taxonID	type	description	language	source
03A88E3DC202443B546DFC48FE2B7D21.taxon	type_taxon	Type species. Erimetopus spinosus Rathbun, 1894.	en	Cumberlidge, Neil, Reed, Sadie K. (2004): Erimetopus vandenbrandeni (Balss, 1936) n. comb., with notes on the taxonomy of the genus Erimetopus Rathbun, 1894 (Brachyura: Potamoidea: Potamonautidae) from Central Africa. Zootaxa 422 (1): 1-27, DOI: 10.11646/zootaxa.422.1.1, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.422.1.1
03A88E3DC202443B546DFC48FE2B7D21.taxon	diagnosis	Diagnosis. Carapace outline subhexagonal / rounded; epibranchial tooth large, sharp, pointing forward, positioned well behind postfrontal crest; mandibular palp two­segmented, terminal segment simple; orbit narrow (1 / 7 cw), upper orbital margin semi­circular; anterolateral margin between exorbital and epibranchial teeth very long, curving slightly outward, with several small pointed teeth, lacking identifiable intermediate tooth; exopod of third maxilliped with long flagellum, ischium smooth lacking vertical sulcus; first carpal tooth on inner margin of carpus of cheliped large, slender, pointed, curving forward; series of pointed teeth on outer margin of carpus of P 1; superior margins of meri of P 2 – P 5 with two large, pointed distal teeth; carpi of P 2 – P 4 with spines on anterior margins, posterior margins smooth; propodi of P 2 – P 4 with spines on anterior margins, posterior margins smooth; propodus of P 5 with spines on anterior and posterior margins.	en	Cumberlidge, Neil, Reed, Sadie K. (2004): Erimetopus vandenbrandeni (Balss, 1936) n. comb., with notes on the taxonomy of the genus Erimetopus Rathbun, 1894 (Brachyura: Potamoidea: Potamonautidae) from Central Africa. Zootaxa 422 (1): 1-27, DOI: 10.11646/zootaxa.422.1.1, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.422.1.1
03A88E3DC202443B546DFC48FE2B7D21.taxon	discussion	Discussion. The absence of gonopod characters for some of the taxa included in this study is unfortunate, but it does not in itself discount the validity of utilizing other morphological characters to characterize the genus and to distinguish between its species. For example, our assignment of Erimetopus to the Potamonautidae is based on characters of the mandibular palp (2 ­ segmented) (Bott 1955; Cumberlidge 1999), and of the second antennal segment (broad enough to fill the lateral margin of the antennular fossa). These characters are shared with the other genera of potamonautid freshwater crabs, including Potamonautes. Additional family­level characters found in Erimetopus (which have still to be confirmed for E. brazzae) include a first gonopod that is in 4 parts, with a terminal article that is about one­third as long as the subterminal segment (Figs. 31 – 33, 42 – 44), and a second gonopod with a flagellum­like terminal article (Figs. 34 – 35). Fortunately, even without gonopod evidence, Erimetopus is clearly distinct in many respects from other potamonautid genera in Africa. Characters that unequivocally characterize this genus when considered in combination include a carapace outline that is subhexagonal / rounded; a series of pointed teeth on the outer margin of the carpus of the cheliped; two large, pointed distal teeth on the superior margins of the meri of pereopods P 2 – P 5; spines on the anterior margins of the carpi of pereopods P 2 – P 4; spines on the anterior margins of the propodi of pereopods P 2 – P 4; and spines on the anterior and posterior margins of the propodus of P 5. Similarly, other characters of the carapace, eyes, and pereopods easily distinguish between the two species of Erimetopus. The absence of gonopod evidence in this case presents a challenge to taxonomists who are continually seeking new characters (whether gonopod or not) to distinguish between taxa. In this regard, it should be remembered that gonopod characters (although informative) restrict the use of identification keys to