopes, which end practically at the river itself (Krauczuk 1998). Specimens of the new genus and species were collected on March 2nd, 2010 from Moconá National Park (province of Misiones, Argentina) using an enamelled white spoon and fine mesh strainers. Samples were taken from a small permanent stream, with a maximum depth of 30 cm, running along a path in the middle of the forest. There was no floating vegetation in the stream, but it was surrounded by grass. Comparative material of the genera Notodromas was collected from Belgium, while material of Kennethia and Newnhamia was collected from Australia (see below for details). Ostracods were sorted under a binocular microscope and dissected with valves stored dry in micropaleontological slides and with soft parts in glycerine in sealed slides. Drawings of soft parts were made using the camera lucida and a compound microscope (Olympus, BX51 at Royal Belgian Institute of Natural Sciences (RBINS), Brussels). Valves were illustrated and measured using scanning electron microscopy (Philips XL30 SEM at RBINS, Brussels). Type material of the new genus and species is deposited in the Carcinological Collection of the Museo of La Plata, La Plata (Argentina) (MLP-Cr numbers). References to location of type material of comparative taxa: NHMS = Natural History Museum of Sydney. Abbreviations used in text and figures are as follows: A1 = Antennula, A2 = Antenna, Cp = Carapace, CR = Caudal ramus, CRa = Attachment of caudal ramus, Db = Dorsal branch of CRa, H = Height of valves, L = Length of valves, Lpp = Left prehensile palp, ls = Lateral shield of hemipenis, LV = Left valve, Md = Mandibula, ms = Medial shield of hemipenis, Mx1 = Maxillula, Rpp = Right prehensile palp, RV = Right valve, T1 = First thoracopod, T2 = Second thoracopod, T3 = Third thoracopod, Vb = Ventral branch of CRa, W = Width of carapace, ZO = Zenker organ. Thoracopod terminology follows Broodbakker and Danielopol (1982), for the second antenna the revised model proposed by Martens (1987), and for the second and third thoracopods the nomenclature of Meisch (2000). Higher taxonomy of the Ostracoda follows the synopsis by Horne et al. (2002). Measurements are expressed in μm with numbers of individuals, arithmetic means ± SD shown in parentheses. RESULTS Taxonomy and morphology Order Podocopida Sars, 1866 Superfamily Cypridoidea Baird, 1845 Family Notodromadidae Kaufmann, 1900 Subfamily Notodromadinae Kaufmann, 1900 Argentodromas gen. nov. Díaz and Martens urn: lsid:zoobank.org:pub:F251BB95-49E2-4000-A3D6D18DB76B3ECF Etymology: The first part of the genus name, “Argento”, refers to the country Argentina, the second part refers to the genus Notodromas to which the new genus is closely related. Type species: Argentodromas bellanella gen. nov., sp. nov. (designated here). Diagnosis: Surface of carapace covered with polygonal elevations and many pores with setae. page 2 of 13Zoological Studies 57: 10 (2018) © 2018 Academia Sinica, Taiwan N Fig. 1. Map showing the position of the sampled stream in the Misiones province, Argentina. page 3 of 13Zoological Studies 57: 10 (2018) © 2018 Academia Sinica, Taiwan Large part of ventral surface set with 3-4 rows of rounded elevations and bordered with an elevated outer list. Eye tubercles weakly developed. Prehensile palps moderately asymmetrical and both with first segments elongated. Posterior seta of CR longer than terminal claws, anterior seta present. Hemipenis with elongated and rounded outer lobe and pronounced subrectangular lateral lobe. Differential diagnosis within Notodromadinae: Argentodromas gen. nov. is closely