Helophorus Explained

Helophorus is the only genus in the beetle family Helophoridae (traditionally included within Hydrophilidae as the subfamily Helophorinae) within the Hydrophiloidea. They are small insects, found mainly in the Holarctic region (150 occur in Palearctic and 41 species in North America), but two or three species also live in the Afrotropical region, Central America and one in the Indomalayan region (northern India).[1] [2]

Characteristics

Length about 2–9 mm. Body elongate with outline more or less interrupted between pronotum and elytra. On pronotum they have granulate sculpture and unique pattern of 7 longitudinal grooves. Ventral surface is with fine microsculpture, pubescent. Larvae are with long 3 segmented urogomphi and simple (non lobate) 8th tergum. They have four-segmented legs and a 10 segmented abdomen (with the 10th segment being a bit reduced).[3]

Ecology

The majority of Helophorus species adults are aquatic live on the periphery of rivers and streams as well as stagnant bodies of water or pools, though a number are also terrestrial. Adults generally feed on decaying plant material, though some are known to feed on living plant tissue, with several species noted as pests of turnips. The larvae are terrestrial and are predominantly carnivores, though in some species are herviorous, and are pests of turnips, rutabaga, and wheat.[4]

Systematics and evolution

Helophoridae belong to the superfamily Hydrophiloidea, and may be the sister taxon of Hydrochidae,[5] or a clade comprising Hydrochidae, Hydrophilidae and Spercheidae or Georissidae and Epimetopidae.[6] Earlier systems included all of these families in the family Hydrophilidae. The genus is divided into many subgenera (Atracthelophorus, Cyphelophorus, Empleurus, Eutrichelophorus, Gephelophorus, Helophorus, Orphelophorus, Rhopalohelophorus and Transithelophorus).The oldest fossils of Helophorus are from the Late Jurassic of Asia, with the major clades of extant Helophorus likely diverging from each other during the Early Cretaceous.[7]

There are about 180 living species, including:

Notes and References

  1. Angus R.B., 1992. Insecta: Coleoptera: Hydrophilidae: Helophorinae, pp. XI + 144. In: Schwoerbel J. & Zwick P. (eds.), Süsswasserfauna von Mitteleuropa, Band 20/10-2.Spektrum Akademischer Verlag, Heidelberg, Berlin
  2. Mart, A, Erman, O., A Study on Helophorus Fabricius, 1775 (Coleoptera, Hydrophilidae) Species. Turk. J. Zool. 25 (2001) 35-40
  3. M.Hansen. Phylogeny and classification of the staphyliniform beetle families (Coleoptera). Biologiske Skrifter 48, Copenhagen, 1997
  4. "12. Hydrophiloidea Latreille, 1802". Volume 1 Coleoptera, Beetles. Morphology and Systematics, edited by Rolf G. Beutel and Richard A.B. Leschen, Berlin, Boston: De Gruyter, 2016, pp. 231-272.
  5. E.Anton, R.G.Beutel, On the Head Morphology and Systematic Position of Helophorus (Coleoptera: Hydrophiloidea: Helophoridae.)Zoologischer Anzeiger, Vol.242, 4, 2004
  6. M.S.Caterino et al. On the constitution and phylogeny of Staphyliniformia (Insecta: Coleoptera), Molecular Phylogenetics and Evolution, Vol.34 - 3, 2005
  7. Fikáček . Martin . Prokin . Alexander . Angus . Robert B. . Ponomarenko . Alexander . Yue . Yanli . Ren . Dong . Prokop . Jakub . July 2012 . Phylogeny and the fossil record of the Helophoridae reveal Jurassic origin of extant hydrophiloid lineages (Coleoptera: Polyphaga) . Systematic Entomology . en . 37 . 3 . 420–447 . 10.1111/j.1365-3113.2012.00630.x. 2012SysEn..37..420F . 86311781 .

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