The Taiwanese and Philippine Species of the Terrestrial Crabs Bresedium Serène and Soh, 1970 and Sesarmops Serène and Soh, 1970 (Crustacea: Decapoda: Brachyura), with Descriptions of Two New Species

© 2020 Academia Sinica, Taiwan Open Access The Taiwanese and Philippine Species of the Terrestrial Crabs Bresedium Serène and Soh, 1970 and Sesarmops Serène and Soh, 1970 (Crustacea: Decapoda: Brachyura), with Descriptions of Two New Species Jheng-Jhang Li1,2, Hsi-Te Shih3,*, and Peter K. L. Ng4 1Department of Marine Biotechnology and Resources, National Sun Yat-sen University, 70, Lianhai Road, Kaohsiung 80424, Taiwan 2East Peak Ecological Consultants, Inc., 22, Wanggong Road, Linyuan Dist., Kaohsiung 83249, Taiwan 3Department of Life Science and Research Center for Global Change Biology, National Chung Hsing University, 250, Kuo Kuang Road, Taichung 402, Taiwan. *Correspondence: E-mail: [email protected] 4Lee Kong Chian Natural History Museum, National University of Singapore, 2 Conservatory Drive, Singapore 117377, Republic of Singapore Received 7 January 2020 / Accepted 21 April 2020 / Published 25 May 2020 Communicated by Benny K.K. Chan The genera Bresedium Serène and Soh, 1970 and Sesarmops Serène and Soh, 1970 are two closely related taxa inhabiting terrestrial or freshwater environments from the Indo-West Pacific. Based on morphological and molecular evidence, two new species from Taiwan, the Philippines and Indonesia are described in this study, viz. B. eurypleon n. sp. and S. mora n. sp. The new species can be distinguished from congeners by a suite of carapace, chelipedal, gonopodal and vulvar characters. Bresedium philippinense (Rathbun, 1914) is here shown to be a junior synonym of B. brevipes (De Man, 1889). A poorly known Philippine species, Sesarmops mindanaoensis (Rathbun, 1914), is redescribed from the type and fresh material, and is recorded for the first time from Taiwan. Key words: Taxonomy, New species, Bresedium eurypleon, B. philippinense, Sesarmops mora, S. mindanaoensis, Morphology, Mitochondrial 16S rDNA, Cytochrome oxidase subunit I. Citation: Li JJ, Shih HT, Ng PKL. 2020. The Taiwanese and Philippine species of the terrestrial crabs Bresedium Serène and Soh, 1970 and Sesarmops Serène and Soh, 1970 (Crustacea: Decapoda: Brachyura), with descriptions of two new species. Zool Stud 59:16. doi:10.6620/ ZS.2020.59-16. BACKGROUND Most sesarmid crabs (family Sesarmidae Dana, 1851) are common and important in mangrove regions; they are able to tolerate high temperatures and salinity fluctuations and have been the subject of many recent ecological studies (e.g., Lee 2015; YF Li et al. 2017; Theurkauff et al. 2018). Serène and Soh (1970: 391, 399, 400) established two new genera, Bresedium and Sesarmops, for several Indo-West Pacific species previously placed in Sesarma Say, 1817. Members of Bresedium are diagnosed by the lateral margins of the carapace being subparallel and the carapace appearing rectangular in shape, the male pleon has the telson distinctly inserted into the concave distal margin of somite 6, and the distal part of the male first gonopod is elongated and slender (Serène and Soh 1970). Species of Sesarmops are characterised by having a carapace that is as long as or longer than the exorbital width, the lateral margins of the carapace are prominently divergent posteriorly with the carapace appearing trapezoidal, the male pleon has an almost straight or only gently concave distal margin of somite 6 in which the telson is inserted, and the distal part of the male first gonopod is less elongate (Serène and Soh 1970). Ng et al. (2008) commented that Bresedium and Sesarmops are sister taxa based on unpublished morphological and molecular data, and that some Zoological Studies 59:16 (2020) doi:10.6620/ZS.2020.59-16 1 © 2020 Academia Sinica, Taiwan species of Sesarmops do not belong to that genus. They commented that Sesarmops intermedius (De Haan, 1835), S. sinensis (H. Milne Edwards, 1853) Chiromantes dehaani (H. Milne Edwards, 1853) and some species of Pseudosesarma Serène and Soh, 1970 were actually closer to each other than with genera they had been placed with, and the generic system of these species need to be revised (Ng et al. 2008: 223). Three species of the two genera have been recorded from Taiwan: the widely distributed Bresedium brevipes (De Man, 1889), Sesarmops impressus H. Milne Edwards, 1837 and Sesarmops intermedius (De Haan, 1835) (see Ng et al. 2017). Three species have previously been recorded from the Philippines: Sesarmops impressus H. Milne Edwards, 1837, Sesarmops mindanaoensis (Rathbun, 1914) and Bresedium philippinense (Rathbun, 1914), the latter two of which are only known from their type localities of Mindanao and Busuanga Islands, Palawan, respectively (Rathbun 1914). The present study focuses on the taxonomy of a number of poorly known and new Bresedium and Sesarmops species collected from Taiwan and the Philippines. As part of this study, we describe a new species of Bresedium as well as a new species of Sesarmops, both of which can be distinguished from congeners by a suite of carapace, chelipedal, gonopodal and vulvar characters. The morphological differences are also supported by molecular evidence from the 16S rDNA and cytochrome c oxidase subunit I (COI), which have been used extensively for the taxonomy and phylogeny of crabs (Chu et al. 2015), including the Sesarmidae (e.g., Cannicci et al. 2017; Shahdadi et al. 2017 2018a b; Li et al. 2019; Shih et al. 2019). In order to describe these two species, we also had to clarify the identities of Sesarmops mindanaoensis and Bresedium philippinense, and the types of both species were examined. Bresedium philippinense is proved to be a junior synonym of Sesarma brevipes; Sesarmops