related to Newnhamia, but differs in the shape and structure of the carapace. In Newnhamia the carapace is oval in shape in anterior view and the surface of valves is covered with polygonal elevations and rounded or pointed tubercles. The largest part of the ventral plate-like surface is set with 2-3 rows of rounded elevations and bordered by an elevated outer list. Newnhamia also has clearly pronounced eye tubercles and has a completely different structure of hemipenis (with rounded ms in the new genus). Argentodromas gen. nov. differs from Kennethia, the second Australian genus, because of the lack of the large dorsal expansion on the LV and of the very pronounced external ornamentation in both valves in the latter genus. Argentodromas gen. nov. differs from Notodromas (of which Gurayacypris is most likely a synonym) mainly in the ornamentation of the carapace (almost smooth in Notodromas) and the eye tubercles that are less well-developed in the new genus, as well as in the more strongly asymmetrical prehensile palps and the different hemipenis shape in Notodromas (large main body and only one hook-like expansion - see Meisch 2000, Fig. 99L). Finally, Argentodromas gen. nov. differs from Centrocypris in the morphology of carapace and limbs, especially in the valve ornamentation (at least the type species of Centrocypris has a ventral row of strong spines along the ventral margin in both valves - see Martens et al. 2008, Fig. 1). Argentodromas bellanella gen. nov., sp. nov. Díaz and Martens (Figs. 2-4) Type locality: Moconá National Park, Misiones province, Argentina (27°08'S; 53°53'W) (see Fig. 1). All material collected by Analía R. Díaz on March 2nd, 2010. Material examined: Holotype: a male, with soft parts dissected and store with glycerine in sealed glass slides and valves stored dry in a plastic micropalaeontological slide (MLP-Cr 26923). Allotype: a female, dissected and stored as the male (MLP-Cr 26924). Paratypes: 7 females, 3 males (MLP-Cr 26925). Etymology: The first part of the specific epithet name, “bella”, is an adjective that means beautiful in Italian, the second part “nella” refers to the mother´s name of the first author (AD). Diagnosis: Carapace with weak polygonal ornamentation, rounded in lateral view. Eye cups very weakly developed, recognizable mostly because of absence of ornamentation in these spots. Ventral plate like expansion consisting in 3-4 longitudinal rows of rounded elevations. CR with anterior seta present in both sexes. Hemipenis with two shields, ms distally rounded. Measurements: Males: LV = 619-700 (4, 644 ± 38); H = 408-452 (4, 441 ± 22); RV = 652-690 (4, 660 ± 19); H = 408-428 (4, 426 ± 13). Females: LV = 667-700 (7, 680 ± 14), H = 440-476 (5, 451 ± 17); RV = 650-736 (7, 689 ± 33), H = 490-523 (5, 506 ± 13). Description: Male valves (Figs. 2A-G) smaller than female valves (Figs. 2H-L) but similar in appearance. Carapace sub-triangular in lateral view, anteriorly broadly rounded. In both valves, greatest height situated almost in the middle. Surface of valves covered with rather weak polygonal elevations and many pores with setae. Eye cups weakly developed, to almost absent. Valves sub-equal in dorsal view (Figs. 2C, K) with RV slightly bigger than LV. In ventral view (Figs. 2F, G) large part of the surface set with 3-4 rows of rounded elevations and bordered with an elevated outer list. Eye tubercles softly pronounced. RV (Figs. 2E, J) in inner views, anterior calcified inner lamella broad, posterior one narrower. Selvage largely displaced inwardly in RV (Figs. 2E, J), less so in the LV (Figs. 2D, I). A1 (Fig. 3A) ♀ without sexual dimorphism. First (fused) segment with 2 long ventral setae + 2 short dorsal setae. Second segment with 1 apical seta. Third segment with 2 very short apical setae in both outer and inner side and 2 long apical setae. Fourth segment with 2 long apical setae. 