Danio year 2009: Danio tinwini

The year is isn't over, and the snow did not fall over Stockholm yet, so it may be a bit early to summarise the year. But it might be better to start early, not to end up in december 2010 summarizing 2009, and then it has to be piece by piece. Writing this, I am reminded of one of the most famous aquarium books, Aquarienfische in Wort und Bild, which was issued over a period of 30 years in instalments of a smaller number of sheets, and the authors were indeed writing continuously on it between 1932 and 1962. In the 1950s there were similar initiatives elsewhere in Europe, e.g., the Belgian Vissentlas, but I have not kept track of them. Also TFH publications tried, much later, to publish a loose-leaf edition of Exotic Tropical Fishes, and the German cichlid society sent out species descriptions with their journal supposed to be collected by the subscribers. Of course, this is in most cases an awkward way of publishing where the customer is the big loser. The following scenarios are possible:

• Publication terminates after a smaller number of pages. You end up with a quarter or half of a book.
• Publication goes on indefinitely, with or without revisions of outdated pages. You end up with a book containing almost duplicate pages, and a span of many years between the earliest and the latest information (could be blurred b/w photos mixed with excellent digital colour photos. Half the book will be outdated.
  
• You stop subscription and end up with a half book
• Everything completes but in the meantime you already had to buy some complete books, just not to stay ignorant about everything from H to Z.

Die Aquarienfische in Wort und Bild (there is also the corresponding Aquarienpflanzen) is an exception among the bad examples because it (1) terminated a long time ago, so all you can buy now is the complete book (€70-150 on eBay), and (2) it was actually quite complete in coverage, and especially the species descriptions were more detailed than anything in other contemporary aquarium books. I am actually not quite sure when it was published, but it seems it started in 1932, and went on till 1962, with Hermann Meinken (1896-1976) as the sole author after co-authors Maximilian Holly (*-*) and Arthur Rachow (1884-1960) long before had retired from writing. Die Aquarienfische in Wort und Bild was a highly influential work, the mother of all other European aquarium books.

That it wasn't published after 1962 seems likely because the description of Brachydanio frankei, described by Meinken in 1963, is missing. Every other fish imported to Germany up till the late 1950s/early 1960s are there, and Meinken had a particular interest in danios.

Now we are getting to the point: Brachydanio frankei was, at that time, known only from aquarium specimens. It is still not known from the wild, as already pointed out in an earlier post about fish from nowhere. Meinken lists the following species of danios:

Danio devario
Danio malabaricus
Brachydanio kerri
Brachydanio albolineatus
Brachydanio nigrofasciatus
Brachydanio  rerio

That is a very short list. (And by the way, Brachydanio is presently considered a junior synonym of Danio, and Meinken's Danio are now in Devario; but they are all danios.) A much larger number of species of Rasbora are described in the same book. At present it looks to me that there are more danios than rasboras in the shops, but I may may be biased.

  

Danio rerio, aquarel by Curt Bessiger, used in Die Aquarienfische in Wort und Bild.

The most characteristic about Danio frankei is the colour pattern, which is golden with small brown or black spots. At the time that was quite remarkable because all known danios (listed above) were striped (except that the stripe in Devario devario is not so prominent, and Danio nigrofasciatus has spots on the abdomen. Over the time, no wild specimens of D. frankei appeared, and it has turned out rather certain that it is a colour mutation of the zebrafish, Danio rerio.

In the original description of Danio frankei, Meinken wrote (my translation from the German):

Shortly before the end of the year 1962, through my old friend Heinrich Grauel from "Vivarium-Bremerhaven", my friend Diplom-Biologe Hanns-Joachim Franke in Gera/Thüringen, gave me  six captive bred specimens of a very handsome Brachydanio novelty with the request that I study the specimens, if possible identify them and give them a name. According to the information from Mr Grauel, at that time Mr Franke already had bred several hundred specimens of this species in his breeding tanks. Unfortunately the novelty was lacking a name.

Upon my immediate checkback concerning details about the importation and my notice that -- in case the animals would represent a scientifically still unknown and undescribed novelty -- a determination based on captive bred specimens would be unreliable because that could lead to mistakes, Mr Franke then most friendly told me that he had obtained the import specimens from the familiar and active Diplom-Biologe Stanislav Frank in Prague. Unfortunately, the place of capture was unknown also to Mr Frank. That the animals came from India was only a very weak consolation, because first all Danio and Brachydanio species come from India and the Indo-Malayan area, and second India is large, about several times larger than the previously undivided Germany. Mr. Franke, however, made the great sacrifice in the interest of science and nomenclature, killing four of his import specimens and sent them to me for examination.

