As part of the EAPSI programme, Mr. Justin Havird gave a talk about his research done at the RMBR. Below is a summary of his work.
Taxonomic diversity of the teleost family Cobitidae in Southeast Asia
Fishes compose about 30,000 of the estimated 60,000 species of vertebrates on earth, or roughly half of the planet’s vertebrate diversity. Teleosts (bony fishes with a mobile premaxilla) account for the majority of this diversity and represent some of the planet’s most scientifically, economically, and culturally important animals. Despite intense efforts to describe teleost diversity in North America, it is thought that many (if not the majority) species of teleosts remain unknown to the scientific community. This seems realistic as hundreds of new species of teleosts are described each year, mainly from areas that have not been historically sampled. Southeast Asia represents one area that remains to be adequately examined.
Therefore, the goal of my EAPSI research project this summer was to more closely examine members of the teleost family Cobitidae (order Cypriniformes) from SE Asia. These fishes include the minnows, carps, and loaches and were recently show to represent a monophyletic group (meaning that they are a natural grouping based on common ancestry). These fishes were studied using 5 main research techniques: 1) Collecting proposed new species in the genus Lepidocephalichthys from Thailand 2) Collecting additional cobitids from regions around Singapore 3) Examining the vast diversity of cobitid specimens housed at the Raffles Museum of Biodiversity Research (RMBR) at the National University of Singapore 4) Studying loach behavior by examining mating in the royal mini loach (Kottelatlimia pristes) and 5) Using molecular techniques to examine species and genus relationships in Cobitidae, especially with respect to the new species. In these ways, live Cobitids would be studied in their natural environment and in aquaria, preserved specimens would be examined in the museum, and molecular data would be generated in a molecular biology laboratory.
Field collections in Thailand and Southern Malaysia were made over a 3 week period using standard sampling techniques (e.g., seining, dip netting, electroshock, etc.). Habitats sampled included mountainous and lowland streams and rivers, swamps, rice paddy fields, ponds, and lakes. Museum specimens from the RMBR were measured and examined under a dissecting microscope to account for morphometric, meristic, and color variation. Specimens were also photographed to generate a visual catalogue of the RMBR’s cobitid collection. Behavior was to be catalogued using a Hyndman index (+/- scoring) in 2 hour blocks for a group of ~30 loaches in an approximate 50/50 sex ratio. However, due to the lack of available aquarium specimens in SE Asia during the study period, this portion of the research was not able to be completed during the summer program. RAG-1 and cytocrome c oxidase genes were to be sequenced from the new species and other cobitids collected and then species relationships were to be examined by generating maximum likelihood and Bayesian phylogenies based on our novel sequences and existing cobitid sequences, however due to logistics (long mail time) this was also not possible.
Based on museum collections and our new collections from Thailand, two new species in the genus Lepidocephalichthys were collected during this study. One is diagnosed by the presence of scales on the top of the head and the other is diagnosed by a very large and irregular flange found on the pectoral fins of males. Immediate future studies include performing the proposed molecular work and including all cobitids collected in Thailand and Malaysia.