3 long apical setae on fifth segment. Apical (6th) segment with 2 long + 1 short seta and one aesthetasc ya, of c the same length as the setae. A2 (Fig. 3B) ♀. Protopodite with 3 setae. Aestheasc Y long, inserted on first endopodal segment; this segment apically with 5 natatory setae not extending beyond tips of terminal claws, 6th seta shorter. Second endopodal segment with 2 dorsal and 2 ventral apical setae. Third endopodal segment with 3 setae and with G1-claw page 4 of 13Zoological Studies 57: 10 (2018) © 2018 Academia Sinica, Taiwan Fig. 2. Argentodromas bellanella gen. nov., sp. nov. Male (MLP-Cr 26923). (A) RV, ext. view; (B) LV, ext. view; (C) Cp, dorsal view; (D) LV, int. view; (E) RV, int. view; (F) Cp, ventral view; (G) detail of anterior part of (F). Female (MLP-Cr 26924). (H) RV, ext. view; (I) LV, int. view; (J) RV, int. view; (K) Cp, dorsal view; (L) detail of muscle scars. Scale bars: A-F, H-K = 200 µm, G, L = 50 µm (A) (C) (B) (E) (F) (D) (H) (I) (K) (J) (G) (L) page 5 of 13Zoological Studies 57: 10 (2018) © 2018 Academia Sinica, Taiwan Fig. 3. Argentodromas bellanella gen. nov., sp. nov. (A) Female (MLP-Cr 26924) A1; (B) Female (MLP-Cr 26924) A2; (C) Male (MLPCr 26923) A2; (D) Female (MLP-Cr 26924) Md; (E) Male (MLP-Cr 26923) Mx1; (F) Male (MLP-Cr 26923) Respiratory plate Mx1; (G) Female (MLP-Cr 26924) T1. Scale bar: A-G = 100 µm. (A) (D) (F) (G) (E) (C) (B) page 6 of 13Zoological Studies 57: 10 (2018) © 2018 Academia Sinica, Taiwan with a characteristic skewed tip. Aesthetasc (y1 and y2 missing). Apical segment with 1 long claw, 1 short claw-like seta and 1 long aesthetasc (y3) and a seta. A2 (Fig. 3C) ♂ with 2 + 1 setae on the first segment of the protopodite. Subapical segment with aesthetasc y2 ventrally inserted. Apical segment with 1 long and one shorter claw, 1 short aesthetasc and 1 apical seta fused with the aesthetasc. Md (Fig. 3D) ♀ without sexual dimorphism. Coxa with 9 subequal strong teeth. One short smooth seta also present. Mandibular palp with 4 segments. Second segment with 6 plumose ventral “S” setae, two long dorsal setae and three long subapical dorsal seta, this segment also with 4 short apical setae, α-seta smooth and with a relatively broad basis, β-setae plumose and with a swollen basis, γ-seta short and plumose Apical segment with 1 claw-like seta, 2 shorter setae and three smooth long setae of subequal length. Mx (Fig. 3E) ♂ without sexual dimorphism. With terminal segment of palp subquadrate. First palp segment with 3 apical setae, one of them with a characteristic swollen base. Second segment with 5 smooth setae. Third endite with 6 smooth zahnborsten, a group of 4 dorso-apical setae and one smooth seta ventrally inserted. First endite with 2 serrated setae and with two long hirsute setae laterally inserted. Respiratory plate (Fig. 3F) with c 19 rays. T1 (Fig. 3G) ♀. Endite bearing 11 mostly smooth setae of sub-equal length, d-seta strong plumose and b-seta smooth, two a-setae present, with unequal length and not inserted closely together. Female endopodite (palp) with a single, long seta on top. Males with endopods developed in asymmetrical prehensile palps. Rpp (Fig. 4A) with terminal segment banana-shaped with apical sensory organ. First segment longer than the largest width, subapically with 2 short sensory organs. Lpp (Fig. 4B) with terminal segment