mindanaoensis is a distinct taxon. MATERIALS AND METHODS Specimens examined were deposited in the Biodiversity Research Museum, Academia Sinica, Taipei, Taiwan (ASIZ); Zoological Collections of the Department of Life Science, National Chung Hsing University, Taichung, Taiwan (NCHUZOOL); Naturalis Biodiversity Centre (previously the Rijksmuseum van Natuurlijke Historie), Leiden, The Netherlands (RMNH); U.S. National Museum of Natural History, Smithsonian Institution, Washington, D.C., U.S.A. (USNM); and Zoological Reference Collection of the Lee Kong Chian Natural History Museum, National University of Singapore (ZRC). Measurements provided are of the maximum carapace width (CW) and carapace length (CL) in millimetres. The abbreviations G1 and G2 are used for the male first and second gonopods, respectively. The abbreviations P2–P5 are used for the second to fifth pereiopods (first to fourth ambulatory legs), respectively. Measurements of ambulatory legs follow Maenosono and Naruse (2015). The terminology used follows Guinot et al. (2013) and Davie et al. (2015). Sequences of the mitochondrial 16S rDNA and COI were obtained following the method described by Shih et al. (2016), after verification with the complimentary strand. Sequences of the different haplotypes have been deposited in the DNA Data Bank of Japan (DDBJ) (accession numbers in Table 1). Other species with similar morphology were included to confirm the phylogenetic relationships among related taxa (Table 1). For the combined 16S and COI dataset, the bestfitting models for sequence evolution of individual datasets were determined by PartitionFinder (vers. 2.1.1, Lanfear et al. 2017), selected by the Bayesian information criterion (BIC). The best models obtained were both GTR+I+G and were subsequently applied to the partitioned Bayesian inference (BI) analysis. The BI was performed with MrBayes (vers. 3.2.6, Ronquist et al. 2012). The search was run with 4 chains for 10 million generations and 4 independent runs, with trees sampled every 1000 generations. The convergence of chains was determined by the average standard deviation of split frequency values below the recommended 0.01 (Ronquist et al. 2005) and the first 1100 trees were discarded as burnin. The maximum likelihood (ML) analysis was conducted in RAxML (vers. 7.2.6, Stamatakis 2006). The model GTR + G (i.e., GTRGAMMA) was used with 100 runs; the best ML tree was found by comparing the likelihood scores. The robustness of the ML tree was evaluated by 1,000 bootstrap pseudoreplicates under the model GTRGAMMA. RESULTS TAXONOMY Sesarmidae Dana, 1851 Bresedium Serène and Soh, 1970 Type species: Sesarma edwardsii brevipes De Man, 1889, by original designation. page 2 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan Table 1. Haplotypes of 16S and COI genes of Sesarmidae specimens used in study. For abbreviations, see MATERIALS AND METHODS Species Locality Sample size Catalogue no. of NCHUZOOL (unless indicated) Haplotype of 16S and COI Access. no. of 16S Access. no. of COI Bresedium brevipes Taiwan: Gangkou, Pingtung 1 15549 Bb1 LC537760 LC537802 Philippines: Bohol 2 15555 Bb2 LC537761 LC537803 Indonesia: Bali 1 15556 Bb3 LC537762 LC537804 Australia: Queensland 1 ZRC 2009.0901 Bb4 LC537763 LC537805 Bresedium eurypleon n. sp. Taiwan: Houwan, Pingtung 1 15557 Be1 LC537764 LC537806 Taiwan: Houwan, Pingtung 1 15558 Be2 LC537765 LC537807 Taiwan: Houwan, Pingtung 1 15831 Be3 LC537766 LC537808 Philippines: Guimaras I. 1 ZRC 2017.0478a Be4 LC537767 LC537809 Chiromantes dehaani Japan: Bonin Islands 1 ZRC 2013.0173 (paratype of C. magnus) Cd1 LC537768 LC537810 Japan: Kagoshima 1 ZRC 2012.0057 Cd2 LC537769 LC537811 Japan: Kumejima, Ryukyus 1 ZRC Cd3 LC537770 LC537812 Japan: Ishigaki, Ryukyus 1 15563 Cd4 LC537771 LC537813 Taiwan: Wunliao, Taichung 1 15566 Cd5 LC500752 LC500772 Taiwan: Wunliao, Taichung 1 15561 Cd6 LC500752 LC500771 Taiwan: Gaomei, Taichung 1 15565 Cd7 LC500753 LC500773 China: Shanghai 1 ZRC 2010.420 (as C. neglectum) Cd8 LC537772 LC537814 China: Guangzhou, Guangdong 1 15564 Cd9 LC500752 LC500774 Pseudosesarma bocourti Malaysia: Tioman 1 15866 Pb LC537773 LC537815 Pseudosesarma crassimanum purchased 2 15867 Pc LC537774 LC537816 Pseudosesarma edwardsii Malaysia: Langkawi 1 16332 Pe1 LC537775 LC537817 Singapore 1 ZRC 2003.0084 Pe2 LC537776 LC537818 Pseudosesarma patshuni China: Yangjiang, Guangdong 1 15740 Pp LC500765 LC500790 Sesarmops impressum 1 Madagascar: Mosoala Peninsula; Mayotte 2 ZRC 2010.0302; ZRC 2011.0005 Sim1 LC537777 LC537819 Madagascar 1 MNHN.IV.2019.4522 Sim2 LC537778 LC537820 Mayotte 1 MNHN.IV.2009.953 Sim3 LC537779 LC537821 Sesarmops impressum 2 Taiwan: Hualien 1 15868 Sima1 LC537780 LC537822 Taiwan: Lanyu, Taitung 1 15869 Sima2 LC537781 LC537823 Taiwan: Gangkou, Pingtung 1 15870 Sima2 LC537782 LC537824 Philippines: Guimaras 1 ZRC 2017.0477 Sima3 LC537783 LC537825 Philippines: Camiguin 1 15871 Sima4 LC537784 LC537826 Philippines: unknown locality 1 ASIZ Sima5 LC537785 LC537827 Indonesia: Sulawesi 1 ZRC 2016.0252 Sima6 LC537786 LC537828 Sesarmops intermedius Japan: Kyushu 1 ZRC 2013.0140 Sin1 LC537787 LC537829 Japan: Amami, Ryukyus 1 15873 Sin2 LC537788 LC537830 Japan: Kumejima, Ryukyus 1 ZRC Sin3 LC500766 LC500791 Japan: Kumejima, Ryukyus 1 ZRC Sin4 LC537789 LC537831 Japan: Iriomote, Ryukyus 1 15741 Sin3 LC500766 LC500791 Taiwan: Aodi, New Taipei City 1 15872 Sin5 LC537790 LC537832 Taiwan: Hualien 1 15742 Sin6 LC500766 LC500791 Taiwan: Houwan, Pingtung 1 15743 Sin3 LC500766 LC500792 Taiwan: Gangkou, Pingtung 2 15874 Sin3 LC537791 LC537833 China: Shanghai 1 ZRC 2010.0421 (id. as S. sinensis) Sin7 LC537792 LC537834 China: Linhai, Zhejiang 1 15676 (id. as S. sinensis) Sin7 LC537793 LC537835 China: Xiapu, Fujian 1 15875 (id. as S. sinensis) Sin8 