taxonID	type	description	language	source
03BB623FFF8EC14DFE2F12B1AFBCFAC5.taxon	materials_examined	Type genus. Isolapotamon Bott, 1968 (by original designation). Diagnosis. Second gonopod elongated, terminal tube very narrow in cross-section, strongly sclerotized and stiOE; fused zone formed by a hook-like edge to which other edge perfectly adjusts; tubular cuticle with net-like structure, narrow, fused in nearly all parts with outer cuticle. Distribution. Borneo, Malaysia, West to Central Thailand, Eastern and Southern Burma, Hainan, South and South-East China, Taiwan, Philippines, Ryukyu Islands. Remarks. The family was established by Bott (1970 a) for species of the genus Isolapotamon from Borneo and the Philippines. Bott characterized the family exclusively by the terminal joint of the rst gonopod, which is longer than the subterminal joint or short and stout, distally often broader than basically. Bott included three genera Isolapotamon, Nanhaipotamon and Malayopotamon in this family. Later, the Isolapotamidae were synonymized with the Potamidae (Ng, 1986 b, 1988 a; Ng and Takeda, 1986; Ng and Yang, 1986; Ng and Tan, 1998) as distinct characters separating this family from the other Asian freshwater crabs were apparently lacking. This is de nitely correct if carapace and rst gonopod characters are taken into account. The present study shows clearly that the morphology of the second gonopod of Isolapotamon is very characteristic, and is similar to that of other genera from Thailand, Malaysia, South China and adjacent regions (gure 4). The morphology of the terminal tube of the second gonopod is constant within this group and distinctly diOEerent from that of the second gonopod of Potamon, the type genus of the Potamidae and from that of Sinopotamon, the type genus of the Sinopotamidae, as described above (gure 2). Morphologically, there is no transition between these morphotypes and every type is characteristic for a special geographic region. In contrast to this distinct characterization of groups, the status of the Potamidae, as currently de ned, is very unclear. The Potamidae are presently characterized according to the classi cation concept of Bott (1970 a, 1970 b). Bott characterized the Potamidae within the Potamoidea exclusively by the three-segmented mandibular palp. The presently used concept for the classi cation of the Potamidae basing on Bott’s concept is not useful due to several problems: The four-segmented gonopod was a morphological misunderstanding, as has been described above and thus has to be reconsidered as three-segmented. Concerning the carapace, there are many potamid species, which show a very similar shaping and sculpturation, but in several regions occur species Taxonomy and biogeography of the family Isolapotamidae 1299 which diOEer clearly from the others (e. g. Thaiphusa Ng and Naiyanetr, 1993; Thaipotamon Ng and Naiyanetr, 1993; Lobothelphusa Bouvier, 1917; Acanthopotamon Kemp, 1918). This means, within the Asian potamoid crabs, there are no carapace features which can be used consistently for the characterization of the entire family Potamidae. As stated by Cumberlidge (1999), the two-segmented mandibular palp is a distinct feature to characterize the Potamonautidae. As far as presently known, in all Asian potamoid freshwater crabs the mandibular palp is three-segmented. However, this is not an exclusive character of the Asian freshwater crabs, the same type of mandibular palp can also be observed in many marine crabs as in Carpiliidae Ortmann, 1893; Cancridae Latreille, 1803 or Mennippidae Ortmann, 1893 and might thus be a plesiomorphic state not useful as a de nition character of the Potamids. This means that the morphology of the copulatory apparatus, especially that of the second gonopod, remains the only consistent character set. Every morphotype of the second gonopod is characteristic for a number of Asian crab genera and is related to a special geographic region. Each of these types is characteristic for one of the type genera of the formerly described South-East Asian potamoid families. Thus, it is possible to distinguish the three families Potamidae, Sinopotamidae and Isolapotamidae on the basis of the second gonopod morphology thus diOEering from Bott’s circumscriptions. As concerns taxonomic ranking, in any case the Isolapotamidae and Sinopotamidae have to be treated at the same taxonomic level. This is the family rank in the presently accepted system. It might be that the status of these groups has to be changed to subfamily level. This can, however, only be done after the taxonomic and phylogenetic relations between Potamoidea, Gecarcinucoidea and the American freshwater crabs are analysed in detail. Until then a change in ranking does not solve any problems, but creates new confusion. In summary, the family Isolapotamidae can only be characterized consequently by a second gonopod with a very narrow tube and a characteristic contact zone. It is also obvious that this