deiss­neri

deissnerix

Kot­te­lat & Ng 1998

First descrip­tion: Valid today:Parosphromenus bin­tan, a new osphrone­mid fish from Bin­tan and Bangka islands, Indone­sia, with redescrip­tion of P. deiss­neri. Ichthy­olog­i­cal Explo­ration of Fresh­wa­ters, 8: 263272. – Until the pub­li­ca­tion of this new descrip­tion, the first descrip­tion was valid: P. Bleeker, Negende bij­drage tot de ken­nis der vis­chfau­na­van Banka. Natu­urkundig Tijd­schrift voor Ned­er­land­sch Indie, 18:359378.

The redescrip­tion with the approval of the nomen­cla­ture author­ity, ICZN, a cen­tury after its first descrip­tion, is very unusual, but nev­er­the­less fol­lows the reg­u­la­tions. The ICZN con­firmed this in the fol­low­ing pub­li­ca­tion: ICZN, 2000.Opinion 1946th Osphrone­mus deiss­neri Bleeker, 1859 (cur­rently Parosphromenus deiss­neri; Oste­ichtyes, Per­ci­formes): holo­type replaced by a neo­type. Bul­letin of Zoo­log­i­cal Nomen­cla­ture, 57 (1): 60

Back­ground: in the nine­teen nineties it was already clear that the orig­i­nal view, there was only one Parosphromenus species, had been wrong. It was also obvi­ous that the licorice gouramis, found up to that date and usu­ally labelled as “P. deiss­neri”, must have belonged to dif­fer­ent species. There­fore there was an inter­est to exam­ine Bleeker’s orig­i­nal fish (one spec­i­men) again in the light of this new find­ings. When Kot­te­lat and Ng did so, quickly three things became clear. First, the spec­i­men was in very poor con­di­tion. Sec­ond it was a female and thus lacked impor­tant species dif­fer­en­ti­a­tion char­ac­ter­is­tics; such as colours, which barely remain in the con­served state. Third, by this time it was already known that at least two dif­fer­ent Parosphromenus species exist on Bangka, which can be dis­tin­guished struc­turally by the shape of their tail fin. The cau­dal fin would have been an impor­tant struc­tural dif­fer­en­ti­a­tion char­ac­ter­is­tic, but the spec­i­men lacked this. Mean­while, because the old holo­type could no longer be used to decide which of the two Bangka species really is deiss­neri, the two ichthy­ol­o­gists requested to assign a neo­type and to describe the species on this basis. This pro­posal was accepted. In this case it was decided that not the species with the round tail fin, but the other with a clear fil­a­ment in its tail fin would be (deiss­neri). (Remark PF: If the deci­sion had been taken to select the other species, much of the con­fu­sion about the species´ name could have been avoided. But it is now idle to spec­u­late about it). The other, round finned species was then described as P. bin­tan, because it occurs on the island Bin­tan as well.

Char­ac­ter­is­tics: Over­all length max. 5 cm, mak­ing it one of the largest licorice gouramis. Dor­sal struc­ture: XII-​XIII, 6, total 1819, Anal: XII-​XIII, 810, total 2123. ♂ in nup­tial plumage struc­turally well iden­ti­fi­able by the tri­an­gu­lar, up to one cen­time­ter long black cau­dal fil­a­ment. Addi­tion­ally it is very char­ac­ter­is­tic that the light pat­terns in the unpaired fins are not con­tin­u­ous, but sin­gle short light bands. Espe­cially in the cau­dal fin this char­ac­ter­is­tic is very obvi­ous, as the lines located there have a hor­i­zon­tal and nearly par­al­lel off­set. P. deiss­neri males are there­fore among the most eas­ily rec­og­niz­able licorice gouramis (see illustration).

Sim­i­lar species: the risk of con­fu­sion with other licorice gouramis is low for the males, due to the phe­no­typic dif­fer­en­ti­a­tion, which is based on struc­tural (cau­dal fin with dis­tinct black fil­a­ment) dif­fer­ences and on the char­ac­ter­is­tic colour pat­terns. For the females the risk is higher; here the (less obvi­ous) dif­fer­ences in physique have to be con­sid­ered. How­ever it has to be pointed out again that the per­ma­nence of using the his­toric name until 1998 for var­i­ous kinds of licorice gouramis, still con­fuses large parts of the aquar­ium hobby, although, at least for the males, a dif­fer­en­ti­a­tion is almost no prob­lem. Not only in the trade, but also in many inter­net pub­li­ca­tions and in un-​specialised gen­eral aquar­ium arti­cles and books,this wrong des­ig­na­tion still occurs almost unabated.

Occurence/​Distribution: fol­low­ing the first descrip­tion, deiss­neri is endemic on the Malayan island Bangka, but has been found later on the neigh­bour island Beli­tung as well. Obvi­ously it has not spread further .

Threat: Due to the restric­tion of occur­rence on these two islands the threat is very high.

Discovery/​First import:

Trade: as already men­tioned, it is still almost impos­si­ble to dis­en­tan­gle the name and iden­ti­fi­ca­tion con­fu­sion in the inter­na­tional trade. Only grad­u­ally have the exporters and importers realised that there was this new descrip­tion, which for­bids the iden­ti­fi­ca­tion of most of the licorice gouramis, offered in trade, as deiss­neri. Unaf­fected by this, many of the licorice gouramis are still incor­rectly traded as deiss­neri. How­ever, until a few years ago, real P.deissneri have obvi­ously never been traded. Only recently have there been few imports to Europe or Amer­ica, but due to the name con­fu­sion these fish have soon dis­ap­peared and were lost in the total­ity of traded licorice gouramis, before spe­cial­ists could get hold of them. The aquar­ium strains, swim­ming today in a few tanks, go back to pri­vate imports (e.g. Kopic, Brown, ).

Care /​Breed­ing: No spe­cial con­di­tions that devi­ate from the usual Paros water stan­dards are required. How­ever, note that deiss­neri is one of the largest and strongest licorice gouramis. There­fore, they should not be kept in the small­est tank. In the long run, a 12-​liter tank would be too small and a 25-​liter tank would be the min­i­mum. The nests can be large (over 100 eggs, but usu­ally less).

Behaviour/​Particularities: no par­tic­u­lar­i­ties. Hor­i­zon­tal to head down courtship. Often with very dis­tinct foam nest, some­times only rudi­men­tary nest. Large deiss­neri belong to the most impres­sive forms we know.

Lit­er­atur:

Weblinks:

Parosphromenus deissneri male Copyright Horst LinkeParosphromenus deissneri male Copyright van HoekParosphromenus deissneri male Copyright KeibelParosphromenus deissneri male Copyright KeibelParosphromenus deissneri male Copyright KishiParosphromenus deissneri habitat Copyright KishiParosphromenus deissneri habitat Copyright KishiParosphromenus deissneri habitat Copyright KishiParosphromenus deissneri habitat Pulau Bangka Copyright Kishi

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