A new species of Elpidium (Crustacea, Ostracoda) from phytothelmata in Argentina: description, habitat and geography

KOEN, MARTENS; CAMPOS, R. E.; DÍAZ, ANALÍA

Santa Bárbara, California

Simposio; 18th International Symposium on Ostracoda; 2017

Ostracodacan abound in all types of marine and non-marine water bodies and some species even occur in phytotelmata. Our samples were collected with a pipette fromphytothelmatain 3 different plant species: Aechmeadistichantha, Vrieseafriburgensis(Bromeliacea) and Eryngiumpandanifolium(Apiaceae) in 3areas in the northeast subtropical region of Argentina between 2006 and 2009.Ostracods were dissected and valves stored dry in micropaleontological slides, with dissected soft parts in glycerine in sealed slides. The new species is medium-sized; females are larger than males. Valves have well-developed inner lamellae, and are set with cilia in the posterior part. The surface of the carapace is smooth with few hairs.A1 has5 segments, the first one sub-apically with atiny ventral seta.A2 is sexually dimorphic;the terminal segment of the male carriesa strong serrated claw.Mandibularcoxaehave8 strong teeth. Second and third Mx1-endites carrytwo setae and two spatula-like claws each; the palp is not segmented, tapers and carries two apical setae. The hemipenishas atriangular distal lobe, with a pointed tip and a finger-like projection at the base of the internal margin, a dorsal seta is present near its basis; the Lower Ramusis shaped asa clasping process, the copulatory process is large, a short and pointed dorsal seta is inserted in a rounded base.There are presently eight Elpidiumspecies knownfrom southern Brazil, Jamaica, Puerto Rico, Cuba, Honduras and the south of USA. The new species resembles Elpidiummartensi, E. bromeliarum and E. pintoiin shape and size ofcarapace, butthese specieshave a differenthemipenismorphology.This is the first record of the genus Elpidium in Argentinaand it is the most southernspecies of this genus.