males, whereas diagnostic characters of the carapace, eyes, anterior sternum, and pereopods offer the advantage that they permit the identification of all specimens, including females and juveniles. The lack of gonopod evidence for E. brazzae prompted Bott (1955) to admit to uncertainty about the proper taxonomic placement of Erimetopus. Despite this uncertainty, that author took the radical taxonomic step of assigning Erimetopus to the genus Potamonautes. Bott (1955) assigned E. brazzae to the genus Potamonautes because both taxa share a 2 ­ segmented mandibular palp, and because both lack an intermediate tooth on the anterolateral margin of the carapace between the exorbital and epibranchial teeth. However, neither of these characters is exclusive to Potamonautes or to Erimetopus. For example, a 2 ­ segmented mandibular palp is shared by all African potamonautid genera, and an intermediate tooth is also lacking in Potamonemus (Cumberlidge 1999). Unfortunately, the characters used by Bott (1955) to distinguish E. brazzae from his subgenera of Potamonautes (such as differences in the cornea length and carapace anterolateral margin tooth patterns) are not shared by all species of Erimetopus, and are therefore interpreted here as characters suitable for species separation within the genus Erimetopus. In the present work, characters that are shared by both species of Erimetopus, and which distinguish this genus from Potamonautes include a subhexagonal carapace outline, the presence of a row of small teeth on the anterolateral margin between the exorbital and epibranchial teeth, 2 or 3 teeth on the outer margin of the carpus of the cheliped, and spines on the margins of the carpi and propodi of pereopods P 2 – P 5. In the present study we have made a cautious use of the newly available gonopod characters of E. vandenbrandeni, because of the absence of male specimens of E. brazzae, E. spinosus and P. (E.) b. frontospinulosa. As a general rule, certain gonopod characters tend to be invariant at different taxonomic levels. For example, a four­part first gonopod (consisting of three segments plus a well­developed terminal article) is typical of that found in all families of Old World freshwater crabs (Bott 1970; Ng 1988; Cumberlidge 1999). Gonopod characters that tend to be invariant among congeners include the overall length and shape of the subterminal segments and terminal articles of gonopods 1 and 2. We consider it likely that these characters in E. vandenbrandeni will likely prove to be similar to those of E. brazzae (Bott 1955; Cumberlidge 1999) when the appropriate specimens become available. Relationships. A number of characters seen in Erimetopus are also found in species of platythelphusid African freshwater crabs such as Platythelphusa armata (A. Milne­ Edwards, 1887) from Lake Tanganyika in East Africa (Cumberlidge et al. 1999). These characters include a subhexagonal carapace outline, a row of small teeth on the anterolateral margin of the carapace between the exorbital and epibranchial teeth, a cheliped whose carpus has 2 or 3 teeth on the outer margin, and a front whose anterior margin projects straight out or is only slightly deflexed. However, Erimetopus can be easily distinguished from Platythelphusa as follows. The number of segments of the mandibular palp is normally used as a family­level character for the freshwater crabs (Bott 1970; Ng 1988; Cumberlidge 1999). In this case, the mandibular palp of Platythelphusa is 3 ­ segmented, whereas that of Erimetopus is 2 ­ segmented. In addition, the following characters in Platythelphusa are different from those in Erimetopus: the external angles of the front are either marked by sharp spines or by small granules, there is a stout triangular process (which may be produced into a small tooth) beneath the external angles of the front that descends into the orbital hiatus, and the medial end of the suborbital margin is