morphotype represents a special sperm transfer strategy. Morphological features supporting this theory are: the very stiOE cuticle of the terminal tube of the second gonopod; the fusion of the tube margin with the outer cuticle, rendering the walls of the tube massive and thus indicating a strong stabilization; the narrow tube lumen; the characteristic contact zone of the lateral margins closing the tube very tightly lengthwise. Malayopotamon is here excluded from the Isolapotamidae, because its second gonopod is morphologicall y very diOEerent from that of Isolapotamon as well as from those of Potamon and Sinopotamon. In spite of the morphological constancy of the second gonopod, the rst gonopod within the family Isolapotamidae is very variable especially in the shape of the terminal joint and the exible zone. Its morphology and shape is, therefore, not useful for taxonomic classi cation of higher ranks.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF8CC14BFE5B164DAF2CFDAB.taxon	materials_examined	Type species. [By original designation.] Potamon anomalus Chace, 1938. Diagnosis. Terminal joint of the rst gonopod longer or as long as subterminal joint, exible zone reduced to a small groove between terminal and subterminal joint. Opening of gonopodial tube ends in cone-like extension, distal tip additionally with hook- or thorn-like projection next to conical opening. Projection can be broadened, forming spoon-like structure in some species. Distribution. North Borneo, Mindanao. Taxonomy and biogeography of the family Isolapotamidae 1301 Remarks. Isolapotamon is easily characterized by the morphology of the rst gonopod. Especially characteristic are the elongation of the terminal joint, the distal positioning of the opening of the gonopod tube, and the hook-like extension next to it. The characteristic shape of the rst gonopod represents a speci c interaction mode with the female gonopore. In North Borneo (Mount Kinabalu) there is a high diversi cation of the genus in a comparatively small area (Ng and Tan, 1998). An important genus in this discussion is Minpotamon Dai and Türkay, 1997 from Fujian province, South China. The rst gonopod of Minpotamon closely resembles that of Isolapotamon, although Dai and Türkay (1997) did not discuss this similarity, their gures clearly show this. This similarity, however, indicates at least a close relation between Minpotamon and Isolapotamon as this characteristic morphology of the rst gonopod represents a speci c way of interaction with the female gonopore. The other possibility is that Minpotamon belongs to Isolapotamon and it would then be interpreted as a relict species that indicates a former wider distribution of the genus. In either case, this genus clearly belongs to the family Isolapotamidae. For a nal conclusion more material is necessary.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF8AC14BFE0811D3AFB9FA88.taxon	materials_examined	Material. One, one (juv.) (NMB 944 a) Bundutuan, Luidan river, Kina-Balu, North Borneo, 3000 feet, exch. Cambridge; one (SMF 2839) Luidan river, Kinabalu, North Borneo. Diagnosis. Distal part of terminal joint of rst gonopod with a dorsoventrally attened, broadened terminal projection that is distinctly separated from the cone-like gonopodial opening. Type locality. Bundutan, Luidan river, Mt Kinabalu, North Borneo. Distribution. North Borneo, in the Luidan river at the Mount Kinabalu. Measurements. 35.7: 26.9: 17.2: 8.8 (SMF 2839). Remarks. Isolapotamon anomalum is one of a number of species of this genus in the Kinabalu area, which were revised by Ng and Tan (1998). Within these species Isolapotamon anomalum most closely resembles I. griswoldi (Chace, 1938) based on the shape of the distal part of the rst gonopod. In both species the distal extension of gonopod 1 is distinctly separate from the gonopodial cone-like opening but this distal extension is rounded and more or less thorn-like in I. griswoldi while it is broad and dorsoventrally attened in I. anomalum.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF88C149FEF31193AFD2FA89.taxon	description	(gure 6 a – c)	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF88C149FEF31193AFD2FA89.taxon	materials_examined	Material. One, one (SMF 4507), Taiwan, Nantou, Chung-hsing Village, ded. J. K. Chia, ex coll. Tulane University collection; one (ZMB 12528), Taiwan, Kagi. Diagnosis. Terminal joint of rst gonopod dorsoventrally attened, broadly triangular in shape, formed by projection of mesial overlapping zone. Margins of mesial projection straight. Type locality. Taiwan. Distribution. Presently known only from Taiwan. Measurements. 34.2: 27: 18.8: 9.4 (ZMB 12528). Remarks. The species of Nanhaipotamon can be easily characterized by diOEerences in the shape of the rst male gonopod. The mesial projection of gonopod 1 has a typical triangular shape with straight margins, and Dai (1995) showed a large number of similar species with such triangular projections. However, according to the detailed drawings of Dai (1995), the species can be separated easily from each other by the shape of the margins of gonopod 1.