Tag Archives: Bembidion

Bembidion trechoides Wollaston

Trechus-like Bembidion Ground Beetle (Bembidion trechoides)

The Trechus-like Bembidion Ground Beetle was described in 1877; it is, or rather was, restricted to the island of Saint Helena in the middle of the Atlantic Ocean.:

“It is only on the lofty central ridge that I have observed the B. trechoides, – where, however, in damp places generally, amongst the cabbage trees and tree ferns, it is not particularly uncommon, on the densely-covered slopes about Actaeon and Diana’s Peak; but I did not meet with it in the more western and rather less elevated parts towards High Peak and West Lodge, where the B. sublimbatum would seem to occur.” [1]

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The species was apparently not found during the latest field searches and might be extinct.

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References:

[1] T. Vernon Wollaston: Coleoptera Sanctae-Helenae. London: John Van Voorst, Paternoster Row 1877

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Photo: The Trustees of the Natural History Museum, London

(under creative commons license (4.0))
https://creativecommons.org/licenses/by/4.0/

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edited: 30.05.2021

Bembidion rufosuffusus Wollaston

Reddish-tinged Bembidion Ground Beetle (Bembidion rufosuffusus)

The Reddish-tinged Bembidion Ground Beetle was described in 1877; it is, or maybe was, restricted to the island of Saint Helena. 

“Like its immediate allies, this little Bembidium is of great rarity, and confined (so far as I have observed) to the high central ridge,  – where it occurs generally (though not always) beneath the moist stems of the rotten tree ferns about Diana’s Peak and Actaeon.” [1]

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The species appears to have not been relocated during the most recent field studies and is thus believed to be possibly extinct.

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References:

[1] T. Vernon Wollaston: Coleoptera Sanctae-Helenae. London: John Van Voorst, Paternoster Row 1877

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Photo: David Maddison 
https://creativecommons.org/licenses/by/4.0/

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edited: 30.05.2021

Bembidion megalops (Wollaston)

Large-eyed Bembidion Ground Beetle (Bembidion megalops)  

The Large-eyed Bembidion Ground Beetle was described in the year 1877, at a time when it was obviously already very rare.  

See Thomas Vernon Wollaston in the year 1877 (Coleoptera Sanctae-Helenae).:  

“It is only within the damp and rotten stems of the old tree ferns that I have observed the B. megalops; and as I merely obtained three examples, it may be presumed to be of the greatest rarity. They were all found on the lofty, densely-wooded central ridge, in the neighbourhood of Actaeon and Diana’s Peak.”  

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The most recent searches in the years of 2005 to 2006 were unsuccessful, and the species must be considered most likely extinct.  

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References:  

[1] T. V. Wollaston: Coleoptera Sanctae-Helenae. London: John Van Voorst, Paternoster Row 1877
[2] H. Mendel; P. Ashmole; M. Ashmole: Invertebrates of the Central Peaks and Peak Dale, St Helena. 2008  

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Photo: David Maddison 

(under creative commons license (4.0))
https://creativecommons.org/licenses/by/4.0/

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edited: 30.05.2021

Bembidion platyderoides Wollaston

Chestnut-brown Bembidion Ground Beetle (Bembidion platyderoides)  

The Chestnut-brown Bembidion Ground Beetle was described in 1877.  

The author of the species already mentions its rarity.:  

“The unique example of the very singular Bembidium which I have above enunciated was taken by myself from the interior of the fibrous stem of a rotten tree fern [Dicksonia arborescens L’Hér.] obtained near Diana’s Peak on the lofty central ridge; and there can be no doubt that the species which it represents is of the utmost rarity.” [1]  

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The Chestnut-brown Bembidion Ground Beetle reaches a length of about 0,45 cm.  

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The species was not found during the most recent field searches and is thus feared to be extinct. [2]  

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References:  

[1] T. V. Wollaston: Coleoptera Sanctae-Helenae. London: John Van Voorst, Paternoster Row 1877 
[2] H. Mendel; P. Ashmole; M. Ashmole: Invertebrates of the Central Peaks and Peak Dale, St Helena. 2008  

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Photo: David Maddison 

(under creative commons license (4.0))
https://creativecommons.org/licenses/by/4.0/

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edited: 30.05.2021

Bembidion nubigena Wollaston

Large St. Helena Bembidion Ground Beetle (Bembidion nubigena)  

The Large St. Helena Bembidion Ground Beetle was described in 1877, it reached a length of about 0,6 cm and was thus the largest member of its genus on the island of Saint Helena.  

The author of the species already mentions its rarity in 1877.:  

“This is the largest of the St.-Helena Bembidia, and one which there can be little doubt is extremely rare, – the only two examples which I have seen having been taken on the lofty central ridge, on the ascent of the peak known as Actaeon.” [1]  

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The specimens were found beneath rotting stems of the endemic St. Helena Tree Fern (Dicksonia arborescens L’Hér.).  