marked by a distinct spine or small tooth (Cumberlidge et al. 1999). In addition, the first gonopod of Platythelphusa tapers to a pointed tip, whereas that of Erimetopus is tubular (although this character has yet to be confirmed for E. brazzae). Several workers (A. Milne­Edwards 1886; Balss 1936; Bott 1970; Rodriguez 1982, 1986; Ng & Rodriguez 1995) have commented on similarities (such as the subhexagonal / rounded carapace outline and the bilobed frontal margin) between E. brazzae and species of South American river crabs of the family Trichodactylidae (such as Trichodactylus and Dilocarcinus). However, we consider that such similarities are insufficient to argue for a relationship between Erimetopus and the trichodactylids. Moreover, there are a number of major differences in the diagnostic characters of Erimetopus and members of the Trichodactylidae (Rodriguez 1992; Magalhães & Türkay 1996 a, b, c) which strongly discount a close relationship between these taxa. For example, the mandibular palp of Erimetopus is 2 ­ segmented, while that of the trichodactylids is 3 ­ segmented; the merus of the third maxilliped of Erimetopus is broadly rectangular, while that of the trichodactylids is slim and triangular; and the dactyli of P 2 – P 5 of Erimetopus have rows of stiff corneous spines, while those of the trichodactylids lack spines and are fringed with hair­like setae. In addition, gonopod 1 of Erimetopus is 3 ­ segmented with a distinct terminal article, while that of the trichodactylids is 3 ­ segmented, and lacks the terminal article. These conclusions are supported by a number of substantial studies that indicate that the trichodactylids belong to a lineage that is independent of any of the other freshwater crab families (including the African Potamonautidae), and that the Trichodactylidae properly belongs in, or close to, the marine superfamily Portunoidea (Rodriguez 1992; Magalhães & Türkay 1996 a, b, c; Sternberg 1997, 1998; Sternberg et al. 1999; Sternberg & Cumberlidge 2001, 2003; Martin & Davis 2001).	en	Cumberlidge, Neil, Reed, Sadie K. (2004): Erimetopus vandenbrandeni (Balss, 1936) n. comb., with notes on the taxonomy of the genus Erimetopus Rathbun, 1894 (Brachyura: Potamoidea: Potamonautidae) from Central Africa. Zootaxa 422 (1): 1-27, DOI: 10.11646/zootaxa.422.1.1, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.422.1.1
03A88E3DC20D4429546DFA30FB977BA1.taxon	materials_examined	Type material: Democratic Republic of Congo (formerly Zaire): Lectotype (here designated), male subadult (cw 16.8, cl 12.4, ch 4, fw 4.4 mm) Kinshasa, 04 ° 17 ’ 60 ” S, 15 ° 18 ’ E, coll. G. F. de Witte, 31. viii. 1930 (MRAC 1273). Paratypes, 2 females, both ovigerous (cws 30.4, 28.5 mm) Kinshasa S 04 ° 19 ’, E 015 ° 19 ’, 1926, coll. Dr. van den Branden (MRAC 247 ­ 248). Paratype, female, ovigerous (cw 35.5 mm) coll. Dr. van den Branden, 1926 (MRAC 251); paratype, female, ovigerous (cw 29.8 mm), Kinshasa, coll. Dr. van den Branden, 1926 (MRAC 252); paratype, female, ovigerous, Kinshasa, 1931, coll. C. Henrard (MRAC 1640). Additional material. Democratic Republic of Congo: female, ovigerous (cw 30 mm) Kinshasa, coll. Dr. van den Branden, 1926 (MRAC 249); female, ovigerous (cw 33.8 mm), Kinshasa, coll. Dr. van den Branden, 1926 (MRAC 250); female, ovigerous (cw 35.1 mm), Kinshasa, coll. Dr. van den Branden, 1926 (MRAC 253); female, ovigerous (cw 38 mm), Kinshasa, coll. Dr. van den Branden, 1925 (MRAC 1557); female, ovigerous (cw 35.2 mm), Kinshasa, coll. Dr. van den Branden, 1925 (MRAC 1559); 3 females, all ovigerous (cws 24.9, 22.7 mm, one damaged), Kinshasa, coll. Dr. van den Branden, 1930 (MRAC 1566 – 1568); 2 females, both ovigerous (cws 24, 22.6 mm), Kinshasa, coll. C. Henrard, 1931 (MRAC 1634 – 1635); 4 females, all ovigerous (cws 31.2, 25.8, 25.8, 22.6 mm), Kinshasa, coll. C. Henrard, 1931 (MRAC 1636 – 1639).	en	Cumberlidge, Neil, Reed, Sadie K. (2004): Erimetopus vandenbrandeni (Balss, 1936) n. comb., with notes on the taxonomy of the genus Erimetopus Rathbun, 1894 (Brachyura: Potamoidea: Potamonautidae) from Central Africa. Zootaxa 422 (1): 1-27, DOI: 10.11646/zootaxa.422.1.1, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.422.1.1
