Halgerda carlsoni

Rudman, 1978

Halgerda carlsoni
Photographed by: Guido Zsilavecz

Kingdom:Animalia
Phylum:Mollusca
Class:Gastropoda
Subclass:Opisthobranchia
Order:Nudibranchia
Suborder:Doridina
Family:Discodorididae
Species:Halgerda carlsoni

Comment from Nathalie Yonow on photo #14243
I am waiting for specimens as it appears consistently different in the western Indian ocean.

Comment from Richard Willan on photo #15761
The distinction between Halgerda carlsoni and Halgerda brycei is increasingly difficult to maintain. This individual has the large gold-capped pustules weakly connected by low ridges and spotted rhinophores and gills of Halgerda carlsoni (and I have identified it as that species reluctantly), but there are no orange speckles in the depressions between the tubercles/ridges which is the situation found in Halgerda brycei.

Comment from Nathalie Yonow on photo #16012
Like brycei but with speckles on the dorsum.

Comment from Nathalie Yonow on photo #11614
Yes, the Indian Ocean version. Differs in having more black on the gills and rhinophores, and usually an orange margin.

Comment from Richard Willan on photo #13834
This photo is very important because these two individuals represent a major extension of range into the Indian Ocean for this species which was previously only known from the Pacific Ocean.

Comment from Richard Willan on photo #3341
By contrast, Halgerda malesso has a network of orange lines connecting the pustules and at least one orange line running around the margin of the mantle.

Comment from Richard Willan on photo #2572
The orange speckles on the mantle are extremely fine in this individual.

Comment from Richard Willan on photo #237
One assumes the tiny orange specks are present between the larger orange spots that cap the pustules and mantle ridges (these specks are characteristic of this species), but they are not visible in this image because of the transparency of the body.

Locality:

 

Pictures of Halgerda carlsoni

Halgerda carlsoni from General Santos, PhilippinesIdentification reviewed by Richard Willan
Posted 8 years ago
Viewed 2025 times
 
 

Similar Species

Author: Dr. Richard C. Willan

Halgerda carlsoni is most similar to Halgerda batangas. However, Halgerda carlsoni has microscopic orange speckles between the ridges (very rarely these speckles join up to form lines) and even when they are lines, they never form into a network of intersecting lines as in Halgerda batangas.

Halgerda malesso has much lower pustules, yellow spots and yellow lines. There are far fewer yellow lines than in Halgerda batangas.

Halgerda bacalusia has the summits of the ridges with strong dark orange lines and microscopic orange speckles between the ridges.

Here a description from Dr. Dave Behrens:
Halgerda bacalusia: broad orange lines follow the ridges to the orange tipped tubercles
Halgerda batangas: network of orange lines between the tubercles, rather than a series of spots
Halgerda carlsoni: the are lines of minute orange spots between the tubercles
Halgerda malesso: no lines between the tubercles, only along the margin
Halgerda stricklandi: orange tubercles arranged randomly, not in ridges. Orange spots not connected

Halgerda bacalusia from West Java, IndonesiaIdentification reviewed by Richard Willan
(22 photos)
Halgerda malesso from Saipan, Nthn. Mariana Islands
(13 photos)
 
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