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF88C155FE6C16F1AE8EFD03.taxon	materials_examined	Type species. Potamon (Potamon) manii Rathbun, 1904 [by original designation]. Diagnosis. Terminal joint of rst gonopod shorter than subterminal joint; S-shaped, overlapping margin reaching mesial side, margin of outer overlapping Taxonomy and biogeography of the family Isolapotamidae 1305 zone mesially projecting and sticking out, exible zone of rst gonopod present and elongated; distal part of subterminal joint neck-like, narrow; terminal part of second gonopod dorsoventrally attened; terminal tube extremely narrow, contact zone situated on mesial edge. Remarks. Demanietta belongs clearly to the Isolapotamida e based on the morphology of the second gonopod. The cross-section of the terminal tube of the second gonopod agrees fully with that of Isolapotamon because it shows the narrow tube lumen and the characteristic contact zone of the lateral edges, as well as the fusion of the tube margin with the outer cuticle. Demanietta can easily be characterized by the morphology of the rst gonopod, especially of the terminal joint and the structure of the exible zone and the neck-like distal elongation of the subterminal joint. Demanietta was originally established by Bott (1966) as a subgenus of Potamiscus Alcock, 1909. Bott (1970 b) later transferred Potamiscus (Demanietta) to the genus Ranguna Bott, 1966. Ranguna was regarded by other authors (Türkay and Naiyanetr, 1986; Holthuis, 1990; Ng, 1990) as a junior synonym of Potamiscus and the status of Demanietta became unclear. Naiyanetr (1992 a) recognized Demanietta at the genus level, and Ng and Naiyanetr (1993) rede ned the genus on the basis of carapace characters, assigning its species to two genera, Demanietta sensu Ng and Naiyanetr, 1993, with the type species D. manii, and Thaiphusa Ng and Naiyanetr, 1993 with the type species T. sirikit. According to Yeo et al. (1999) Demanietta and Thaiphusa can be distinguished by the following characters: the rst gonopod terminal segment fold of Demanietta is relatively higher than in Thaiphusa; the carapace is relatively at with well-de ned regions, versus an in ated, rounded carapace with poorly de ned regions; serrated and cristate anterolateral margins, versus low and rounded anterolateral margins; rugose and sharp epigastric cristae and postorbital cristae clearly separated from each other, versus rounded epigastric cristae and postorbital cristae almost con uent with each other; a broad to acutely triangular epibranchial tooth versus a low and rounded tooth; rugose and striated branchial and metabranchial regions versus regions smooth; a third maxilliped exopod agellum length subequal to, or greater than merus width, versus half to two-thirds as long as merus width. Further, Demanietta tend to be aquatic, while species of Thaiphusa tend to be more terrestrial. In my opinion the latter fact is the most important one. The described diOEerences in carapace and maxillipeds represent distinct ecological adaptations and are not necessarily indicators for taxonomical relations. Additionally, this kind of carapace structure occurs independently in diOEerent taxa, for example in the genus Thaipotamon, or in species of the family Gecarcinucidae. Thus, this carapace structure cannot be used as an exclusive taxonomic character for a special group. The excellent gures of Yeo et al. (1999) show that some species of Demanietta have high similarities with T. sirikit. The best example is D. kharikhan Yeo et al., 1999, which has a convex and smooth dorsal carapace, non-serrated lateral margins and low epibranchial teeth. This means that within the genus Demanietta several Taxonomy and biogeography of the family Isolapotamidae 1307 species show all transitions in the carapace structures between strongly sculptured species such as D. manii and non-sculptured species such as D. sirikit. Additionally, Brandis (2000) argued for Potamiscus Alcock, 1909, that the length of the third maxilliped agellum seems to be correlated with habitat. The more terrestrial the crabs are, the shorter the agellum. In this sense, these characters indicate diOEerent feeding modes and thus have to be considered as ecological adaptations, and can appear independently in non-related taxa and therefore are not meaningful for taxonomic classi cations of higher ranks. Finally, D. manii and Thaiphusa sirikit share the same general rst gonopod morphology representing a special interaction mode between male rst gonopod and female gonopore. According to the results for the genus Potamon (Brandis et al., 1999) the copulation mode in Demanietta is characterized by a projection of the terminal joint of the rst gonopod, formed by the outer overlapping margin and the neck-like elongated exible zone. The only variations of gonopod 1 between D. manii and T. sirikit are the height of the projection and the shape of the exible zone, but this can be easily explained as a speci c character. In other groups of freshwater crabs examined the shape of the terminal joint of gonopod 1 represents a generic character exclusively typical for a special group of freshwater crabs. Therefore, Thaiphusa is here regarded as a junior synonym of Demanietta.