Bidessus perexiguus H. J. Kolbe, 1883

Ramahandrison, Andriamirado Tahina, Rakouth, Bakolimalala & Manuel, Michael, 2022, The aquatic Adephaga of the Makay, central-western Madagascar, with description of two new diving beetle species (Coleoptera, Gyrinidae, Haliplidae, Noteridae, Dytiscidae), ZooKeys 1127, pp. 1-60 : 1

Bidessus perexiguus H. J. Kolbe, 1883

Type locality.

Madagascar, South inner part.

Material examined.

1 ex.: MAK-1A; 4 ♂♂, 1 ex.: MAK-2; 1 ♂: MAK-17; 82 exs.: MAK-18; 4 ♂♂, 25 exs.: MAK-19; 3 exs.: MAK-60; 1 ex.: MAK-61.

Distribution.

Madagascar, widespread ( Guignot 1959-1961; Biström 1985; Bergsten et al. 2020).

Habitat in study area

(Fig. 2B, C ). This species was collected mainly at peripheral sites. Its ecology is similar to that of B. longistriga , and both species were several times sampled in the same habitats, but B. perexiguus has a marked preference for small and very shallow water bodies without vegetation. Notably, this species was particularly abundant in a small muddy ditch only 5 cm deep, shaded under trees, without water flow and with turbid water, trampled by cattle and with no vegetation (MAK-18).

Figures

Figure 2. Representative habitats of aquatic Adephaga in Makay. Sites located in the peripheral area: A large shallow puddle on the sandy bank of the Mangoky River in Beroroa (MAK- 1 C), habitat of Pachynectes costulifer, Yola costipennis B, C shallow, slowly flowing stream in semi-open area, with sandy bottom and high density of green algae (MAK- 2), habitat of Bidessus longistriga, B. perexiguus, Canthydrus concolor, C. flavosignatus, C. guttula, Clypeodytes concivis, C. sp. Ma 3, Cybister cinctus, Hydaticus servillianus, Hydroglyphus geminodes, Hydrovatus acuminatus, H. capnius, H. cruentatus, H. dentatus, H. otiosus, H. parvulus, H. pictulus, H. testudinarius, H. sp. Ma 7, Laccophilus addendus, L. flaveolus, L. pallescens, L. posticus, L. rivulosus, L. seyrigi, Methles sp. Ma 5, Neohydrocoptus seriatus, Pachynectes sp. Ma 1, Philaccolus elongatus, Pseuduvarus sp. Ma 1, Rhantaticus congestus, Uvarus rivulorum. Sites located in inner Makay: D puddle (on the right) on the sandy bank of the Andranomanintsy River (left half of the picture) (MAK- 3), habitat of Copelatus ruficapillus, Hydrovatus acuminatus, Hyphydrus separandus, Laccophilus makay, L. posticus, Madaglymbus fairmairei, Pachynectes sp. Ma 1 E spring on the bank of the Andranomanintsy River (MAK- 4), habitat of Copelatus ruficapillus, Hydroglyphus capitatus, H. geminodes, Hyphydrus separandus, Laccophilus makay, L. posticus, Pachynectes sp. Ma 1 F deep pond above natural dam in the bottom of a canyon (MAK- 5 A), habitat of Africophilus nesiotes, Hyphydrus separandus, L. addendus, Laccophilus insularum, L. makay, Neptosternus oblongus, Pachynectes sp. Ma 1, P. sp. Ma 4 G edge of small shallow stream, in the bottom of a deep strongly embanked canyon, with orange deposit of iron bacteria (MAK- 6), habitat of Copelatus acamas and Laccophilus makay H vertical rock wall with water film and crust of bryophytes and algae, in the bottom of a deep canyon (MAK- 9), habitat of Africophilus bartolozzii I large quiet and shaded pool in forest, along streamlet, with masses of tree roots and bottom of sand, gravel and stones (MAK- 8), habitat of Africophilus bartolozzii, A. nesiotes, Copelatus ruficapillus, Hydaticus sobrinus, Hyphydrus separandus, Laccophilus makay, Pachynectes sp. Ma 1 J (context) K (close-up) Puddle with orange masses of iron bacteria, in stream bed, in the bottom of a deep strongly embanked canyon (MAK- 7), habitat of Copelatus acamas, C. ruficapillus, Laccophilus makay L (context) M (close-up) Small pool with clay-sandy bottom and plant debris, in a small canyon, in gallery forest (MAK- 10), habitat of Copelatus ruficapillus, Hyphydrus separandus, Laccophilus makay, Madaglymbus fairmairei N small shaded pool, with orange masses of iron bacteria, in gallery forest against the wall of a canyon (MAK- 14 A), habitat of Africophilus nesiotes, Copelatus acamas, Hydaticus dorsiger, Hyphydrus separandus, Laccophilus makay, Pachynectes sp. Ma 1, P. sp. Ma 4 O small muddy pond, with sparse vegetation, in open area on the sandy banks of the Menapanda River (MAK- 11 A), habitat of Canthydrus guttula, Copelatus polystrigus, Hydaticus dorsiger, Laccophilus addendus, L. posticus, Neohydrocoptus seriatus P puddle with turbid water and without vegetation, in open area on the sandy banks of the Menapanda River (MAK- 11 - B), habitat of Copelatus polystrigus, C. ruficapillus, Eretes griseus, Hydaticus dorsiger, H. exclamationis, Hyphydrus separandus, Laccophilus addendus, L. posticus, Madaglymbus fairmairei.