LC537794 LC537836 Sesarmops mindanaoensis Taiwan: Gangkou, Pingtung 1 15858 Smi LC537795 LC537837 Philippines: Kawasan, Cebu 1 16333 Smi LC537796 LC537838 Philippines: Kawasan, Cebu 1 ZRC 2019.1657 Smi LC537797 LC537839 Taiwan: Gangkou, Pingtung 1 15858 Smi LC537798 LC537840 Sesarmops mora n. sp. Taiwan: Gangkou, Pingtung 1 15865 Smo1 LC537799 LC537841 Philippines: Cebu 1 ZRC 2012.0434 Smo2 LC537800 LC537842 Philippines: Cebu 1 ASIZ Smo1 LC537801 LC537843 Total 53 page 3 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan Remarks: Bresedium Serène and Soh, 1970, was established with Sesarma edwardsii brevipes De Man, 1889, as the type species, and currently contains three taxa, viz. B. brevipes (De Man, 1889), B. philippinense (Rathbun, 1914), and B. sediliense (Tweedie, 1940). Members of the genus were characterised by Serène and Soh (1970) as having a carapace broader than long and not prominently inflated, the lateral margin has two epibranchial teeth behind the external orbital tooth, the basal antennular article is at least twice as broad as long, the upper surface of the male palm is without distinct pectinated crest(s), the inner surface of the palm has a prominent vertical row of granules, the ambulatory legs are not elongated, the male telson is deeply inserted into the distal margin of pleonal somite 6, and the distal chitinous part of the G1 is elongate and slender. In many respects, Bresedium closely resembles members of Sesarmops, some species (notably S. impressus) which also possess a male telson which is inserted into the distal margin of pleonal somite 6 and possess an elongate distal chitinous part of the G1. Of the three species, B. sediliense is easily distinguished by having the dactylus of the male cheliped as long as the height of palm, and the G1 distal chitinous process is relatively broad, shorter, and bent obliquely, with the tip just visible externally when the telson is closed (cf. Tweedie 1940; present material). On the other hand, B. brevipes has proportionately longer dactylar fingers (longer than height of the palm), with the distal chitinous process of the G1 is slender, relatively longer, straight, in line with the rest of the G1 and the tip is not distinctly bent and completely hidden by the closed telson. Serène and Soh (1970: 399) suspected B. philippinense was a species of Bresedium but could not be sure. Ng et al. (2008: 223) confirmed that it belonged to the genus and treated it as a distinct species. Bresedium brevipes and B. philippinense are very similar and their taxonomy has been unclear, mainly because the type of B. philippinense was only briefly described and has never been figured. The reexamination of the type male of B. philippinense as well as a good series of specimens from the Philippines now shows it is actually a junior synonym of B. brevipes. Bresedium sediliense (Tweedie, 1940) from Peninsular Malaysia is distinct from the other two species in that the dactylus of the chela is as long as the height of the palm (Tweedie 1940: 8b) and the elongate chitinous distal part of the G1 is inserted at an angle to the main shaft (Tweedie 1940: 8b). Bresedium brevipes (and B. philippinense) has the dactylus of the chela longer than the height of the palm (Figs. 2F, 3G) and the chitinous distal part of the G1 is proportionately longer and continues in a straight line with the main shaft (Figs. 5, 6E–K). The present paper will only deal with the taxonomy of Bresedium brevipes and B. philippinense as only they are present in Taiwan and the Philippines. The taxonomy of B. sediliense will be discussed in greater depth by CD Schubart and PKL Ng in an ongoing revision of these and other genera. Bresedium brevipes (De Man, 1889) (Figs. 1–6) Sesarma edwardsii – De Man 1887: 649; De Man 1888: 185 pl. 13 (1–4). (not Sesarma edwardsii De Man, 1888). Sesarma edwardsii var. brevipes De Man, 1889: 425 (Sydney, Australia); De Man 1890: 94 (no locality); De Man 1892: 330 (Flores). Sesarma edwardsii var. breviceps (sic) – Bürger 1893: 617 (Philippines). Sesarma (Episesarma) edwardsi var. brevipes – De Man 1895: 173 (Atjeh, Sumatra, Indonesia). Sesarma (Sesarma s. s.) edwardsi var. brevipes – De Man 1902: 509 (Ternate, Batjan, Halmahera, Indonesia). Sesarma (Sesarma s. s.) edwardsi philippinense Rathbun, 1914: 76 (Busuanga Island, Philippines); Tesch 1917: 148 (list). Sesarma (Sesarma s. s.) edwardsii brevipes – Tesch 1917: 147 (Batjan, Indonesia). Sesarma (Sesarma) brevipes – Serène 1968: 105 (list). Sesarma (Sesarma) brevipes philippinensis – Serène 1968: 105 (list). Bresedium brevipes – Serène and Soh 1970: 399 (taxonomy); Davie 2002: 220 (list); Ng et al. 2008: 220 (list); Koller et al. 2010: 366 (Taiwan); Li and Chiu 2013: 38, 3 unnumbered figs (Taiwan); Li and Chiu 2019a: 14, 2 unnumbered figs. (Taiwan); Li and Chiu 2019b: 58, 3 unnumbered figs (Taiwan). Bresedium philippinensis – Serène and Soh 1970: 399 (discussion). Bresedium philippinense – Ng et al. 2008: 220 (list). Material examined: Holotype (Sesarma (Sesarma) edwardsi philippinense Rathbun, 1914), male (16.7 × 14.5) (USNM 45750), Pangauran R., Busuanga Island, Palawan, Philippines. Others: Australia: 2 females (16.8 × 14.8, 15.3 × 13.3) (RMNH D1210), “Australia, New South Wales, Sydney”, coll. Museum Godeffroy; 2 males (25.0 × 21.8, 24.0 × 21.3) (ZRC 2009.0901), Flame Tree Creek, between Arlie Beach and Shute Harbour, Brisbane, Queensland, coll. J. W. Shaif and A. Humpherys, 2 June 1997. Philippines: Kawasan, Cebu: 8 males (18.4 × 15.5, 17.3 × 15.3, 15.9 × 13.4, 15.0 × 12.8, 15.7 × 13.8, 13.7 × 11.8, 13.5 × 11.7, 11.4 × 10.0), 2 females (21.1 × 17.7, 14.5 × 13.0) (ASIZ 1125), coll. H.