Hi! I found a similar species, but in the shores of the Caribbean sea, and were identified as Loxoconcha. But I work more with non-marine ostracodes, so maybe someone else can help you more. Good luck!

Hi Christabel,

It's a very interesting and quite diverse fauna. And I do not know any publication dealing with brackish water ostracods from Vietnam. It would be worth to publish your fauna.

I'm not familiar with SE Asian ostracods but know some brackish faunas from Europe, Africa and the Americas. So, I can guess for many genera but not the species.

Fig 1-5 = Palmoconcha or a related taxon. You need an internal view of an adult specimen to check.

Fig 6 = Maybe a leptocytherid taxon. Needs an internal SEM picture for identification.

Fig 7 = probably Loxoconcha

Fig 8 = probably another Loxoconcha

Fig 9 = and another Loxoconcha

Fig 10 = maybe another Loxoconcha

Fig 11 = I do not know - internal view needed

Fig 12 = maybe a juvenile Cyprideis

Fig 17 = Leptocythere?

Fig 18 = Pontocythere?

Fig 19 = maybe Aurila or related taxon

Fig 20 = I do not know, but it looks juvenile

Fig 21 = I do not know

Fig 22 = Callistocythere

Fig 23 = Leptocythere

Fig 24 = Callistocythere?

Normally you can identify a species relying on the external view alone (you made nice pictures), but only if you know this species already. Otherwise you need to have internal views as well for getting information about characteristics as hinge structure, muscle scars, duplicature etc. Sometimes a transmitted light photo would be supporting because of marginal pore channels visible. If you would internal views I could try to check some of the genera and maybe more. I'm interested in brackish water faunas around the world.

All the best,

Peter

Liseth Pérez Thank you for the well wishes.

Peter Frenzel Thank you for suggesting the possible genus. There has been 2 papers published by Tanaka et al (2009, 2011) on Vietnam brackish ostracods.

Here are the references if you are interested:

Tanaka, G., Komatsu, T. and Duc Phong, N. (2009). Recent ostracod assemblages from the northeastern coast of Vietnam and the biogeographical significance of the euryhaline species. Micropaleontology, 55(4), pp.365-382.

Tanaka, G., Komatsu, T., Saito, Y., Nguyen, D. and Vu, Q. (2011). Temporal changes in ostracod assemblages during the past 10,000 years associated with the evolution of the Red River delta system, northeastern Vietnam. Marine Micropaleontology, 81(3-4), pp.77-87.

I have forgotten to include my guesses of the genus/species earlier:

1-10: loxoconcha sp. 

1 & 2: loxoconcha vietnamensis (Tanaka et al, 2011) 

7: loxoconcha malayensis (Faiz, Mohammed and Omar, 2017)

8: loxoconcha paiki (Dewi, 1997)

11: cyprideis sp. or pontocypria (Dewi, 1997) 

16: mutilus sp. (Whatley and Zhao 1987; Mostafawi 1992)

18: phlyctenophora orientalis / parakrithella sp. (Mostafawi, 1992)

20: keijella sp.

22: callistocythere sp.

23-24: tanella sp.

I would look into those genus that you have suggested and try to get some images of the innerside of the valves. Thank you for the reply and the help .

I got this contact from Ivana K. regarding experts in that region.

Le Doan Dung works on Loxoconchidae in Vietnam. This is his email [email protected]

good luck!

Lis

Fig. 11 (adult left valve) and fig. 12 (juv. left valve) can be identified as Neocyprideis agilis (Guan, 1978). This is an interesting new record of this species. It is known from the Pliocene of Yingli, Haikang County China, the Delta of the river Mahakam, Kalimantan, Indonesia, the river Mae Khlong, Thailand, Pentai Kenjeran, Surabya, Java, and now from Vietnam. I'll send you a pdf file of my paper on ton this subject to your email address.

Liseth Pérez thank you very much for your help and even going to the extent to recommend me a contact. I'm really grateful for the help you have given.

Many thanks,

Christabel

Karel Wouters thank you very much for taking the time to help in identifying the species and for sending me the paper. I am really grateful for the help.

Yours sincerely,

Christabel