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF94C155FE24118BAE80FA2F.taxon	materials_examined	HOLOTYPE. One (MNHN 3602 - 82) Thailand, Bangkok, leg. Harmand. Diagnosis. Carapace appearing punctuated, slightly rounded; anterolateral margins well developed, cervical grooves deep, leading to lateral ends of postorbital margins. Postorbital margins sharp; without any separation, nearly connected with postfronta l lobes. Pleon elongately triangular, lateral margins straight. First gonopod elongated, terminal joint slightly curved outwards, ending in sharp tip, overlapping margin projecting, projecting margin rounded, reaching lateral margin of terminal joint proximally; exible zone distinctly elongated, slightly bilobed. Distribution. Presently known only from type locality. Type locality. Bangkok. Measurements. 48.2: 35.2: 20.6: 7.4 (holotype). Remarks. Recently many species closely related to D. manii have been described by Yeo et al. (1999), all showing a similar gonopod morphology. According to Yeo et al. (1999) D. manii is presently only known from Bangkok. As the authors mention it is very doubtful that this specimen really was collected in the vicinity of Bangkok. Due to the high similarity between D. manii and the new species described by Yeo et al. (1999) and the unclear type locality of D. manii the status of this species remains unclear and thus will not be discussed in the present paper.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF94C153FE261557AF04FA18.taxon	description	Taxonomy and biogeography of the family Isolapotamidae 1309	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF94C153FE261557AF04FA18.taxon	materials_examined	HOLOTYPE. (RMNHD 38758) Amphoe Sai Yok, Mountain creek in Ban Nam Chon: 14 ss 06 ¾ 00 ² N 99 ss 23 ¾ 00 ² E; leg S. Duangkhahae. PARATYPES. One, one: SMF 22111, Thailand, Kanchanaburi province, Sai Yok district, Mountain creek in Ban Nam Chon: 14 ss 06 ¾ 00 ² N 99 ss 23 ¾ 00 ² E; leg S. Duangkhahae. Diagnosis. Carapace smooth, anterolateral margin well developed, forming one sharp ridge with the postorbital and postfrontal lobes; lateral parts of ridge distinctly rounded, epibranchial teeth lacking; epigastrical groove half circled, chelae of male very unequal, cutting edges forming round, broad gap when closed. Pleon triangular. Terminal joint of rst gonopod slightly S-shaped, distal tip short; overlapping margin reaches dorsal side, only minutely projecting, margins appearing swollen; exible zone narrow, minutely bilobed. Type locality. Ban Nam Chon, Sai Yok District, Kanchanaburi Province, Thailand. Distribution. South Thailand. Measurements. 33: 47.7: 23.8: 11.3 (holotype). Remarks. The species can be characterized distinctly by the morphology of the rst gonopod as well as by carapace features. The mesial projection of the terminal joint is very low, while the carapace is convex and very smooth. According to Naiyanetr (1992 b) D. sirikit is a true land crab. As discussed above, most of the other known species of the genus Demanietta are aquatic and therefore, this species shows some diOEerences in carapace and maxilliped shape. Flabellamon Ng, 1996 (gures 4 b, 9 – 13) Flabellamon Ng, 1996: 1005. Type species. Flabellamon pretzmanni Ng, 1996 [by original designation]. Diagnosis. Terminal joint of rst gonopod with either mesially swollen or largely projecting outer overlapping margin. Terminal part of second gonopod dorsoventrally attened, fused zone of terminal tube of second gonopod turning one and a half times round axis of terminal tube; exible zone short; terminal tube ending in distinct minutely curved tip. Distribution. Both sides of the Tenasserim range, Kanchanaburi province, central Thailand. Remarks. The genus was established by Ng (1996) for F. pretzmanni and was originally monotypic. The examination of the second gonopod of material from the Natural History Museum Basel, cited by Ng as F. pretzmanni, shows a very characteristic second gonopod morphology with the contact zone of the tubular edges turning around the longitudinal axis of the second gonopod. Additionally, the terminal joint of the rst gonopod bears at least a small protrusion or swelling in all species examined, which in F. pretzmanni is enlarged to a broad projection. Comparison of Flabellamon with other species from Burma and western Thailand (such as Potamon turgidulimana Alcock, 1910; P. pruinosum Alcock, 1909; P. kanchanaburiens e Naiyanetr, 1992; or P. erewanense Naiyanetr, 1992) showed a general agreement of the second gonopod morphology between these species. It is possible that many more species belong to this genus than was previously thought. The cross-sections of the second gonopod of Flabellamon show agreement with that of Isolapotamon so this genus is included in the Isolapotamidae. The problematic status of the type species, F. pretzmanni, is described below.