-C. Liu, 25 November 2001; 13 males (largest 24.7 × 21.0), 1 ovigerous female (19.7 × 16.8), 7 females (ZRC 2019.1667), coll. P. K. L. Ng, 4 December 2001; 4 males (20.0 × 16.7, 18.4 × 15.7, 15.8 × 13.4, 12.6 × 11.2), 4 females (22.0 × 18.8, 16.3 × 13.8, 15.3 × 13.3, 10.9 × 9.2) (ASIZ 1204), coll. H.-C. Liu, 4 December 2001; 5 males (25.7 × 21.9, 25.6 × 21.7, 24.4 × 21.3, 25.1 × 21.5, 22.6 × 19.3) (ZRC 2016.0667), coll. N. K. Ng et al., 2 January 2002; 4 females (12.7 × 11.0, 11.2 × 9.3, 11.8 × 10.1, 9.8 × 8.4) (ASIZ), coll. H.- page 4 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan C. Liu, 15 February 2003; Loboc R., Bohol: 3 males (16.4 × 14.0, 17.4 × 14.9, 18.9 × 15.7), 3 females (12.2 × 9.7, 15.6 × 13.4, 17.3 × 15.0), 2 ovigerous females (14.3 × 12.1, 17.9 × 17.6), NCHUZOOL 15555, coll. 26 September 2003. Taiwan: Gangkou R. estuary, Pingtung: 1 female (13.9 × 12.0) (ZRC 2019.1644), coll. J.-J. Li, 13 July 2012; 1 female (16.9 × 14.3) (ZRC 2019.1643), coll. J.-J. Li, 15 July 2012; 1 male (17.3 × 14.9), 1 female (16.3 × 13.3) (NCHUZOOL 16325), coll. J.-J. Li, 10 October 2014; 1 female (14.1 × 12.3) (ZRC 2019.1645), coll. J.-J. Li, 24 September 2015; 1 female (14.9 × 12.7) (ZRC 2019.1642), coll. J.-J. Li, 9 December 2015; 1 female (15.3 × 13.3) (NCHUZOOL 16320), coll. J.-J. Li, 20 June 2016; 1 female (20.0 × 16.8) (NCHUZOOL 16323), coll. J.-J. Li, 22 June 2016; 1 male (21.7 × 19.5) (NCHUZOOL 15549), 2 males (22.4 × 19.5, 22.0 × 19.0), 1 female (19.3 × 16.7) (NCHUZOOL 16324), 2 females (21.0 × 17.7, 19.6 × 16.5) (NCHUZOOL 16326), 1 male (21.1 × 17.8), 1 female (24.6 × 21.7) (ZRC 2019.1641), coll. J.-J. Li, 18 Fig. 1. Bresedium brevipes (De Man, 1889), in situ photographs in Taiwan. A, male (specimen not collected), Gangkou R. downstream, south bank, Pingtung, 13 January 2011; B, female (18.0 × 15.5 mm) (NCHUZOOL 16329), Gangkou R. downstream, south bank, Pingtung; C, male (17.9 × 15.5 mm) (ZRC 2019.1646), Gangzai R. estuary north bank, Pingtung; D, female (specimen not collected), Gangkou R. estuary, north bank, Pingtung, 4 July 2011; E, male (specimen not collected), Gangkou R. estuary, north bank, Pingtung, 13 July 2014; F, female (specimen not collected), Gangkou R. downstream, south bank, Pingtung, 13 January 2011. page 5 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan May 2017; 2 males (22.3 × 18.9, 20.2 × 18.4), 1 female (20.5 × 17.8) (NCHUZOOL 16318), coll. J.-J. Li, 5 June 2017; 1 male (20.7 × 17.9), 1 female (21.0 × 18.3) (NCHUZOOL 16322), coll. J.-J. Li, 6 July 2017; 1 male (13.5 × 11.9) (NCHUZOOL 16321), coll. J.-J. Li, 7 July 2017; 1 male (18.8 × 16.3) (NCHUZOOL 16319), coll. J.-J. Li, 17 July 2017; 4 males (23.8 × 21.2, 20.9 × 18.7, 19.6 × 17.4, 19.4 × 17.3), 3 females (21.9 × 18.5, 17.4 × 14.8, 15.8 × 13.8) (NCHUZOOL 16327), 2 females (21.6 × 18.9, 16.3 × 14.0) (ZRC 2019.1651), coll. J.-J. Li, 11 August 2017; 4 males (23.5 × 20.3, 21.9 × 19.6, 20.5 × 18.5, 17.3 × 15.2), 4 females (28.4 × 27.5, 27.2 × 26.9, 19.8 × 17.3, 17.7 × 15.1) (NCHUZOOL 16328), coll. J.-J. Li, 30 October 2017; 1 female (19.3 × 17.4) (NCHUZOOL 16317), coll. J.-J. Li, 20 April 2018; Gangzai R. estuary, Pingtung: 1 male (17.9 × 15.5) (ZRC 2019.1646), coll. J.-J. Li, 16 June 2012; Meilun R. estuary, Hualien: 2 males (21.4 × 18.4, 13.7 × 12.2) (ZRC 2008.0876), coll. H.-C. Liu, 2 December 2000; 1 female (14.7 × 13.2) (ZRC 2019.1648), coll. J.-J. Li, 28 July 2012; 1 male (13.7 × 11.4) (ZRC 2019.1649), 1 female (14.4 × 14.1) (ZRC 2019.1647), coll. J.-J. Li, 3 March 2015; 1 male (15.4 × 13.7) (ZRC 2019.1650), coll. J.-J. Li, 25 July 2015; 1 female (18.0 × 15.5) (NCHUZOOL 16329) coll. J.-J. Li, 3 August 2017. Indonesia: 1 male (22.2 × 19.1) (RMNH D1195), Batjan Island, Moluccas, coll. Kükenthal Expedition, 1893–94; 1 male (5.8 × 5.1) (NCHUZOOL 15556), Bali, Indonesia, coll. H.-T. Shih, 22 July 2014. Diagnosis of male: Carapace (Figs. 2A, D, 4A, D, G) square in dorsal view, 1.1 ± 0.1 times broader than long (n = 14); regions well defined, separated by shallow grooves; postfrontal region distinct, separated into 4 lobes by deep grooves; front deflexed Fig. 2. Bresedium brevipes (De Man, 1889), life colouration. A, B, male (20.5 × 17.8 mm) (NCHUZOOL 16318), Gangkou R., Taiwan; C, male (17.9 × 15.5 mm) (ZRC 2019.1646), Gangzai R., Taiwan; D–F, male (25.1 × 21.5 mm) (ZRC 2016.0667), Kawasan, Cebu, Philippines. A, D, overall dorsal view; B, C, ventral view of cephalothorax; E, frontal view of cephalothorax; F, outer view of left chela. page 6 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan Fig. 3. Bresedium brevipes (De Man, 1889). A, female (15.3 × 13.3 mm) (RMNH D1210), “Sydney”, Australia; B, D, male (25.0 × 21.8 mm, 24.0 × 21.3 mm) (ZRC 2009.0901), Brisbane, Australia; C, E, F, male (16.7 × 14.5 mm) (USNM 45750) (holotype of Sesarma (Sesarma) edwardsi philippinense Rathbun, 1914), Philippines; G, H, male (17.9 × 15.5 mm) (ZRC 2019.1646), Gangzai R., Taiwan; I, female (14.1 × 12.3 mm) (ZRC 2019.1645), Gangzai R., Taiwan. A–C, overall dorsal view; E, dorsal view of carapace; D, F, ventral view of anterior thoracic sternum and pleon; G, I, outer view of left chela; H, dorsal view of left chela. page 7 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan Fig. 4. Bresedium brevipes (De Man, 1889). A–C, male (22.2 × 19.1 mm) (RMNH D1195), Batjan Island, Indonesia; D–F, male (21.3 × 18.5 mm) (ZRC 2019.1667), Taiwan; G–I, male (24.7 × 21.0 mm) (ZRC), Philippines. A, D, G, right side of carapace; B, E, H, left third ambulatory leg; C, male pleonal somites 3–6 and telon; D, E, male pleonal somites 5, 6 and telson. Scale bars = 1.0 mm. page 8 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan downwards, margin distinctly concave in dorsal view. Anterolateral margin with large triangular, exorbital angle and smaller, triangular epibranchial tooth; lateral margin straight, slightly divergent