Dear Colleagues, We are excited to share our newest publications on the Deraniyagala's beaked whale (Mesoplodon hotaula): 01). Wenzhi Lin#, Hui Kang#, Inge Seim, Binshuai Liu, Shenglan Chen, Mingming Liu, Lijun Dong, Mingli Lin, Mingyue Ouyang, Xiaoyu Huang, Yingxue Gao, Zixin Yang, Yaolei Zhang, Jiahao Wang, Guangyi Fan, Songhai Li*. (2024) The first genetically confirmed live sighting of the Deraniyagala's beaked whale (Mesoplodon hotaula), with insights into the diversity, phylogeny, and past demographic history. Marine Mammal Science. e13180. https://doi.org/ 10.1111/mms.13180. Abstract: Beaked whales have recently been reported in the South China Sea but with taxonomic uncertainty due to their ambiguous morphological features. Here, we sequenced three genetic markers, the control region (CR) and cytochrome b (cytb) of the mitochondrial genome and the first intron of the nuclear muscle actin gene ACTA2, of two biopsy samples collected in 2021, and revealed unambiguous clustering with sequences previously attributed to Deraniyagala's beaked whale (Mesoplodon hotaula). Phylogenetic analysis of complete mitogenomes strongly supported the close relationship between the Deraniyagala's beaked whale and the ginkgo-toothed beaked whale (M. ginkgodens). Whole-genome sequencing suggested a high degree of heterozygosity in the Deraniyagala's beaked whale. Ancient inbreeding may have had a greater impact than the recent inbreeding on Deraniyagala's beaked whales, but more samples are needed to draw a firm conclusion. The approximate effective population size of Deraniyagala's beaked whale was found lowest among seven examined ziphiids, which has been experiencing a steady decline since 300,000 ya. Therefore, we suggest that the conservation status of Deraniyagala's beaked whales should be assessed when essential information is available. The results of our study provide genetic evidence of the live sighting of Deraniyagala's beaked whale in the South China Sea and are fundamental to understanding the morphological, behavioral, and ecological perspectives of this cetacean species. 02). Lijun Dong, Yuhang Song, Wenzhi Lin, Mingming Liu, Mingli Lin, Songhai Li*. (2024) Echolocation signals recorded in the presence of Deraniyagala's beaked whales (Mesoplodon hotaula) in the western Pacific (South China Sea) indicate species-specificity and intraspecific variation. Marine Mammal Science. e13179. https:// doi.org/10.1111/mms.13179. Abstract: Deraniyagala's beaked whale (Mesoplodon hotaula) is one of the least-known beaked whale species, with only a few of possible live sightings being documented to date. Here, vocalizations of Deraniyagala's beaked whales were recorded using drifting recording systems in the confirmed presence of this whale in the northern South China Sea (SCS) in 2021. A total of 699 qualified frequency-modulated (FM) pulses were used to calculate frequency and duration measurements. FM pulses had a median peak frequency of 43.3 kHz and median interpulse interval (IPI) of 244.6 ms. Both the spectra measurements and clustering analysis showed the recorded clicks closely resemble the clicks of beaked whales at Palmyra Atoll (presumed to belong to Deraniyagala's beaked whale). Compared with other Ziphiidae species, interspecific differences were also observed. Distinguishing between Deraniyagala's and ginkgo-toothed (M. ginkgodens) beaked whales with acoustic data sets seems to prove feasible. Our results also suggested that Deraniyagala's beaked whales may produce more than one subtype of FM pulses. This study presents the first description of echolocation clicks produced by this species based on the confirmed visual sightings. It is beneficial to identify the species in passive acoustic monitoring records and gain further insight into this species' vocalizations. 03). Mingming Liu, Wenzhi Lin, Binshuai Liu, Shenglan Chen, Mingli Lin, Lijun Dong, Hui Kang, Mingyue Ouyang, Zixin Yang, Xiaoyu Huang, Massimiliano Rosso, L. Todd Pusser, John Y. Wang, Robert L. Pitman*, Songhai Li*. (2024) Observations on Deraniyagala's beaked whale (Mesoplodon hotaula) in the South China Sea based on the first confirmed live sightings. Marine Mammal Science. e13178. <https://doi.org/10.1111/mms.13178> https://doi.org/10.1111/mms.13178. Abstract: Deraniyagala's beaked whale, Mesoplodon hotaula, was previously known from eight published strandings and no confirmed live sightings, making it one of the least-known cetaceans. We conducted six cetacean survey cruises in the South China Sea between 2019 and 2023, and during 120 sea-days we recorded 12 sightings of unidentified Mesoplodon. From biopsy samples and acoustic recordings, five sightings were subsequently confirmed as M. hotaula. Using photographs, we provide the first field descriptions and observations of this species. The calf/juvenile has a distinctive facial coloration and dorsal striping pattern that appear to be diagnostic among Indo-Pacific Mesoplodon; among adult males, the dark rostrum of M. hotaula and the distinctively white-tipped beak of ginkgo-toothed beaked whale, M. ginkgodens, distinguish these similar-looking, partially sympatric species. Mean group size was small (3.0, n = 5), with a preference for deep (2,156 m, n = 5), warm (30.3C, n = 3) water. We update the known distribution of this species, present evidence of fishery interactions, and document the first reported mixed-species Mesoplodon group: a juvenile Blainville's beaked whale M. densirostris associated with four M. hotaula. These sightings identify the South China Sea as a potentially important area for this almost completely unknown species. Please email me at lish@idsse.ac.cn <mailto:lish@idsse.ac.cn> if you have any questions. Best Regards Songhai ------------------------------------------------------------------- Songhai Li Ph.D. & Prof. Marine Mammal and Marine Bioacoustics Laboratory Institute of Deep-sea Science and Engineering Chinese Academy of Sciences 28 Luhuitou Road, Sanya, 572000, China Phone: +86-898-88222393 Email: <mailto:lish@sidsse.ac.cn> lish@idsse.ac.cn <http://www.idsse.cas.cn/yjsgk2015/zzjg2015/yftx2015/shkxyjb2015/hybrdwyhysw sxyjz2015/> http://www.idsse.cas.cn/yjsgk2015/zzjg2015/yftx2015/shkxyjb2015/hybrdwyhysws xyjz2015/ <http://www.cetacean.csdb.cn/> http://www.cetacean.csdb.cn/