A new species of caprellid, Aciconulatinggiensis (Amphipoda, Senticaudata, Caprellidae) was discovered from Pulau Tinggi, Sultan Iskandar Marine Park (SIMP), South China Sea, Malaysia. The new Malaysian species can be distinguished from the other Aciconula species by the combination of the following characters: 1. the presence of a very small suture between head and pereonite 1; 2. antenna 1 flagellum with 4 articles; 3. inner lobe of lower lip unilobed; 4. gnathopod 2 palm of propodus with a large proximal projection (stretching from the proximal margin of the palm to nearly mid-way of palm); 5. pereopods 3-4 with 2 articles (article 1 subrectangular, article 2 conical or tapering at the tip with 1 plumose seta and 2 normal setae) and; 6. pereopod 5 covered with relatively dense and long setae. An updated identification key for the five known species in the genus, including information on the respective geographical distribution and habitat, is presented.
Egg surface ornamentation, egg production rates, and hatching success of two calanoid copepod species (Acartia pacifica and Acartia cf. erythraea) were examined in a tropical coral reef of Tioman Island, Malaysia, near the equator (2°N). All observed females of A. pacifica and A. cf. erythraea produced eggs with spines on the surface, either short or long, which are common in resting eggs in temperate ecosystems that hatch when environmental conditions are favorable or after a certain refractory period. However, all of these spiny eggs in the present study hatched within 48 hours when exposed to ambient seawater temperature, suggesting that they were subitaneous eggs. Such spine ornamentation has been thought to be an adaptive feature only for resting eggs to survive during egg dormancy, but the presence of spines on subitaneous eggs suggests further possible functions of these spines such as reducing the risks of ingestion by predators.