Larval morphology of Yateberosus, a New Caledonian endemic subgenus of Laccobius (Coleoptera: Hydrophilidae), with notes on 'Berosus-like' larvae in Hydrophiloidea

The morphology and head chaetotaxy of the second and third instar larvae of Laccobius (Yateberosus) sp. are described based on specimens collected in New Caledonia. The larvae agree with those of other subgenera of Laccobius Erichson, 1837 in most morphological characters including the morphology of head and mouthparts and the head chaetotaxy, which undoubtedly supports its assignment to Laccobius (Yateberosus). It differs from other Laccobius in the closed spiracular system, reduced spiracular atrium and long abdominal tracheal gills, in which they resemble the larvae of Berosus Leach, 1817. We demonstrate that the 'Berosus-like' larval morphology evolved at least four times independently in Hydrophiloidea, and briefly discuss the possible reasons for it.