Diphyllostoma
| Diphyllostoma | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Diphyllostomatidae | ||||||||||||
| Holloway , 1972 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Diphyllostoma | ||||||||||||
| Fall , 1901 |
Diphyllostoma is the only genus of the family Diphyllostomatidae from the beetle superfamily of the Scarabaeoidea .
features
Beetle
The beetles are 5.0 to 9.0 millimeters in length. Their body is elongated and oval and is brown to reddish brown in color. The head has mouthparts pointing forward and not pointing downward. The ten-membered antennae, which are club-shaped at the end, are straight and not kneeled. They are covered with fine toment. The mandibles are strongly developed and either angular or rounded at the tip. They protrude over the apex of the labrum . The maxillary and labial palps are four-limbed. The pronotum is slightly convex and has no tubercles, grooves, furrows or processes. Its base is narrower than that of the upper wing . The parabolic shield ( scutellum ) is exposed. The hips ( coxes ) of the front legs are almost conical. The hips of the middle legs are almost adjacent to each other. The rails ( tibia ) of the front legs are serrated on the outer edge. The extended spur is missing at its apex. The rails of the middle and rear legs have grooves and two spurs at their apices. The simple claws are all the same size. To the tarsi a is Empodium formed, which extends with its tip up to the fifth Tarsomer carries two bristles. The slightly convex wings are elongated and hide the pygidium . They are provided with slightly indented rows of dots. The males are fully capable of flight, the females have receded wings and cannot fly. The abdomen has seven visible sternites , on which there are functional tracheal openings in the pleural membranes . The genitals of the males have a triple lobe.
The following autapomorphies differentiate the species from the other families of the Scarabaeoidea: the abdomen has seven ventrites , the hind wings have a single, free-standing branch of the second anal artery, the middle and rear rails have an oblique crest of small thorns and a hem on the outside of thorns at the apex, the tarsomeres, especially the first and fifth, are relatively long, the trochantin at the base of the forelegs is exposed, and the males have a forward extension on the basal part of the penis.
Distribution and way of life
The three previously known species of Diphyllostoma are endemic to the west coast of California . The beetle's way of life has only been poorly researched. The larvae are so far completely unknown, but it is believed that they live in the ground.
Taxonomy and systematics
Originally, the genus was assigned to the Schrötern (Lucanidae) in 1901 by Henry Clinton Fall , whose assignment lasted for a long time. It was not until 1972 that Beverley Anne Holloway put the group into a family of their own. She suspected that they would be closely related to the dung beetle (Geotrupidae), but Browne and Scholtz suspect the Schröter as the closest related sister taxon . The following three types are known to date:
- Diphyllostoma fimbriata case , 1901
- Diphyllostoma linsleyi case , 1932
- Diphyllostoma nigricollis case , 1901
supporting documents
Individual evidence
- ↑ a b c d Rolf G. Beutel, Richard AB Leschen: Handbuch der Zoologie - Coleoptera, Beetles, Volume 1: Morphology and Systematics (Archostemata, Adephaga, Myxophaga, Polyphaga partim) . 1st edition. de Gruyter , 2005, ISBN 3-11-017130-9 , p. 376 (English).
literature
- Rolf G. Beutel, Richard AB Leschen: Handbuch der Zoologie - Coleoptera, Beetles, Volume 1: Morphology and Systematics (Archostemata, Adephaga, Myxophaga, Polyphaga partim) . 1st edition. de Gruyter , 2005, ISBN 3-11-017130-9 (English).