Meinken then went on with a very detailed description, a lamentation of the lack of locality data, and finally, a long discussion about relationships. According to Meinken, D. frankei would be most closely related to B. tweediei (from Malaysia), a nominal species currently synonymized with D. albolineatus.

Leopard danio. Preserved aquarium specimen from Taiwan.

That did not stop other leopard danios from coming in. The first was Danio kyathit, described by Fang in 1998. The second was just described by me and Fang based on a large series collected by U Tin Win in the same region as D. kyathit, and we named it Danio tinwini. 

Danio tinwini, female paratype.

Danio tinwini is spotted and the spot pattern is quite similar to that of D. kyathit, but not so much to that of the leopard danio. It is a much smaller species than either D. kyathit or the leopard danio, however, and external morphological characters suggest that it is more related to D. nigrofasciatus or D. aesculapii. It is indeed a remarkably small species. The largest wild male examined was 21.7 mm in standard length, the largest female 25.6 mm. That is almost as small as the smallest Danio species (D. margaritatus, 21.3 mm).  What provokes most thought, however, is the fact that the only two spotted danios, D. kyathit and D. tinwini occur in the same general area (but not syntopic), and are not closely related. Would we be surprised if D. frankei were found in northern Myanmar one day as well?

Danio tinwini lives together with a much more famous fish, Danionella dracula, the Vampire or Dracula fish. Much more we do not know about the natural habitat och accompanying species. You can read all the technical details about Danio tinwini in the Open Access original description.

References
Holly, M., H. Meinken & A. Rachow. 1932-1962. Die Aquarienfische in Wort und Bild. Kernen, Stuttgart, Loose-leaf publication, 1328 pp.

Kullander, S.O. & F. Fang. 2009. Danio tinwini, a new species of spotted danio from northern Myanmar (Teleostei: Cyprinidae). Ichthyological Exploration of Freshwaters, 20: 223-228. [errata:  p. 227, col 2, para 2, line 10: "1" should be "4"; p. 228, col. 1, line 3: "19.3" should be "21.2"]

Meinken, H. 1963. Mitteilungen der Fischbestimmungsstelle des VDA XLII: Brachydanio frankei spec. nov., der Leopard-Danio. Monatsschrift für Ornithologie und Vivarienkunde. Ausgabe B. Aquarien und Terrarien, 10:75-79.

Perplexion
*-* I cannot find any information about Maximilian Holly. I don't even know where to start...?

Photo credits:
Top image: living Danio tinwini,Sven O Kullander, CC-BY-NC
Leopard danio and Danio tinwini, Sven O Kullander, CC-BY-NC
Danio rerio aquarel, public domain.

Penis fish

My friend Ralf Britz (Dracula fish), just released the description of a species related to the Dracula fish (Danionella dracula), viz., the Penis fish (Danionella priapus), which is number four in the genus (D. mirifica, and D. translucida were described earlier). This was a bit of of concern to me. Is the evolution of Danionella Nature's idea of a freak show (or a Japanese game show...)? Or perhaps the fishy Fantastic Four (Bloodsucker, Flasher, Beauty, and Invisible). By the way, there is a Marvel character called Priapus.

Danionella priapus, the male holotype. Photo (c) Ralf Britz, reproduced with kind permission.

The penis, a worm-shaped intromittent reproductive organ characterizing mammals, some reptiles and very few birds, has fascinated male ichthyologists for a long time. The typical penis, in placental mammals, contains some spongy tissue and ducts for urine and sperm. Many species of fish with various elongate reproductive structures have been named with reference to the penis, or after the Greek minor deity commonly associated with an oversize penis (list below). The only group of fish that had escaped until 2008 were the Chondrichthyans, equipped with the most penis-like intromittent organ among fishes, known as mixipterygia and a synapomorphy of the group. Perhaps because in Chondrichthyans, the male reproductive organ, a modifiction of the pelvic fin, is paired. Yes, they have two. Theoretically a male shark could mate with two females simultaneously, but there seems to be no observation of such act and perhaps for reason that such pairing must be very complicated to coordinate, no other vertebrates invested in double external reproductive organ. But we all do maintain a paired internal set, except that in many fishes there is only one ovary. Marsupials, it must be added, are an exception here as in so many other respects. Males usually have a bifurcate penis unfit for peeing with and consequently used only for copulation. Females have two vaginas (with common opening), each with its own uterus, and a third for parutition.