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The Large St. Helena Bembidion Ground Beetle could not be located during the most recent field searches and is thus feared to be extinct. [2]  

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References:  

[1] T. V. Wollaston: Coleoptera Sanctae-Helenae. London: John Van Voorst, Paternoster Row 1877 
[2] H. Mendel; P. Ashmole; M. Ashmole: Invertebrates of the Central Peaks and Peak Dale, St Helena. 2008  

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Photo: David Maddison 

(under creative commons license (4.0))
https://creativecommons.org/licenses/by/4.0/

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edited: 30.05.2021

Bembidion dicksoniae (Wollaston)

Tree Fern Bembidion Ground Beetle (Bembidion dicksoniae)  

The twelve species of the genus Bembidion, known to occur on Saint Helena, prey on endemic weevil species (Curculionidae), which often are dependent on rotten wood.  

In recent times, however, the climatical conditions in the remaining endemic cloud forests of Saint Helena have changed – less rain led to a much more open canopy, which again led to much drier conditions at ground level, which again seems to be quite detrimetal to the rotting process, leading to a lack of rotten wood.  

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The Tree Fern Bembidion Ground Beetle was found mostly inside, but sometimes also on the surface of the stems of the Saint Helena Tree Fern (Dicksonia arborescens L’Hér.).  

See also Thomas Vernon Wollaston in the year 1877 (Coleoptera Sanctae-Helenae).:  

“The modus vivendi of this Bembidium is precisely similar to that of the preceding and four following ones, – it having been obtained from the interior of the damp fibrous stems of the dead tree ferns on the high central ridge in the vicinity of Diana’s Peak. It is without doubt extremely rare; nevertheless I met with 17 examples of it, from first to last, by bringing amay portions of the old Dicksonias and breaking them up carefully, at home, into small fragments, over a white cloth, – which embodies a far more successful method for securing these Filicophilous Coleoptera than by examining the trunks hastily in situ.”  

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The most recent searches (2005 to 2006) failed to find any sign of the Tree Fern Bembidion Ground Beetle (and the other endemic Bembidion species), the species is therefore considered very likely extinct.  

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References:  

[1] T. V. Wollaston: Coleoptera Sanctae-Helenae. London: John Van Voorst, Paternoster Row 1877 
[2] H. Mendel; P. Ashmole; M. Ashmole: Invertebrates of the Central Peaks and Peak Dale, St Helena. 2008 

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Photo: The Trustees of the Natural History Museum, London

(under creative commons license (4.0))
https://creativecommons.org/licenses/by/4.0/

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edited: 30.05.2021

Bembidion fossor (Wollaston)

Digging Bembidion Ground Beetle (Bembidion fossor)  

The Digging Bembidion Ground Beetle seems to have been on the edge of extinction already in the 19th century.  

See Thomas Vernon Wollaston in the year 1877 (Coleoptera Sanctae-Helenae).:  

“With the exception of the B. evanescens, this is the smallest of the St.-Helena Bembidia; and it is perhaps the rarest of the whole of them, being hitherto unique. My example was taken by myself from the interior of the decayed stem of a tree fern, which I had brought away for after-examination from the vicinity of Diana’s Peak.”  

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The most recent searches in the years 2005 to 2006 failed to find any trace of this species.  

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References:  

[1] T. V. Wollaston: Coleoptera Sanctae-Helenae. London: John Van Voorst, Paternoster Row 1877 
[2] H. Mendel; P. Ashmole; M. Ashmole: Invertebrates of the Central Peaks and Peak Dale, St Helena. 2008  

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Photo: The Trustees of the Natural History Museum, London

(under creative commons license (4.0))
https://creativecommons.org/licenses/by/4.0/

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edited: 30.05.2021

Bembidion sublimbatus Wollaston

Bordered Bembidion Ground Beetle (Bembidion sublimbatus)  

The Bordered Bembidion Ground Beetle, described in 1877, was obviously restricted to a very small area at the Central High Ridge in the center of Saint Helena, where the species appears to have already been rare when it was first discovered.  

Thomas Vernon Wollaston wrote about it in 1877 (Coleoptera Sanctae-Helenae).:  

“The only spot in which I have met with this extremely rare Bembidium is towards the western extremity of the great central ridge, immediately above the house known as West Lodge, – where, early in February, I took it, on two or three occasions, at the very edge of the tremendous precipice which overlooks the Sandy-Bay crater. It was found beneath damp wood, leaves, and sticks, amongst shrubs of the Aster gummiferus [Commidendrum robustum ssp. gummiferum (Roxb.) Cronk] and common gorse; and, although it may perhaps be more plentiful on the perfectly inaccessible Aster-clothed slopes below (extending from thence to High Peak), my utmost endeavours enabled me to secure only eight or nine specimens; though as both sexes are well represented, this is more than sufficient for all practical purposes.”  

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The most recent field searches in 2008 found the type locality of the species being more or less completely eroded, yet did not produce any trace of the beetle itself, which is thus feared to be extinct.  

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References:  

[1] T. V. Wollaston: Coleoptera Sanctae-Helenae. London: John Van Voorst, Paternoster Row 1877 
[2] H. Mendel; P. Ashmole; M. Ashmole: Invertebrates of the Central Peaks and Peak Dale, St Helena. 2008

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Photo: The Trustees of the Natural History Museum, London

(under creative commons license (4.0))
https://creativecommons.org/licenses/by/4.0/

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edited: 30.05.2021