posteriorly (Fig. 4A). Cornea reaching edge of external orbital tooth. Chelipeds (Figs. 2F, 3G, H) robust, outer surface with numerous rounded granules; dactylus dorsal margin with numerous chitinous granules; proximal part of fixed-finger slightly concave. Ambulatory legs (Figs. 4B, E, H, 6A–D) stout; P3 and P4 subequal, longer than others, about 1.4 ± 0.1 times carapace width (n = 14). P3 merus 2.2 ± 0.2 times as long as broad (n = 7); upper margin with acute subdistal spine. Propodus of P3 2.2 ± 0.2 times as long as broad (n = 7), with accessory stria on inferior proximal portion of outer surface, dorsal and ventral margins with short stiff setae. Dactylus of P3 0.6 ± 0.1 times length of propodus (n = 7), slightly curved, terminating in acute calcareous tip; dorsal and ventral margins with short stiff setae. Pleon (Figs. 2B, C, 4C, F, I) relatively broad, all somites free. Telson semicircular, evenly rounded, as long as preceding somite, base of telson deeply inserted in somite 6. G1 (Figs. 5, 6E–K) straight, apical part chitinous, forming elongate slim process, bent at an angle of 35º–45º, ending in truncate tip. Female: Carapace broader than male, 1.1 ± 0.03 times broader than long (n = 10). Chelipeds smaller than male, the base-half dactylus dorsal margin with numerous granules. Pleon wide, rounded, telson semicircular, base partially inserted in somite 6. Vulva (Figs. 4J, 6L, M) not near anterior edge of sternite 5, operculum knob-like; posterior sternal vulvar cover rounded, not covering operculum. Colouration in life: There is considerable variation in colour, with the carapace brown to pale purple, usually with the gastric region dark brown; the chelae being reddish-orange to reddish-purple, with the tips of the fingers sometimes yellow (Figs. 1, 2). Ecology: This species can be found both on land (several meters away from water) and the muddy river bank in habitats typically about 250 m to 500 m away from sea. It has been found sympatrically with more Fig. 5. Bresedium brevipes (De Man, 1889). A–D, male (22.2 × 19.1 mm) (RMNH D1195), Batjan Island, Indonesia, right G1; E, F, male (21.3 × 18.5 mm) (ZRC), Taiwan, left G1; G, H, male (24.7 × 21.0 mm) (ZRC), Philippines, left G1. A, F, H, dorsal view; B, E, G, ventral view; C, D, distal part of G1. Scale bars = 1.0 mm. page 9 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan genetic data (Fig. 22). In life, adults of both species show similar colouration of carapace and legs, with large males of B. brevipes often possessing purple palms with finger tips yellow (Fig. 2B, F), with medium-sized and small males with light brownish red palms and orange fingers (Fig. 2C). Some specimens, however, have the entire chela purple (Fig. 2F). All specimens of B. eurypleon examined, however, always have purple palms and fingers, with the tip pale but not distinctly yellow (Fig. 7C, H). Sesarmops Serène and Soh, 1970 Type species: Sesarma impressa H. Milne Edwards, 1837, by original designation. Remarks: Serène and Soh (1970: 401) recognised five species in Sesarmops: S. atrorubens (Hess, 1865), S. impressus (H. Milne Edwards, 1837), S. intermedius (De Haan, 1835), S. mindanaoensis (Rathbun, 1914), and S. sinensis (H. Milne Edwards, 1853). Ng et al. (2008: 224) provisionally added Sesarma weberi (De Man, 1892) (from Flores) to Sesarmops. Sesarmops atrorubens is a poorly known species and was supposedly described from Sydney, Australia, by Hess (1865) and while it has also been reported from Timor, Ambon and Fiji (Tesch 1917: 131), its taxonomy is still unclear as it has never been described or figured to modern standards. Sesarmops mindanaoensis is also poorly known and was briefly described from one female from Mindanao, Philippines, and has never been figured. As for the type species, S. impressus (type locality not known), Sesarma similis Hess, 1865 (type locality supposedly Sydney, Australia), and Sesarma frontale A. Milne-Edwards, 1869 (type locality Madagascar), both the latter are currently regarded as junior synonyms (see De Man, 1887: 649; De Man, 1902: 527; Tesch, 1917: 158). We have examined the available types or material of S. atrorubens, S. impressus, S. similis and S. frontale, and the taxonomy of these species is complex and will have to be treated at another time. In summary, however, we have examined the dried type female of S. impressus in the Muséum National d’Histoire naturelle, Paris, France (MNHN). It is from an unknown location. Sesarmops frontale (A. Milne-Edwards, 1869) was described from Madagascar and we have also examined the type specimens in MNHN and they are identical to the type female of S. impressus. Specimens which have been called “S. impressus” from the West Pacific are superficially similar to S. impressus s. str. (presumably also from the Indian Ocean) and S. frontale, but differ in details of the carapace and G1 structures. Their colours in life are also strikingly different, with those from the Indian Ocean possessing cream to yellow carapaces and cream chelae whereas West Pacific material has dark purplish brown to brown carapaces with purple chelae (unpublished data). A preliminary genetic study shows the Indian and Pacific Ocean population represent two non-sister clades (Table 1; Fig. 22) and clearly belong to two species. Until their taxonomy can be properly resolved, they are here treated as one species for the moment, i.e., as Sesarmops impressus s. lato. The authors examined fresh specimens of Sesarmops atrorubens and it is a good species, very different from other Sesarmops species with a very short stout G1 and other characters that argue against its inclusion in in the genus (unpublished data). As suggested by Hess (1865) himself, S. similis is likely to be junior synonym of S. atrorubens