The subspecies or is a variety of the nominal species, although it is influenced by geographic and environmental factors or being a specialization process in progress is destined to become itself a species. DNA is a further proof of its specialization. (evolution)

La sottospecie o è una varietà della specie nominale sebbene sia influenzata da fattori geografici ed ambientali oppure essendo un processo di speciazione in atto è destinata a diventare essa stessa una specie. il DNA è una ulteriore prova della sua speciazione. (evoluzione)

Morphology, if it is a constant characteristic of a group, can always be tested but in the field of inflexion variability.

La morfologia se è caratteristica costante di un gruppo può essere probante ma  sempre nell'ambito della variabilità infraspecifica.

I wonder how will we define subspecies when we exclude morphology esepcially in groups having very low variation in DNA sequences? To me the subspecies concept is backed strongly by morphology than any other subject.

I'm agreed with you. I don't use the term "subspecies", because (for me) it's one term ambiguous; I prefer to use "geomorphs". I consider one "species" with a large geographical distribution a complex of different geographical populations interfecunds, inside of these (if these have a large ecological apportionment) we can found different "ecomorphs" and a lot of individuals variations, sexual dimorphisms, etc.: Just simples "variety".

Nice conversation! 

what about subspecies being more for higher animals (for conservation, protection etc.) ?? 

your view please

Adding another question to this

Can someone provide good insights into the molecular level changes and chemotaxonomy on subspecies level?

Kindly see the attached publication.

Morphology wrt me in taxonomy  is the best way to distinguish between species and even subspecies.

Dear All - I'm very happy about the progress of discussion. All points of view around this important concept are welcome; I need of all yours contributions for to improve my opinion.

It is difficult to satisfy an objective analysis of the term subspecies. The species with great ecological amplitude can present diverse phenotypic expressions and they continue being the same species. Some ecotypes have been confused with "subspecies". Perhaps on a temporal scale these ecotypes can evolve into species.

Thank you Narciso - My point of view it's the same, but remain the question: What is the correct significance of the concept of subspecies? And it's correct to continue at use this term?

Morphology in taxonomy is very important, but what is the border between species, subspecies or variety?

Hi Sergio - For me "varieties" are all individual morphological variations (sexual, gerontological forms, ecc.) and it's possible to found them in all subspecies (typical too), but also in all ecomorphs inside of many subspecies. But the principal question still remains: What is the real significance of "subspecies"?; it's correct to continue at use this again, or it's more correct to consider various geomophus inside the species? For me "varieties" are all individual morphological variations (sexual, gerontological forms, ecc.) and it's possible to found them in all subspecies (typical too), but also in all ecomorphs inside of many subspecies. But the principal question still remains: What is the real significance of "subspecies"?; it's correct to continue at use this again, or it's more correct to consider various geomophus inside the species? 

Hi Gianluigi, so without subspecies there will be only species!

Hi Sergio - No, for sure it's a misunderstanding. For me the species could be uniform in all the his distribution (no subspecies), or a complex of various populations (inter-fecundes), morphologically differents (subspecies? or geomorphus?) and, possibly, maybe future good species.

There are not enough arguments to support the concept of subspecies. I believe that many times the effect of phenotypic plasticity with a possible subspecies has been confused.

Exactly Narciso! "There are not enough arguments to support the concept of subspecies" and, consequently, we need to review all the necessary "subspecific" nomenclature.

Especially in estuarine / brackish water environment ..there  are lot variation, due to difference in salinity pattern and other environmental forcing...

Truly Jayachandran- In the past, but still today, some authors insist on establishing new "subspecies" for any simple morphological variation linked to ecological factors. It is necessary to establish once and for all that a species with a large geographical distribution can differentiate in individual populations (geomorphs) and that within the same (if the species resides in different environments), there may be some ecomorphs. The vague concept of "subspecies" should be completely abandoned, while it would be desirable to establish a specific nomenclature for these units.

sir, subspecies and varieties so confusing, eg. Villorita cyprinoides cochnensis, cochinensis is variety or subspecies?so ecology is relevent in this case?

Dear Henk - First of all thank you for masterfully enlightening on the concepts of "Dobzhanskyanian & Mayerianian" memory about the allopathy/sympathy, as well as on the differences between planctotrophic and  lecitotrophic larvae and related distributive implications. I want to reassure you that I have no intention of proposing any "new term" such as (Geomorphic or Ecomorphic), as existing and accepted (ICZNs) are already sufficient and exhaustive, but only reflect on their meaning. The discussion I have tried to stimulate just wants to compare the different opinions that each of us can have, but also the questions that arise in those who observe the evolutionary process of some species; It is not my intention to try to scourge any granitic conviction.

 Dear Jayachandran - Yours is a million dollar question. I do not know the Cyrenidae and I have no precise idea about it, but if the geographical distribution of "cochinensis" is completely isolated from the typical "cyprinoides", it may be a subspecies, probably linked also by ecological factors that may have produced constant morphological differences Throughout the population.