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF92C150FE111680ACFEFAE8.taxon	description	Taxonomy and biogeography of the family Isolapotamidae 1311 Type specimens. One, one: SMF 1761, Burma, leg. W. Theobald (exch. with the Indian Museum). Material. One, two: MLS 1343, valley of Houngdareau (5 Haungtharaw River, at the south-west slope of the Dawna Hills, Upper Tenasserim, South Burma: 16 ss 36 ¾ 00 ² N 98 ss 01 ¾ 00 ² E) 1887, leg. Fea; one: ZMB 8601, Meetan (5 Mitan Chaung (5 river) 15 ss 59 ¾ 00 ² N 98 ss 24 ¾ 00 ² E at the south-west slope of the Dawna mountain range), leg. Fea (Holotypus of Potamon kuehnelti); one, one: NMB 19 a, Meetan, leg. Fea; two: NMB 19 b, Kokareet, Tenasserim (5 Dawna Hills) leg. Fea. Diagnosis. Carapace smooth, lateral and frontal regions rugose; anterolateral margin well developed, serrated with equal-sized teeth, postorbital crests sharp, leading from distinct epibranchial teeth to postfrontal lobes, postfrontal lobes bulging, fused with gastric eld producing rhombi-like structure; chelae more or less equal, closing entire cutting edge; pleon slender, triangular, slightly concave. Terminal joint of rst gonopod with disk-like mesial bulging of overlapping zone, exible zone broad, with one median, elongated lobe. Type locality. Tenasserim, Burma. Distribution. West slope of Dawna hills. Remarks. Until now there has been a great deal of confusion concerning the distribution and taxonomy of this species, which is attributable to several facts: all available material is very old (19 th century to beginning of 20 th century), discrepancies in the descriptions published by Alcock (1909, 1910) and the unspeci c type locality (‘ Burma’). DiOEerent spellings of localities (e. g. Meetun – Meelan – Mitan) and unclear old records also contributed to this confusion. Alcock (1909) described the species on the base of 11 males and two females with the locality ‘ Burma’ collected by W. Theobald. These specimens are catalogued under the number 6952 / 3 in the Zoological Survey of India. Alcock described P. turgidulum as a small species similar to P. tumidum. According to Alcock (1909, 1910) the following features are characteristic for P. turgidulum: length of the carapace in adults being less than an inch; the indistinct and super cial carapacial grooves; the convex carapace; the narrow front with a bilobed edge; the second pair of legs being considerably longer than the chelipeds; epigastric crests separated from postorbital crests by an indistinct groove, forming ‘ the convexity of a common curve with them’. He gured one specimen in his revision of the Indian Potamidae (1910). Bott (1970 b) examined two specimens from the Senckenberg collections (SMF 1761) and from the Natural History Museum Basel (NMB 19 a, b) for his revision and assigned both to P. turgidulum. Ng (1996) pointed out that the specimen gured by Alcock (1910) and which he believed belonged to the type series diOEered from that of Bott (1970 b). He thus assigned specimens from the NRC (Singapore) that were similar to those of Bott to a new species, F. pretzmanni Ng, 1996. In fact, it seems that Alcock’s type series consisted of at least two species. This can already be seen from discrepancies in the original description of 1909 when compared with the gure published in 1910. The detailed description in the 1910 volume further supports this conclusion: Alcock (1910) described the epigastric crests as separated from the postorbital crests by an indistinct groove, forming ‘ the convexity of a common curve with them’. The gure of Alcock shows epigastric and postorbital crests which are distinctly concave and not all convex. I examined part of the type series, i. e. 2 (SMF 1761), which were examined by Bott (1970 b), 1 (NHM 1909.5.1.8.) and 1 (USNM 42774), all exchanged or presented by the Taxonomy and biogeography of the family Isolapotamidae 1313 Zoological Survey of India (ZSM 6952 / 3). This material con rms the heterogeneity of the type series, because SMF 1761 agrees with Alcock’s description cited above, while the two females look like his 1910 gure. This means that the name Potamon turgidulum, Alcock, 1909 could be either applied to the species described by Ng (1996) under the name F. pretzmanni, the identity of which does not pose any problems, or the gured specimen, of which the identity is totally unclear, even at the level of family assignment. It could be a Potamid, an Isolapotamid or a Sinopotamid. As I have no access to the male specimen gured by Alcock (1910) and as the two female syntypes (NHM 1909.5.1.8. and USNM 42774) do not help in the solution of this problem the identity of this form remains dubious. I, therefore, prefer to use Alcock’s