as it was only known from a female from the same area the latter was collected. The systematics of S. atrorubens and related species will be dealt with at another occasion by the authors and CD Schubart. The present paper will only deal with two new species found in the Philippines and Taiwan; both are very distinct from S. atrorubens and S. impressus s. lato. Sesarmops mindanaoensis, however, is figured for the first time so that appropriate comparisons can be made with the new species. Sesarmops is clearly polyphyletic and some of the species (e.g., S. atrorubens as discussed earlier), certainly do not belong there. Its affinity to Bresedium, as noted earlier, is also in question. Ng et al. (2008: 224) have already commented that S. intermedius and S. sinensis (from China, Taiwan and Japan) did not belong to the same clade as S. impressus and was actually closer to some species of Chiromantes Gistel, 1848 and Pseudosesarma Serène and Soh, 1970; S. weberi was probably allied with Labuanium trapezoideum (H. Milne Edwards, 1837) instead. Of the two new species recognised here, S. mora n. sp. is closer to S. impressus s. lato in general features and, while clearly different species, are likely to be congeneric (Fig. 22). Sesarmops mindanaoensis, however, although possessing a generally similar carapace as the other species, has a different thoracic sternum and male pleon, and is unlikely to be a Sesarmops species as indicated by the genetic analysis (Fig. 22). Pending a revision of Sesarmops, however, it is retained here for the moment. Comparative material: Pseudosesarma edwardsii (De Man, 1887): 1 male (21.2 × 18.9), 1 female (16.9 × 15.4) (NCHUZOOL 16332), Langkawi, Peninsular Malaysia, coll. J.-J. Li, 19 December 2016 (see also Ng and Schubart 2017, for additional material). Pseudosesarma modestum (De Man, 1902): holotype male (25.0 × 20.9) (SMF 1989), Ternate, Moluccas, Indonesia, coll. W. Kükenthal, 26 December 1893–11 June 1894. Sesarmops impressus (H. Milne Edwards, page 16 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan 1837): 2 males (28.5 × 25.0, 23.4 × 27.6), 1 female (30.4 × 25.5) (ZRC 2009.0896), Mahi, Seychelles, coll. 2009; 1 male (37.6 × 32.1) (ZRC 2011.0005), station 9, Bassin Mro Oua Ouroveni, Mayotte, Comoros, coll. Tervuren Museum, 11 October 2000; 1 male (23.7 × 21.5) (ZRC 2015.0344), Bay of Bengal, South Andaman Islands, India, coll. I. Das, 20–30 August 1997; 1 female (36.7 × 34.8) (NCHUZOOL 15870), Gangkou R. estuary, Pingtung, Taiwan, 2 July 2001; 2 males (37.6 × 33.7, 35.4 × 32.3), 1 female (23.0 × 20.7) (NCHUZOOL 15069), lower reaches of Gangkou R. estuary, Pingtung, Taiwan, coll. J.-J. Li, 6 July 2017; 2 females (29.0 × 26.3, 28.9 × 26.8) (NCHUZOOL 15071), lower reaches of Gangkou R. estuary, Pingtung, Taiwan, coll. J.-J. Li, 18 May 2019; 1 male (35.2 × 34.6) (NCHUZOOL 15869), Lanyu, Taitung, Taiwan, 7 April 2002; 1 male (30.3 × 29.6) (NCHUZOOL 15868), Meilun R. estuary, Hualien, Taiwan, 29 July 2014; 2 males (larger 31.6 × 34.7) (ZRC 2017.0477), Guimaras I., Philippines, coll. J. C. E. Mendoza and L. Ganancial, 1 June 2017; 1 male (29.2 × 29.2) (NCHUZOOL 15871), Camiguin I., Philippines, coll. H.-T. Shih, 30 August 2003; 1 female (10.5 × 9.7) (ASIZ), Philippines, coll. H.-C. Liu, 15 February 2003. Sesarmops mindanaoensis (Rathbun, 1914) (Figs. 11A, B, 12–14) Sesarma (Sesarma) mindanaoense Rathbun, 1914: 75. Sesarmops mindanaoensis – Serène and Soh 1970: 401, 406; Ng et al. 2008: 223; Liu 2013: 32, fig. 2. Material examined: Holotype female (19.6 × 18.2) (USNM 45765), small stream south side of Cotabato, Mindanao, Philippines, coll. 20 May 1908. Philippines: Kawasan, Cebu: 1 male (34.1 × 31.6), 1 female (35.6 × 32.4) (ZRC 2014.0285), coll. H.-C. Liu, 3 December 2001; 5 males (30.8 × 29.9, 30.7 × 28.7, 31.6 × 29.1, 24.1 × 21.8, 23.5 × 21.6), 2 females (33.7 × 30.7, 29.0 × 26.7) (ZRC 2019.1658), coll. P. K. L. Ng, 30 July 2003; 1 male (36.4 × 35.0) (ZRC 2019.1657), 1 male (31.2 × 31.3) (NCHUZOOL 16333), 2 females (27.9 × 26.4, 26.0 × 24.9) (ZRC 2019.1657), coll. J.- J. Li, 6 September 2018; Loboc R., Bohol: 1 male (24.1 × 23.5), 3 females (18.6 × 17.5, 18.1 × 16.9) (ASIZ 72948), 1 male (22.5 × 21.7), 1 female (18.8 × 17.8) (ZRC 2019.1110), 1 female (16.4 × 15.4) (ASIZ 72948), Philippines: Loboc R., Bohol, coll. H.-C. Liu et al., 19 February 2003. Taiwan: 1 female (25.6 × 23.3) (NCHUZOOL 16334), 1 female (24.8 × 23.5) (NCHUZOOL 15858), Gangkou R. estuary, Pingtung, coll. J.-J. Li, 18 May 2017. Diagnosis of male: Carapace (Figs. 12A, E, 14A, B) nearly square in dorsal view, 1.0 ± 0.04 times broader than long (n = 4); regions well defined, separated by shallow grooves; postfrontal region distinct, separated into 4 lobes by deep grooves; front deflexed downwards, margin distinctly concave in dorsal view. Anterolateral margin with large triangular, exorbital angle and smaller, acutely triangular, epibranchial tooth; lateral margin straight, slightly divergent posteriorly. Cornea reaching edge of external orbital tooth. Chelipeds (Figs. 12F, G, 16C, D) robust, outer surface with numerous rounded granules, with a prominent line of tubercles along inner palm surface; dactylus curved, dorsal margin with numerous granules; proximal part of fixed-finger slightly concave, smooth. Ambulatory legs (Fig. 12A, E) slender; P3 and P4 subequal, longer than others, about 2.4 ± 0.1 times carapace width (n = 4). P3 merus 2.8 ± 0.1 times as long as broad (n = 4); upper margin with acute subdistal spine. Propodus of P3 3.0 ± 0.1 times as long as broad (n = 4), with accessory stria on inferior proximal portion of outer surface, dorsal and ventral margins with short stiff setae. Dactylus of P3 0.6 ± 0.1 times length of propodus (n = 4), slightly curved, terminating in acute