In actinopterygian fish, sperm-transmitting elongate structures, intromittent organs, are technically known as gonopodium (live bearing poeciliids), or andropodium (Hemiramphidae; Goodeidae) in livebearers and are formed by modifications of anal-fin rays. Egglaying fish are commonly equipped with a genital papilla through which sperm or eggs are released. The genital papilla of females is sometimes referred to as the egg-laying tube or ovipositor. It is very impressive in bitterlings in which it is used for depositing eggs deep inside bivalves. None of these terms were considered suitable for a fish name, however.

What about naming fish after mammal female external reproductive organs? There is the south Asian Trypauchen vagina Schneider, 1801, a goby, for which Schneider did not explicitly explain the etymology but gave the local name, obviously based on information from the collector/correspondent in Danish India (Tranquebar), Christoph Samuel John (1747-1813), "Sewwöli, i.e., vagina cultri rubra, Tamulice", what would mean: "Sewwöli, that is, red knife slide, of the Tamils", i.e., nothing to do with humans. It is a slender, caudally tapering fish with a predominantly red colour. Schneider gave the same name also, spelled Sewwöti, for Cepola coecula (junior synonym of another goby, Taenioides anguillaris), another slim, red fish. There are also Thai cyprinids Probarbus labeamajor and P. labeaminor, named by Tyson Roberts in 1992, but for the thick and thin lips, respectively, of the mouth.

Trypauchen vagina

Priapos was an ancient Greek god of fertility, usually depicted with an oversize, erect penis, and according to Lemprière a rather deformed figure, not worthy of residing in the Olympics, and on the whole more of a rapist and rascal than anything else, requiring sacrifice in the form of of asses (Equus africanus, that is). This sad figure seems eventually to have converted into a garden gnome in Western garden culture. In Rome, Mutunus was the approximate equivalent. There is no fish named for Mutunus.

Interestingly, a very large number of fish possess a well developed genital papilla. In cichlids, for instance, it is long and pointed in males, but short and swollen, with at least a transverse fold in females, although there is variation, and in some genera it is hard to tell males and females apart on the papilla alone. Cottids are also well known for the long male genital papilla, as exemplified by Phallocottus, and it is also prominent in gobioids, but I could not find any relevant name in that group. The group that have most of the penile names are the livebearing poeciliids, in which the anal fin is modified to an elongate intromittent organ.

Back to Fantastic Four. As Ralf points out, these miniature fishes, and other miniatures as well, are remarkable not only for their small size. They also have conspicuous novel characters which gain significance particularly in a small body. The elongate fangs of Danionella dracula are the only oral tooth structures known from cypriniforms, and may very well be the beginning of a radically different evolutionary lineage. Males of Paedocypris (another miniature), and D. priapus have developed accessory sexual organs not known from other cyprinids, and may be actively evolving in organs that larger, more long-lived fish with longer generation times cannot afford to invest in.

Small size apparently calls for radical solutions, and those radical solutions may be the matter of evolutionary leaps. We are accustomed to think, at least I am, of evolution among fishes being based on something mid-sized rather normal fusiform, which then strikes off in different feeding niches, becoming smaller or larger depending on energy householding. But, that does not seem to lead to much real diversity (after all, all cichlids and cyprinids look very much the same). Radical morphological change as within Danionella may be one of the clues to evolutionary stepping. Most striking about species of Danionella is that they are so radically different from each other. Had they been a few centimeters longer, they would probably have been placed in different genera, but now they are considered as specialized close relatives. So, there is something important to be learned from the penis fish and friends.

Not all small fish present novel characters or behaviour, but the phenomenon seems to be particularly evident in progenetic species. This is then seen clearly in the larvae of many marine fishes in particular. The amazing spinature of many pelagic acanthopterygians, and the strange leptocephali of eels, demonstrate this. In this case, the "normal" adult provides for a backup morphology, should juvenile experimentation fail, but if these fishes turn progenetic and skip the adult stage, they may blast off in a different morphological evolutionary trajectory.

Origin of a new phylum? Larva of an unidentified species of the family Gempylidae. Photo NOAA.

Can I then go so far as to postulate that larval specializations must precede progenesis? Or does necessarily specializations have to come along with or after progenesis? Or am I making it unnecessarily difficult?