P. turgidulum in the sense of F. pretzmanni, which has the consequence of the synonymy of both. By this action it can be avoided that a dubious name would oat around and form a potential threat for any name of species of this area. When the male specimen in the Zoological Survey of India becomes available, it can then either be identi ed with another described species, or be given a new name. In any case this is in my opinion the best solution for the stability of nomenclature. One small specimen from the Kokareet / Dawna mountains (NMB 19 b) shows a mesial disc-like projection of the rst gonopod terminal joint, which is narrower than that of the larger male specimen of the same sample and that of the specimens from Mitan (NMB 19 a) and the Haungtharaw river (MLS 1343). This narrowing of the projection of the single small specimen from the Dawna mountains (NMB 19 b) already mentioned by Bott (1970 b) and Ng (1996) is not enough of a diOEerence to establish a distinct species, mainly because the other specimen from the same sample shows the same large disc-like projection as all other examined specimens of this species. Most probably, the smaller specimen is subadult and the structural diOEerence of the rst gonopod is caused by growth and maturation eOEects. Additionally, larger series from the Dawna hills are lacking and a more detailed study of the morphologic variation of the rst gonopod is presently not possible. Thus, this diOEerence should not be used at present to split oOE another species until more abundant material from this region becomes available. Finally, the comparison of the rst gonopods of F. turgidula and P. kuehnelti shows that both are morphologically completely identical. Therefore, based on available material, F. turgidula is the only valid species, while P. kuehnelti and F. pretzmanni are here treated as junior synonyms of F. turgidula. The zoogeography of this species is interesting. It is so far known only from the western and southern slopes of the Dawna hills, which means that it could be endemic in this region.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF91C15FFEFF161FAE74FCCA.taxon	materials_examined	Type material. Burma: one, one: USNM 42773, upper Tenasserim, don. Indian Museum; one: NHM 1909.9.2.2., upper Tenasserim, Indian Museum. Diagnosis. Carapace smooth, anterolateral margin indistinct, formed only by very small regular teeth, gastric groove deep, connected with indistinct sinuous cervical groove, postorbital crest distinct, not sharp, sinuous, beginning at very small epibranchial tooth leading straight to postfrontal lobes. Chelipeds slightly unequal, chelae rugose, short, cutting edges with large teeth, pleon slender, triangular. Terminal joint of rst gonopod conical, lateral margin rounded, overlapping zone reaches mesial dorsolateral edge. Terminal joint with a mesial conical protuberance on outer overlapping margin; exible zone strongly elongated with one lobe on lateral side. Type locality. Upper Tenasserim. Distribution. Upper Tenasserim. Measurements. 23.7: 18.9: 8.4: 6.8 (NHM 1909.9.2. 2). Remarks. The taxonomic status of this small species has not been discussed since Bott (1970 b). The species was described by Alcock (1910) as Potamon (Potamon) turgidulimana, who distinguished the species by the absence of a gap between the external orbital tooth and the lower border of the orbit, and by the degree of expansion of the palm of the larger cheliped. Bott (1970 b) used mainly rst gonopod characters and determined this taxon to be Ranguna (Ranguna) turgidulimana, due to the mesial projection of the rst gonopod terminal joint. Re-examination of the available type specimens here showed that the species can be easily determined by the morphology of the rst gonopod, and that the second gonopod morphology agrees with that of F. turgidula. Both gonopods are dorsoventrally attened and the fused zone of the terminal tube of the second gonopod turns one and a half times round the axis of the terminal tube.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF9EC15CFE1D1033A92AFF8D.taxon	materials_examined	Type material. Burma: one (NHM: 1909.9.2.1), Tavoy: 14 ss 05 ¾ 00 ² N 98 ss 12 ¾ 00 ² E, exch. Indian Museum. Diagnosis. Carapace smooth, anterolateral margin well developed, serrated with small, but distinct teeth, postorbital crests very sharp, connected with epibranchial teeth as well as with postfrontal lobes, frontal region nearly rectangular in shape; chelipeds equal, cutting edges of the ngers of the chelipeds not gaping when closed. Pleon triangular in shape, lateral margins slightly convex. Terminal joint of the rst gonopod conical, dorso-mesial part of terminal joint bulging in basal region. Flexible zone of the rst gonopod bilobed, mesial lobe distinctly elongated, divided into two parts. Subterminal joint slightly S-shaped, lateral margins bear numerous setae. Type locality. Tavoy, Tenasserim, Burma. Distribution. Western Thailand, southern Burma. Measurements. 