calcareous tip; dorsal and ventral margins with short stiff setae. Pleon (Fig. 12B) relatively broad, all somites free. Telson semicircular, evenly rounded, as long as preceding somite, base of telson not inserted in somite 6. G1 (Figs. 16H, I, 17B, C) straight, relatively stout; apical process short, chitinous part short, ending in truncate tip; setae long, simple, originating at base of apical process. G2 shorter than quarter length of G1. Female: Carapace (Figs. 12C, 13A, B, 15A) more convex and broader than male, 1.1 ± 0.4 times broader than long (n = 6). Chelipeds (Figs. 13E, 14D, 15C) smaller than male. P3 merus slightly stouter than male, 2.7 ± 0.1 times as long as broad (n = 6). Pleon (Figs. 13H, 14G, 15B) wide, rounded, telson semicircular, base partially inserted in somite 6. Vulva (Figs. 16G, 17D) near anterior edge of sternite 5, central operculum tubular, oval shaped, directed anteriorly; posterior and anterior sternal vulvar covers low. Colouration in life: Carapace and legs dark or light brown, without prominent spots; male chelipeds purple or reddish purple, cornea greenish yellow (Figs. 11A, B, 12; Liu 2013). Preserved small specimens with some speckling on legs. Distribution: Taiwan (Pingtung) and Philippines (Cebu and Bohol). Ecology: Similar to Sesarmops impressus (H. Milne Edwards, 1837) in Taiwan and Philippines, but it has sometimes been found to climb large rocks and trees in the Philippines (J-J Li, personal observation). Remarks: Rathbun (1914: 75–76) described Sesarma (Sesarma) mindanaoensis from a relatively small but adult female specimen (19.6 × 18.2 mm) page 17 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan from a stream in Cotabato in Mindanao, Philippines. No figures were provided, but the author compared it to Pseudosesarma modestum (De Man, 1902) and Sesarmoides longipes (Krauss, 1843). On the basis of the description, Serène and Soh (1970: 401) transferred the species to their new genus, Sesarmops, without discussion. Liu (2013) mentioned there is a population of “Sesarmops mindanaoensis” in Kawasan, Cebu, Philippines, but did not elaborate on the matter. In the ZRC and/or ASIZ contain many specimens from the Philippines and Indonesia that were identified as Sesarmops mindanaoensis by the third author, Christoph Schubart and H-C Liu. This identification was based on comparisons with the holotype female almost 20 years ago, but none of the data have been published. The present study of the specimens, including new material from Taiwan as well as the type of S. mindanaoensis, confirms their conspecificity. Comparisons of similarly sized female specimens from the Philippines with the type of S. mindanaoensis show that they share many key characters, including the gentle convexity of the dorsal carapace surface (when viewed frontally); the shape of the external orbital angle (acutely triangular and directed obliquely outwards) (Figs. 13B, 14B); relatively more slender ambulatory meri and propodi where the dorsal and ventral margins of P4 and P5 are lined with dense short setae and scattered long setae (Figs. 13F, G, 14E, F); and the outer surface of the chela is smooth or almost so (Figs. 13E, 14D, 15C). The P2–P5 leg proportions may be slightly asymmetrical in some specimens. In the holotype female, the left P3 and P4 propodi are slightly longer (Fig. 13F) than those on the right P3 and P4 (Fig. 13G). There is one female specimen (21.5 × 19.7 mm, ZRC 2014.285) obtained from the Philippines which is similar in size to the holotype female and agrees with it in almost all aspects (Fig. 14), except that its left P2 and P3 propodi are slightly shorter (Fig. 14E) than those on the right instead (Fig. 14F). The ambulatory leg characters, however, do vary slightly. In another similarly sized female from the Philippines (18.8 × 17.8 mm, ZRC 2019.1110), the P4 dactylus and propodus appear proportionately longer and more slender, and the setae lining the margins of the P2–P5 propodus and dactylus are distinctly sparser (Fig. 15E, F) compared to the holotype female. Examining the series of specimens on hand, however, the differences in P3 and P4 meri and propodi, are not significant at the species-level as Fig. 11. Life colouration. A, B, Sesarmops mindanaoensis (Rathbun, 1914), male (specimen not collected), Philippines; C, S. mora n. sp., holotype male (27.7 × 25.5 mm) (NCHUZOOL 16137), Taiwan; D, S. mora n. sp., paratype female (25.2 × 22.6 mm) (NCHUZOOL 16335), Taiwan. page 18 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan they are too variable. That being said, none are ever as short and stout as those of S. impressus (Fig. 18E, F). The density of setae on the margins of the ambulatory propodus and dactylus varies in some specimens of S. mindanaoensis, sometimes appearing shorter and less dense; but it is always present (Figs. 13F, G, 14E, F, 15E–H). Comparing the holotype female of S . Fig. 12. Sesarmops mindanaoensis (Rathbun, 1914), colour in life. A, B, male (36.4 × 35.0 mm) (ZRC), Philippines; C, D, paratype female (24.8 × 23.5 mm) (NCHUZOOL 15858), Taiwan; E-G, male (30.8 × 29.9 mm) (ZRC 2019.1658), Philippines. A, C, E, overall dorsal view; B, D, ventral view of cephalothorax; F, frontal view of cephalothorax; G, outer view of left chela. page 19 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan Fig. 13. Sesarmops mindanaoensis (Rathbun, 1914), holotype female (19.6 × 18.2 mm) (USNM 45765), Philippines. A, overall dorsal view; B, dorsal view of carapace; C, frontal view of cephalothorax; D, left third maxilliped; E, outer view of left chela; F, left ambulatory legs; G, right ambulatory legs; H, pleon. page 20 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan mindanaoensis with similarly sized female S. impressus, the dorsal