sickleshape and curved, apically with 1 strong sensory organ. First segment large, subapically with 2 short sensory organs. T2 (Fig. 4C) ♂ . without sexual dimorphism. Without d-setae. First, second and third segment of endopodite with one apical seta. Terminal segment with one large apical claw, flanked by 2 long apical setae. T3 (Fig. 4D) ♂ . without sexual dimorphism. With 3 setae on the first segment and one apical seta on the second segment. Third segment with 1 lateral seta. Terminal segment separated, with 1 long apical claw + 1 seta shorter and a reflexed sub-apical seta. CR (Figs. 4E, F). Relative curved in males, posterior seta long, anterior seta short but always present. Attachment of CR (Fig. 4G) ♂ . Short, X-shaped. Hemipenis (Fig. 4H) with one long and distally rounded protruding medial shield (ms) and one sub-rectangular lateral shield (ls). ZO (Fig. 4I) ♂ . Large and well-developed with 14-15 spinous whorls. Newnhamia fenestrata King, 1855 (Figs. 5A-E) Generic Differential Diagnosis (modified after De Deckker 1979a and George and Martens 2003): Valves rounded in lateral view, externally covered with polygonal elevation and rounded or pointed tubercles (Figs. 5A, B, C, D,). Ventral side of carapace (Fig. 5E) with anterior lip-like expansions of valve margins, near mouth; large part of ventral surface plate-like, set with 2-3 rows of rounded elevations and bordered by an elevated outer list. Each valve with prominent, rounded and opaque antero-dorsal eye-tubercles (Figs. 5C, D). Mandibular palp with 6 plumose internal setae and about 10 apical setae on terminal segment. Maxillula with 6 zahnborsten on third endite and two very large setae near first endite. T2 without d-setae, penultimate segment divided, terminal segment with one long claw and two subapical setae, the latter unusually long in at least some species. T3 with terminal segment separate from penultimate segment. Caudal ramus with distal seta. Type locality and type material: Swamp 2 km east of Princetown, near Port Campbell, Victoria, Australia, 38°41'0"S 142°09'0"E: Neotypes ( ♂ , ♀), NHMS - Xe 19841, 19842. Material examined here: several dozen specimens, collected by P. De Deckker and K. Martens from a pond near Good Hope resort, near Canberra (ACT/NSW - coordinates.: 35°6'26"S 148°51'670"E) on 25.03.2013. Kennethia cristata De Deckker, 1979a (Figs. 5F-K) Generic Differential Diagnosis (modified after De Deckker 1979a): Carapace with polygonal elevations (Figs. 5F, G, I, L), eye tubercles separate and well-developed. Carapace in dorsal page 7 of 13Zoological Studies 57: 10 (2018) © 2018 Academia Sinica, Taiwan Fig. 4. Argentodromas bellanella gen. nov., sp. nov. (A) Male (MLP-Cr 26923) Rpp; (B) Male (MLP-Cr 26923) Lpp; (C) Male (MLPCr 26923) T2; (D) Male (MLP-Cr 26923) T3; (E) Female (MLP-Cr 26924) CR; (F) Male (MLP-Cr 26923) CR; (G) Male (MLP-Cr 26923) CRa; (H) Male (MLP-Cr 26923) Hemipenis; (I) Male (MLP-Cr 26923) ZO. Scale bars: A-H = 100 µm, I = 50 µm. (A) (C) (D) (G) (E) (F) (H) (B) (I) page 8 of 13Zoological Studies 57: 10 (2018) © 2018 Academia Sinica, Taiwan Fig. 5. Newnhamia fenestrata (A-E) and Kennethia cristata (F-L) Newnhamia fenestrata. Females. (A) LV, int. view; (B) RV, int. view; (C) Cp, dorsal view; (D) Cp, left lateral view (E); Cp, ventral view. Kennethia cristata. Females. (F) Cp, right lateral view; (G) Cp, left lateral view; (H) Detail of muscle scars; (I) Cp, dorsal view; (J) LV, int. view; (K) RV, int. view; (L) Cp, ventral view. Scale bars: A-G, I-K = 250 µm, H = 50 µm. (A) (D) (G) (J) (C) (E) (I) (L) (B) (F) (H) (K) page 9 of 13Zoological Studies 57: 10 (2018)