31.3: 40.5: 17.8: 13 (male RMNH D 41619). Remarks. Examination of the second gonopod of a type specimen of P. pruinosum shows clearly that this species belongs to the genus Flabellamon, because the fused zone of the terminal joint turns one and a half times round the axis of the terminal Taxonomy and biogeography of the family Isolapotamidae 1315 tube. This species closely resembles F. kanchanaburiens e (see below). Both taxa show a similar morphology of the rst gonopod, especially the characteristic terminal joint, which in both species bears a similar mesial protrusion and the overlapping zone turns to the dorsal side at the base of the distal tip. The main diOEerence is the shape of the exible zone, while in F. pruinosum the exible zone is distinctly bilobed, it is strongly elongated and not bilobed in F. kanchanaburiense. Taxonomy and biogeography of the family Isolapotamidae 1317	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF9AC15BFED613F5ACDFFB32.taxon	materials_examined	HOLOTYPE. (RMNH D 42352) Sai Sok Waterfall, Amphoe Sai Yok, Changwat Kanchanaburi, 7 March 1976, leg. P. Naiyanetr. PARATYPES. One, one (RMNH D 41616) Sai Sok Waterfall, Amphoe Sai Yok, Changwat Kanchanaburi, 19 July 1981, leg. P. Naiyanetr. Material. One, one (SMF 24742): Sai Sok Waterfall, Amphoe Sai Yok, Changwat Kanchanaburi: 14 ss 06 ¾ 00 ² N 99 ss 23 ¾ 00 ² E, 14 April 1974, leg. Warin. Diagnosis. Carapace smooth, anterolateral margin well developed, serrated with distinct regular teeth, cervical groove deep in the basal part, Postorbital margin distinct, sharp, sinuous, reaching triangular epibranchial tooth and ending below postfrontal lobes; chelipeds distinctly unequal, only large cheliped with ngers slightly gaping when closed, lined with diOEering teeth on cutting edges, surface of chelae rugose, pleon slender triangular. Terminal joint of rst gonopod cylindrical, slender; lateral margin straight, overlapping zone reaching the dorso-mesial edge. Overlapping zone forming a conical protuberance on outer overlapping margin at half of terminal joint; exible zone strongly elongated, asymmetric with one mesial lobe; subterminal joint elongated, straight, outer margin sinuous, with a dorso-latera l deep groove close to exible zone. Type locality. Sai Sok Noi Waterfall, Sai Yok district, Kanchanaburi province. Distribution. Presently known only from the type locality. Measurements. 47.7: 62.4: 15.4: 8.6 (holotype). Remarks. The species is well characterized by its rst gonopod morphology which shows no variation within the material examined. Distinct characters of the rst gonopod are the overlapping zone which forms a conical protuberance on the outer overlapping margin and the exible zone, which is strongly elongated and asymmetric, with one mesial lobe. Re-examination of the holotype and the paratypes here shows clearly that the morphology of the second gonopod is congruent to that of Flabellamon turgidula. The fused zone of the terminal tube of the second gonopod turning one and a half times round the axis of the terminal tube, as well as the cross-section of the terminal tube is characteristic. Therefore this species is transferre d to the genus Flabellamon.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF9AC159FEF51662AE38FD8B.taxon	description	PARATYPES. One, one: (RMNH D 41619) Kanchanaburi province, Erewan waterfall, Thailand, 25 December 1990, leg Naiyanetr. Diagnosis. Carapace appears stippled due to numerous stumps of setae, anterolateral margin distinct, serrated with small regular teeth, gastric groove deep, connected with indistinct sinuous cervical groove, postorbital crest sharp, straight, connected with a small epibranchial tooth leading to postfrontal lobes, which are on the same level. Chelipeds slightly unequal, chelae rugose, short, cutting edges of ngers with large teeth. Pleon slender, triangular. Taxonomy and biogeography of the family Isolapotamidae 1319 Terminal joint of rst gonopod conical, lateral margin straight, overlapping zone facing ventral side. A conical protuberance occurs mesially on outer overlapping margin of terminal joint; exible zone bilobed. Type locality. Erewan waterfall, Kanchanaburi province. Distribution. Presently known only from type locality. Measurements. 30.6: 40.1: 12.3: 15.1 (RMNH D 41619). Remarks. F. erewanense can be easily characterized by the shape of the rst gonopod terminal joint, which diOEers from all other species included in Flabellamon, because the overlapping zone is in the ventral position. In common with the other species, F. erewanense bears a small mesial protuberance on the outer overlapping margin. Flabellamon erewanense was originally described (Naiyanetr, 1992 b) as a species of Potamon, bearing a distinct and well-developed agellum on the exopod of the third maxilliped (Naiyanetr, 1992 b). Examination of the second gonopod of the paratype shows clearly that this species shows the characteristic torsion of the terminal tube and is here reassigned to the genus Flabellamon.