As you can now see, this post is all about evolution. But, you are right: I am also fascinated by biological nomenclature as a graffitti wall...

Anyway, here is the list of the penis fishes, based on active search in Catalog of Fishes. Many of them do not have a common name, so here is a goldmine for those constructing common names based on translations of the scientific ones ... Of course all names are masculine, and all the authors are male... And, by the way, penis means tail, but is never used in that meaning, and the word phallos wasn't intended for other than the drawings and sculptures, and again is not used in that meaning.

Phalloceros Eigenmann, 1907. Poeciliidae: Poeciliinae.

Allophallus Hubbs, 1936. Synonym of Carlhubbsia Whitley, 1951. Poeciliidae: Poeciliinae.

Arthrophallus Hubbs, 1926. Synonym of Gambusia Poey, 1854. Hubbs, 1926. Poeciliidae: Poeciliinae.

Aulophallus Hubbs, 1926. Synonym of Poeciliopsis Regan, 1913. Poeciliidae: Poeciliinae.

Curtipenis Rivas & Myers, 1950. Synonym of Poecilia Schneider, 1801. Poeciliidae: Poeciliinae.

Dicerophallus Alvárez, 1952. Synonym of Gambusia Poey, 1854. Poeciliidae: Poeciliinae.

Flexipenis Hubbs in Rivas, 1963. Synonym of Gambusia Poey, 1854. Poeciliidae: Poeciliinae.

Furcipenis Hubbs, 1931. Synonym of Alfaro Meek, 1912. Poeciliidae: Poeciliinae.

Heterophallina Hubbs, 1926. Synonym of Gambusia Poey, 1854. Poeciliidae: Poeciliinae.

Heterophallus Regan 1914. Synonym of Gambusia Poey, 1854. Poeciliidae: Poeciliinae.

Orthophallus Rivas 1963. Synonym of Gambusia Poey, 1854. Poeciliidae: Poeciliinae.

Phalloptychus Eigenmann, 1907. Poeciliidae: Poeciliinae.

Phallotorynus Henn, 1916. Poeciliidae: Poeciliinae.

Plectrophallus Fowler, 1932. Synonym of Brachyrhaphis Regan, 1913. Poeciliidae: Poeciliinae.

Priapella Regan, 1913. Poeciliidae: Poeciliinae.

Priapichthys Regan, 1913. Poeciliidae: Poeciliinae.

Trigonophallus Hubbs, 1926. Synonym of Brachyrhaphis Regan, 1913. Poeciliidae: Poeciliinae.

Ctenophallus Herre, 1939. Synonym of Neostethus Regan, 1916. Phallostethidae.

Gulaphallus Herre, 1925. Phallostethidae.

Mirophallus Herre, 1926. Synonym of Gulaphallus Herre, 1925. Phallostethidae.

Penicelinus Bolin, 1936. Synonym of Icelinus Jordan, 1885. Cottidae.

Phallichthys Hubbs, 1924. Poeciliidae: Poeciliinae.

Phallobrycon Menezes, Ferreira & Netto-Ferreira, 2009. Characidae.

Phalloceros Eigenmann, 1907. Poeciliidae: Poeciliinae.

Phallocottus Schultz, 1938. Cottidae.

Phalloptychus Eigenmann, 1907. Poeciliidae: Poeciliinae.

Phallostethus Regan, 1913. Phallostethidae.

Solenophallus Herre (ex Aurich), 1953. Synonym of Neostethus Regan, 1916. Phallostethidae.

Galeus priapus Séret & Last, 2008. Scyliorhinidae.

Online reference:
Britz, R. 2009. Danionella priapus, a new species of miniature cyprinid fish from West Bengal, India (Teleostei: Cypriniformes: Cyprinidae). Zootaxa 2277: 53-60. (Abstract only; not Open Access)

Book references:
Lemprière, J. 1984. Lempriere's classical dictionary. Bracken books, London, xv+734 pp. Original: A classical dictionary; containing a full account of all the proper names mentioned in Ancient authors. Reading, 1788. [Second edition, 1792] [11th edition, 1820]

Image credits:
Cover of Fantastic Four from Wikipedia, copyright, but used in fair sense, to illustrate that Nature and Fiction sometimes go hand in hand, you just need the imagination.
Trypauchen vagina from Wikimedia Commons
Gempylid larva from Wikimedia Commons.
Danionella priapus courtesy Ralf Britz