Sud Africa – Durban, 20-25 Maggio 2001
Questa volta l’Indo-Pacific Fish Conference che si svolge ogni quattro anni, dal 1981, è stata organizzata dall’Istituto di ricerca oceanografica il cui organizzatore è stato: Ansie Dippenaar-Schoeman e la leggendaria Marjorie Courtenay-Latimer (foto a sinistra), è stata l’ospite d’onore il giorno dell’apertura, ricordi dell’importanza che ha avuto nella scoperta del 1938…
Sud Africa – Durban, 20-25 Maggio 2001
Dal 20-25 Maggio, 2001, questa conferenza è stata per la prima volta aperta a Durban, in Sud Africa. Si è parlato principalmente degli aspetti dell’Ittiologia nell’Indo-Pacifico (ad esempio: la sistematica, l’evoluzione, la genetica, l’ecologia, la biologia, il comportamento e la biogeografia). Si è svolto anche un simposio sui pesci di: oceano, acque profonde, chondrichthyan, larve, coste, estuari, barriera corallina e anche sui pesci acquario marino, sistematica dei pesci dell’Oceano Indiano occidentale, la diversità dei meccanismi di riproduzione dei pesci, la codifica dei pesci e la conservazione delle diversità di pesci delle zone marine protette dell’Indo-Pacifico. Ha partecipato anche Heiko ed ebbe modo di incontrare e di parlare con la leggendaria Marjorie Courtenay-Latimer (vedi sotto).
Marjorie Courtenay-Latimer insieme con Heiko Bleher. Ha apprezzato molto le pubblicazioni aqua, International Journal of Icthyology e aqua geõgraphia, vita sopra e sotto l’acqua. Mentre guardava le pubblicazioni ha detto: “Signor Bleher mi scusi, ma recente a causa dell’età mi si è abbassata la vita e devo usare gli occhiali” e li ha presi dalla sua borsa per metterli. Ha 94 anni. Qui di seguito un riassunto della sua straordinaria vita, comprese alcune informazioni sul fossile vivente, l’esemplare di Coelacanthus.
(Al momento è disponibile solo in inglese)
Marjorie Courtenay-Latimer and the coelacanth
This extraordinary woman born 24 February 1907 in East London, South Africa and who passed away on 17 May 2004 in her home town, probably was one of the most famous biologists already during live time, because of her discovery of the coelacanth. I was very fortunate to meet and talk to her lengthy during the 6th Indo-Pacific Conference (see photos) and I want to tell a little about her and the coelacanth.
She became the first curator of the East London Museum in South Africa, which opened in 1931, a museum with the only extant dodo egg. (The dodo, Raphus cucullatus, was a flightless bird endemic to Mauritius. Related to pigeons and doves, it stood about a meter tall and weighed about 20 kg, lived on fruit and nested on the ground. But it has been extinct since the mid-to-late 17th century. It is commonly used as the archetype of an extinct species because its extinction occurred during recorded human history, and was directly attributable to human activity.) In December of 1938 she identified the coelacanth, a fish thought to have been extinct for 70 million years. (Since then a number of populations have been discovered in out-of-the-way places.)
Courtenay-Latimer was already very early encouraged by her parents to follow a variety of non-traditional interests including ornithology, botany, and cultural history. As the first curator of the East London Museum she built its world-class collection from scratch, building on the Latimer family collection with specimens donated through her own investigations and through her network of contacts. In 1935, along with Eric Wilson, she excavated the fossil skeleton of the dicynodont Kannemeyeria simocephalus, a dinosaur of the Triassic period of key importance in the palacontological study of the southern African subregion. She was a founding member of the South African Museum’s Association, the Border Historical Society and the Border Wild Flower Association. In 1971 she received an honorary doctorate from Rhodes University. She was given the freedom of the city of East London in 1974. In 2003 clay casts of her footprints were placed in Heroes Park alongside those of icons Nelson Mandela and Walter Sisulu. And she remained professionally active, attending conferences and speaking at gatherings like the 6th Indo-Pacific Fish Conference in Durban, until the last year of her life. Latimer died at the age of 97, but her name became immortal with the coelacanth and its amazing discovery.