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF99C166FEF3157BAE8AFD48.taxon	description	(gure 16 a – c)	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFF99C166FEF3157BAE8AFD48.taxon	description	PARATYPES. One, one (RMNH 41617) Thailand, Tak province, Amphoe Mae Sot, Pa Charoen waterfall, 13 October 1989, leg. P. Naiyanetr. Diagnosis. Terminal joint of rst gonopod cylindrical, distally ending in a sharp spine, overlapping margin forming mesial projection. Terminal joint distally ending in narrow spine. Flexible zone asymmetric, bilobed; lateral lobe more elongated. Type locality. Pa Dang, Mae Sot District, Tak province, Thailand. Distribution. Presently known only from Tak province, Thailand. Remarks. The species was rst mentioned by Naiyanetr (1978) as a nomen nudum but later clari ed (Ng, 1992 b). Ng and Naiyanetr (1993) described close a nities between P. maesotense and P. boonyaratae (Naiyanetr, 1987) based on carapace features, the agellum of the exopod of the third maxilliped and similar ambulatory legs. The present investigation of the copulatory apparatus shows both species to diOEer in the basic morphology of the second gonopod. Takpotamon maesotense has a second gonopod which is characteristic for Isolapotamidae, while P. boonyaratae shows a nities to Thaipotamon. The rst gonopod of T. maesotense is characterized by a mesial projection as well as by the long distal spine of the terminus of the terminal joints ends.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFFA2C163FECD13F5AC40FC7E.taxon	materials_examined	Material. One, one (USNM 29993) Ile Poulo-Condore (5 Con Son), Vietnam: 8 ss 41 ¾ 00 ² N 106 ss 37 ¾ 00 ² E, leg. M. Harmand; one (NMB 908 a) Poulo Condore, November 1933, don. Mus. Singapore. Diagnosis. Carapace smooth, slightly grooved, lateral regions granulated, anterolateral margin well developed, serrated with equal teeth, postorbital margins and postfrontal lobes fused to sharp margin, which leads nearly to lateral edge, chelipeds unequal, ngers of both chelae slightly gaping, palms rugose, walking legs distinctly elongated; pleon stoutly triangular, terminal joint of rst gonopod long, slender cylindrical, slightly curved outwards, overlapping zone reaching only ventral part, in middle with a small mesial bulging at overlapping margin. Type locality. Ile Poulo-Condore (5 Con Son), Vietnam. Distribution. Presently known only from the type locality. Remarks. This species is the type of Dromotelphusa Nayianetr, 1992. The second gonopod morphology of D. longipes is unique and it is another exclusive character for this genus.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFFA2C161FE1310AEAD9BFE0C.taxon	description	(gure 19 a – c) Potamon (Potamiscus) chaseni Roux, 1934: gure 1, pl. 4, gures 1, 2; Roux, 1936: 37, gures 7, 8.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
03BB623FFFA2C161FE1310AEAD9BFE0C.taxon	materials_examined	Material. Malaysia: 2, 1: SMF 2836, Malayan peninsular, Cameron Highlands: 4 ss 29 ¾ 00 ² N 101 ss 23 ¾ 00 ² E. Diagnosis. Carapace smooth, deeply grooved, lateral regions granulated, anterolateral margin well developed, serrated with equal teeth, postorbital margin and postorbital lobe fused to sharp margin, which leads nearly to the lateral edge; chelipeds unequal, both slightly gaping, palms rugose, pleon stoutly triangular. Terminal joint of rst gonopod long, slender cylindrical, slightly curved outwards, overlapping zone reaching only ventral part, in middle with small mesial bulging at the overlapping margin. Type locality. Malayan peninsula, Cameron Highlands. Distribution. Malayan peninsula, Cameron Highlands. Measurements. 24.8: 32: 13.8: 9.7 (holotype NMB 882 a). Remarks. D. chaseni from the Cameron highlands of Malaysia was originally assigned by Roux (1934) to Potamon (Potamiscus) Alcock, 1909. Bott (1970 b) Taxonomy and biogeography of the family Isolapotamidae 1327 transferred it to Isolapotamon but the reason for this remains unclear. Bott (1968) established Isolapotamon for a group of species, with a rst gonopod with a terminal joint longer, or as long as the subterminal joint. Dromotelphusa chaseni distinctly has a rst gonopod with the terminal joint much shorter than the subterminal joint, and Ng (1988 a) transferred it to Stoliczia, Bott, 1966, based on carapace characters, and its highland type locality. Re-examination of the holotype of D. chaseni clearly showed that the second gonopod has the characteristic features of Isolapotamidae and that the rst gonopod agreed with that of D. longipes. On the other hand, the type species of Stoliczka stoliczkana shows the typical potamid-like second gonopod with a large tube lumen and two attached and incurved lateral margins as shown in gure 2 a.	en	Brandis, Dirk (2002): On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura). Journal of Natural History 36 (11): 1291-1339, DOI: 10.1080/00222930110051743, URL: http://www.tandfonline.com/doi/abs/10.1080/00222930110051743
