Freshwater Macroinvertebrates in Hong Kong

Psephenoides spp.

Family: Psephenidae (subfamily: Psephenoidinae)*

Habitat: Found clinging to underside stone surface in clean running streams, mostly near stream banks.
General appearance: Body flattened broadly oval with combined thoracic & abdominal segments; head and legs hidden when viewed from above; elongated abdominal paratergites VII & presence of anal gills.
Life history: Studies (Dudgeon, 1995) showed this species is in asynchronous growth with continuous recruitment compared to bivoltine in Mataeopsephus chinensis (formerly Sinopsepheus chinensis).

* Psephenidae is classified into five subfamilies: Psepheninae, Eubrianacinae, Psephenoidinae, Eubriinae & Afroeubriinae.
Characteristics in Psephenoidinae:
- abdominal segments VIII & IX form a spindle shaped structure and enclosed by the abdominal segments VII.
- anal gills could protrude from an operculate cavity of abdominal segments VIII & IX.

There are two kinds of morphospecies shown
Comparison
Comparison

The close-up for left species
Fullview
In dorso posterior view
In dorso-anterior view
Ventral view
Ventral view
Ventral view

The close-up for right species
Fullview
In dorso-anterior view
In dorso posterior view
Ventral view
Ventral view

 

Reference:

Dudgeon, D. (1995).  Life histories, secondary production and microdistribution of Psephenidae (Coleoptera: Insecta) from a tropical forest stream.  Journal of Zoology, London 236: 465-481.

Lee, C.F., Sato, M., Shepard, W.D., Jach, M.A. (2007) Phylogeny of Psephenidae (Coleoptera: Byrrhoidea) based on larval, pupal and adult characters The Royal Entomological Society, Systematic Entomology 32: 502–538.

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