Larval morphology of the Palaearctic genera Deronectes Sharp and Scarodytes Gozis (Coleoptera : Dytiscidae : Hydroporinae), with implications for thephylogeny of the Deronectes-group of genera

Description of larval instars of Deronectes depressicollis Rosenhauer 1856, D. lareynii (Fairmaire 1858), D. latus (Stephens 1829), D. aubei (Mulsant 1843), and Scarodytes halensis (Fabricius 1787) is presented including a de tailed chaetotaxic and porotaxic analysis of the cephalic capsule, head app endages, legs, last abdominal segment and urogomphi. A phylogenetic analysi s of 14 genera of the tribe Hydroporini, based on 22 larval characteristics was conducted with Hennig86. Three of the branches of the strict consensus tree have a statistical support greater than 60% according to the Parsimon y Jackknifer. One of the supported clades is Antiporus Sharp + Nebrioporus Regimbart + Neonectes J. Balfour-Browne + Oreodytes Seidlitz + Stictotarsus Zimmermann + Scarodytes Gozis, of which the sister-group is the genus Dero nectes Sharp. Consequently larval characters, in contrast to adult characte rs support the inclusion of Antiporus, Neonectes and Oreodytes in the Deron ectes group of genera. All members of this clade are characterized by: (i) presence of an occipital suture in first instar, (ii) presence of a constri ction at level of occipital suture, (iii) absence of maxillary cardo, and ( iv) insertion of the primary sera MX1 on the maxillary stipes. Scarodytes i s postulated to share a monophyletic origin with Nebrioporus, Stictotarsus, and Antiporus based on (i) the presence of natatory setae on femora, tibia e, and tarsi and (ii) the shape of the urogomphomere 1 which is more than 3 .10 times longer than urogomphomere 2.