Atopobathynella paraoperculata n. sp. (Syncarida, Bathynellacea, Parabathynellidae) from the River Krishna, southeastern India

Abstract

To date, the genus Atopobathynella Schminke, 1973, is known by 11 species in the world. Here, Atopobathynella paraoperculata n. sp., the second species of this genus from India, is described from the interstitial hyporheic zone of the River Krishna in Andhra Pradesh state. It has closest similarity with its Indian congener, Atopobathynella operculata Ranga Reddy, Drewes & Schminke, 2008, as borne out by the fusion of the inner flagellum of the antennule with the first segment of the outer flagellum, the presence of a seta on the subdistal outer surface of the uropodal sympod; the antennal organ consists exclusively of two massive lobes; the antenna has three instead of four armature elements; the proximal segment of the maxillule has two instead of four distinct claws; the uropodal sympod has an inhomonomous row of spines; and the anal operculum is massive. However, the new species can be easily separated from A. operculata by several other criteria such as the labrum without vs. with tubular pores; the second endopodal segment of Th I has two setae vs. one seta; the uropodal sympod has four vs. eight spines; the uropodal endopod has two weak setae vs. one normal seta; the pleotelson is unarmed vs. armed; and the anal operculum has a subacute vs. a rounded tip. Further, based on the novelties observed in the two Indian congeners, some of the principal generic characters and their states are briefly discussed, and also some ecological notes are added. ZUSAMMENFASSUNGBisher sind 11 Arten der Gattung Atopobathynella Schminke, 1973 auf der Erde bekannt. Hier wird Atopobathynella paraoperculata n. sp., der zweite Vertreter der Gattung in Indien, aus dem hyporheischen Interstitial des Flusses Krishna im Bundesstaat Andhra Pradesh beschrieben. Die neue Art steht der zweiten indischen Art, Atopobathynella operculata, am nächsten, wie folgende Merkmale erweisen: die Verschmelzung des inneren Flagellums der Antennula mit dem ersten Glied des äußeren Flagellums, die Borste auf der Außenseite des Uropoden-Sympoditen, das Antennalorgan, das nur aus zwei kräftigen Loben besteht, die Antenna mit nur 3 statt 4 Borstenelementen, der proximale Endit der Maxillula mit zwei statt vier Klauen, der UropodenSympodit mit einer inhomonomen Dornenreihe, das kräftige Analoperculum. Andererseits gibt es mehrere Merkmale, in denen sich die neue Art von A. operculata unterscheidet: das Labrum