Bentheogennema burkenroadi Krygier and Wasmer, 1975

Common name(s): Burkenroad blunt-tail shrimp
Synonyms:
Phylum Arthropoda
 Subphylum Crustacea
  Class Malacostraca
   Subclass Eumalacostraca
    Superorder Eucarida
     Order Decapoda
      [Informal Group] Natantia
      Suborder Dendrobranchiata
       Family Penaeidae
Bentheogennema burkenroadi, bathypelagic 100 mi off Point Conception, CA
(Photo by: Dave Cowles, Sept 1995)
Description:  As a Penaeid (Dendrobranchiate) and thus not a true (Caridean) shrimp, the epimera of the second abdominal segment of this animal do not overlap the epimera of segments 1 and 2 (photo).  Unlike Caridean shrimp and crabs, Dendrobranchiate crustaceans have gills which are tree-like in structure (photo).  As a member of family Penaeidae, this shrimp is distinguished from family Sergestidae by having chelae on all 3 of its first 3 pairs of pereopods (photo) (Sergestidae is chelate only on pereopods 2 & 3).  Also, members of family Penaeidae almost always have a well-developed rostrum while the rostrum of sergestids is usually very small.  The most obvious distinguishing features of Bentheogennema shrimp to me on first glance is that they have long setae fringing their first antennae and antennal scales, making them appear to have a long moustache (photo); plus they have large pereopods and maxillipeds which are colored very dark red, which they hold bunched together under their body in a dark mass.  Bentheogennema burkenroadi has curved, vertical transverse grooves on the dorsal carapace which cross the median ridge but are not interrupted by it (photo).  The distinctive rostrum has a line of forward-pointed setae from the dorsal spine to the front (photo).  The telson has only 1 pair of stout median spines on its truncate tip (photo).

How to Distinguish from Similar Species: Bentheogennema borealis has a median ridge dorsally on its carapace which interrupts the transverse carinae, + the telson has 2 pairs of stout median spines.

Geographical Range:  Northeastern Pacific ocean

Depth Range:  Bathypelagic

Habitat:  Bathypelagic

Biology/Natural History:


 
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References:

Dichotomous Keys:
  Kozloff 1987, 1996
  Wicksten, 2009
 

General References:
  Butler, 1980

Scientific Articles:
  Krygier, Earl E. and Robert A. Wasmer, 1975.  Description and biology of a new species of pelagic penaeid shrimp, Bentheogennema burkenroadi, from the northeastern Pacific.  Fishery Bulletin 73:4 pp. 737-746

Web sites:
 


General Notes and Observations:  Locations, abundances, unusual behaviors:


The epimeron of abdominal segment 2 does not overlap that of segments 1 and 3.  This view shows the thorax to the left and abdominal segments 1-4 with the bases of the pleopods.
Photo is of a preserved specimen.



This animal swims through the water with its feathery pleopods.  The head of this preserved specimen is to the right.



In this photo the dendrobranchiate (tree-like in structure) gills can be seen hanging from below the carapace.  In this species the gills are podobranchs, which is an epipod gill attached to the coxa (basal segment) of the legs.
These podobranch gills are arising, left to right, from the third maxilliped and from pereopods 1-3.
Photo of a preserved specimen



As a member of family Penaeidae, pereopods 1-3 are all chelate.  This photo of a preserved specimen shows the chelae on pereopods 1 (left) to 3 (right).

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Both the antennules (first antennae) and the antennal scale have prominent setae which together make the animal look like it has a thick moustache from a distance.
Note also the long second antennae, visible on the left side of the animal (top), which extends forward, has a sharp bend, and has a long flagellum extending back.
Photo of preserved specimen.



The long antennal flagellum is lined along one side with a double row of curved setae which arch outwards and then curve toward one another like the ribs of a vacuum cleaner hose.
Shorter, enervated setae are found in the middle of the circle formed by the long setae.  Together, this structure forms a lateral-line like detector of near-field sound or vibrations.



As can be seen in this dorsal view of a preserved specimen, the curving vertical grooves on the carapace cross the mid-dorsal ridge but are not interrupted by it.



The same grooves plus other carinae can be seen here in this side view of the carapace
 



The distinctive rostrum has a dorsal spine, a line of forward-pointing setae, and an anterior spine.



The telson is shorter than the uropods.  It ends with only one pair of stout median spines, (with a row of setae between them)


Authors and Editors of Page:
Dave Cowles (2006):  Created original page