It was a few days before Christmas in 1938, a coelacanth was caught at the mouth of the Chalumna River on the east coast of South Africa. The fish was caught in a shark gill net by Captain Goosen and his crew, who had no idea of the significance of their find, but they thought the fish was bizarre enough to alert the local museum in the small South African town of East London. She was the Director of the East London Museum at the time and alerted the prominent South African ichthyologist J. L. B. Smith to this amazing discovery. The coelacanth was eventually named in her honour Latimeria chalumnae Smith, 1939. This discovery had led to the first documented population, off the Comoros Islands, between Africa and Madagascar and for about sixty years this was presumed to be the only coelacanth population in existence. But on 30 July 1998, a coelacanth was caught in a deep-water shark net by local fishermen off the volcanic island of Manado Tua in northern Sulawesi, Indonesia, about 10,000 km east of the Western Indian Ocean coelacanth population. The fisher brought the fish to the house of American biologist Mark Erdmann (who published recently with G. R. Allen an amazing work about the Indonesian Raja Ampat region in aqua Vol. 13 (3-4) see also ) . Mark, along with his wife Arnaz, had seen a specimen already in the outdoor markets the previous September and the local people were familiar with the coelacanth calling it raja laut or ‘king of the sea’.
When the coelacanth from Sulawesi was first documented, the only obvious difference between it and the coelacanth from the Comoros Islands was the colour. The Comoros Coelacanth is renowned for its steel blue colour, whereas fish from the Sulawesi population were reported to be brown. In 1999 the Sulawesi coelacanth was described as a new species, Latimeria menadoensis by Pouyaud, Wirjoatmodjo, Rachmatika, Tjakrawidjaja, Hadiaty and Hadie (without giving credit to Mark Erdmann).
Anyhow, the discovery of a new species of coelacanth in Sulawesi, opened up the possibility that coelacanths may be more widespread and abundant than was previously assumed.
In 2003 the IMS joined efforts with the African Coelacanth Project (ACEP) to search for coelacanths. On 6th September 2003 the first coelacanth was caught in the southern part of Tanzania at Songo Mnara making Tanzania the 6th country to record the presence of the L. chalumnae. Since then, 35 coelacanths have been recorded in Tanzania ranging from Tanga in the north, south to Mtwara. The Nungwi specimen is the 36th coelacanth to be caught in Tanzania and the first for Zanzibar. On 14th July 2007, a coelacanth was caught by fishermen off Nungwi, Northern Zanzibar. Researchers from the Institute of Marine Sciences, Zanzibar (IMS) led by Narriman Jiddawi were contacted and arrived on site to identify the fish as Latimeria chalumnae.
But the coelacanth specimen caught in 1938 is still considered to be the zoological find of the century. This ‘living fossil’ comes from a lineage of fishes that was thought to have been extinct since the time of the dinosaurs. Coelacanths are known from the fossil record dating back over 360 million years, with a peak in abundance about 240 million years ago. Before 1938 they were believed to have become extinct approximately 80 million years ago, when they disappeared from the fossil record. How could coelacanths disappear for over 80 million years and then turn up alive and well in the twentieth century? The answer seems to be that the coelacanths from the fossil record lived in environments favouring fossilisation. Modern coelacanths, both in the Comoros and Sulawesi were found in environments that do not favour fossil formation. They inhabit caves and overhangs in near vertical marine reefs, at about 200 m depth, off newly formed volcanic islands.
The discovery by science of the coelacanth in 1938 caused so much excitement because at that time coelacanths were thought to be the ancestors of the tetrapods (land-living animals, including humans). It is now believed that lungfishes are the closest living relative of tetrapods. The coelacanth may still provide answers to some very interesting evolutionary questions.
The coelacanth characteristics are quite different from all other living fishes. They have an extra lobe on the tail, paired lobed fins, and a vertebral column that is not fully developed. Coelacanths are the only living animals to have a fully functional intercranial joint, which is a division separating the ear and brain from the nasal organs and eye. The intercranial joint allows the front part of the head to be lifted when the fish is feeding. One of the most interesting features of the coelacanth, is that it has paired fins which move in a similar fashion to our arms and legs.
John E. Randall e Heiko Bleher due veterani, durante il 6° Indo-Pacifico Fish Conference a Durban, Sud Africa