surface of the later species is more prominently inflated, the external orbital tooth is clearly directed anteriorly, the ambulatory meri and propodi are distinctly shorter and the outer surface of the chela is distinctly granulated (Fig. 18A–D). Fig. 14. Sesarmops mindanaoensis (Rathbun, 1914), female (21.5 × 19.7 mm) (ZRC 2014.285), Philippines. A, overall dorsal view; B, dorsal view of carapace; C, frontal view of cephalothorax; D, outer view of right chela; E, left ambulatory legs; F, right ambulatory legs; G, pleon. page 21 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan Fig. 15. A–F, Sesarmops mindanaoensis (Rathbun, 1914). A–F, female (18.8 × 17.8 mm) (ZRC 2019.1110), Philippines; G, H, male (22.5 × 21.7 mm) (ZRC 2019.1110), Philippines. D, right ambulatory legs; E, G, right P4 propodus and dactylus; F, H, right P5 propodus and dactylus. page 22 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan Sesarmops mora n. sp. (Figs. 11C, D, 19–21) urn:lsid:zoobank.org:act:93C54D7B-2847-4A82-A9A2D4A3CEC83A24 Sesarma frontalis – De Man 1892: 334, pl. 19(13). (not Sesarma frontale A. Milne-Edwards, 1869 = Sesarma impressa H. Milne Edwards, 1837). Material examined: Holotype: 1 male (27.7 × 25.5) (NCHUZOOL 16137), Gangkou R. estuary, Pingtung, Taiwan (21°59'17.3"N 120°50'01.6"E), coll. J.-J. Li, 18 May 2017. Paratypes: 2 females (28.0 × 25.8, 25.2 × 22.6) (NCHUZOOL 16335), same locality as holotype, coll. J.-J. Li, 18 May 2017; 1 female (25.8 × 23.5) (NCHUZOOL 16336), same locality as holotype, coll. J.-J. Li, 11 August 2017; 1 male (13.1 × 13.0) (NCHUZOOL 16337), same locality as holotype, coll. J.-J. Li, 25 September 2018; 1 male (26.0 × 24.2) (ZRC 2019.1111), same locality as holotype, coll. J.- J. Li, 10 June 2019. Others: Philippines: Kawasan, Fig. 16. Sesarmops mindanaoensis (Rathbun, 1914). A, C, D, I, H, male (36.4 × 35.0 mm) (ZRC), Philippines; B, E, F, G, female (24.8 × 23.5 mm) (NCHUZOOL 15858), Taiwan. A, B, frontal view of carapace; C, outer view of right chela; D, inner view of right chela; E, outer view of left chela; F, inner view of right chela; G, vulvae; H, I, left G1. page 23 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan Cebu: 2 males (27.5 × 24.1, 22.4 × 20.7) (ZRC 2019.1653), coll. H.-C. Liu, 2 December 2001; 5 males (33.3 × 30.4, 33.3 × 30.0, 27.7 × 25.6, 29.2 × 26.5, 22.2 × 20.4), 5 females (24.0 × 21.0, 19.6 × 17.1, 19.1 × 17.5, 16.0 × 14.2, 14.2 × 12.6) (ZRC 2019.1655), coll. P. K. L. Ng and C. D. Schubart, 3 December 2001; 2 males (25.0 × 23.1, 21.7 × 19.6) (ZRC 2019.1656), coll. N. K. Ng et al., 2 January 2002; 1 male (31.5 × 28.8), 1 female (27.2 × 24.8) (ASIZ 72950), coll. H.-C. Liu et al., 14 February 2003; 1 male (27.7 × 25.3), 1 female (25.3 × 23.9) (ZRC 2019.1654), coll. P. K. L. Ng et al., 30 July 2003; 1 male (27.3 × 25.1), 1 ovig. female (26.4 × 23.8) (ZRC 2012.0434), coll. P. K. L. Ng and P. Y. C. Ng, December 2010; 1 male (28.6 × 28.1) (NCHUZOOL 14910), coll. J.-J. Li, 6 September 2018. Indonesia: Manado Murex Resort, Sulawesi: 1 female (22.3 × 20.3) (ZRC 2019.1661), coll. P. K. L. Ng et al., 17 July 2003. Diagnosis of male: Carapace (Fig. 19A, E, F) nearly trapezoid in dorsal view, 1.1 ± 0.04 times broader than long (n = 4); regions well defined, separated by shallow grooves; postfrontal region distinct, separated into 4 lobes by deep grooves; front deflexed downwards, margin distinctly concave in dorsal view. Anterolateral margin with large triangular, exorbital angle and smaller, acutely triangular, epibranchial tooth; lateral margin straight, divergent posteriorly (Fig. 21A). Chelipeds (Figs. 19H, 20C, E) robust, outer surface with numerous rounded granules; dactylus curved, dorsal margin with numerous granules; proximal part of fixedfinger slightly concave, smooth. Ambulatory legs (Figs. 19A, E, F, 20G) slender; P3 and P4 subequal, longer Fig. 17. Sesarmops mindanaoensis (Rathbun, 1914), male (36.4 × 35.0 mm) (ZRC). A, carapace dorsal view; B, C, left G1; D, left vulvae. Scale bars = 1.0 mm. page 24 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan than others, about 2.3 ± 0.1 times carapace width (n = 4). P3 merus 2.6 ± 0.1 times as long as broad (n = 4); upper margin with acute subdistal spine. Propodus of P3 3.2 ± 0.1 times as long as broad (n = 4), with accessory stria on inferior proximal portion of outer surface, dorsal and ventral margins with short stiff setae. Dactylus of P3 0.8 ± 0.1 times length of propodus (n = 4), slightly curved, terminating in acute calcareous tip; dorsal and ventral margins with short stiff setae. Pleon (Fig. 19B) relatively broad, all somites free. Telson semicircular, Fig. 18. Sesarmops impressus (H. Milne Edwards, 1837), ovigerous female (26.0 × 24.0 mm) (ZRC 2001.307), Philippines. A, overall dorsal view; B, dorsal view of carapace; C, frontal view of cephalothorax; D, outer view of left chela; E, left ambulatory legs; F, right ambulatory legs. page 25 of 32Zoological Studies 59:16 (2020) © 2020 Academia Sinica, Taiwan Brachyura: Sesarmidae) from Taiwan and the Philippines from morphological and molecular evidence. Zool Stud 58:40. doi:10.6620/ZS.2019.58-40. Li YF, Du FY, Gu YG, Ning JJ, Wang LG. 2017. Changes of the macrobenthic faunal community with stand age of a non-native mangrove species in Futian Mangrove National Nature Reserve, Guangdong, China. Zool Stud 56:19. doi:10.6620/ZS.2017.5619. Liu HC. 2013. Cross Wallace’s Line. Taiwan Nat Sci 120:30–41. (in Chinese) Liu HC. 2016. Recreation area of Kenting National Park in 2015. (1) Ecological monitoring of land crabs, and land crab resource investigation of Siangjiaowan and Shadao areas. Kenting National Park, Pingtung, Taiwan, 93 pp. (in Chinese) Maenosono T, Naruse T. 2015. 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