03A88E3DC20D4429546DFA30FB977BA1.taxon	diagnosis	Diagnosis. Frontal margin smooth; either straight or only faintly indented in center; eyestalk normal length, not tapering distally; cornea not reduced, pigment dorsal and ventral; margin of meri of P 2 – P 5 lined by dense hair­like setae; second carpal tooth of P 1 reduced (much smaller than first carpal tooth); carapace very flat (ch / fw 0.9); carapace height less than front width; anterolateral margin between exorbital, epibranchial teeth very long, straight, directed outward then curving sharply inward, forming deep sinus before meeting epibranchial tooth; terminal article of gonopod 1 one­third as long as subterminal segment, terminal article tubular with parallel sides, medial and lateral folds low and even throughout length, tip of terminal article broad, with distinct triangular medial corner; distal margin of subterminal segment of gonopod 1 distinctly indented in middle; dorsal membrane broadest in middle, tapering sharply at both sides, narrowest at lateral and medial margins; gonopod 2 long, terminal article long, slender, flagellum­like.	en	Cumberlidge, Neil, Reed, Sadie K. (2004): Erimetopus vandenbrandeni (Balss, 1936) n. comb., with notes on the taxonomy of the genus Erimetopus Rathbun, 1894 (Brachyura: Potamoidea: Potamonautidae) from Central Africa. Zootaxa 422 (1): 1-27, DOI: 10.11646/zootaxa.422.1.1, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.422.1.1
03A88E3DC20D4429546DFA30FB977BA1.taxon	description	Redescription. Carapace outline subhexagonal / rounded. Frontal margin smooth, either straight or faintly indented in center; front horizontal or only slighlty deflexed; front narrow (fw / cw 0.3); postfrontal crest incomplete, epigastric lobes continuous with postorbital crests, but lateral ends of postorbital crests not meeting anterolateral margins. Exorbital tooth small, pointed; epibranchial tooth large, sharp, directed forward, positioned well behind postfrontal crest. Eyestalks normal length, not tapering distally; cornea not reduced, pigment dorsal and ventral; orbit narrow (1 / 7 cw), upper orbital margin semi­circular; carapace flat, height less than front width (ch / fw 0.9). Anterolateral margin of carapace between exorbital and epibranchial teeth lacking intermediate tooth; margin granulated, very long, straight, directed outward, then curving sharply backward, forming deep sinus before meeting epibranchial tooth; anterolateral margin of carapace posterior to epibranchial tooth with two small teeth behind epibranchial tooth; margin continuous with posterolateral margin. Carapace sidewall with vertical sulcus, curving upward from longitudinal groove to meet anterolateral margin at exorbital tooth, dividing sidewall into three parts. Second antennal segments broad, filling lateral margins of antennular fossae. Exopod of third maxilliped with long flagellum, ischium smooth, lacking vertical sulcus. Thoracic sternal sulcus s 1 / s 2 either faint or absent; thoracic sternal sulcus s 2 / s 3 deep, slightly curved, running horizontally across sternum; thoracic sternal sulcus s 3 / s 4 reduced to two small side notches. Episternal sulci s 4 / e 4, s 5 / e 5, s 6 / e 6, s 7 / e 7 each marked by visible groove. Chelipeds of adult female and subadult male lectotype slim, slightly heterochelous, with long narrow fingers (dactylus, propodus), dactylus not arched, teeth of both fingers small, even. First carpal tooth on inner margin of carpus of cheliped large, slender, pointed, curving forward, second carpal tooth very small (0.25 x first carpal tooth); series of small teeth on outer margin of carpus of P 1. Lateral, medial inferior margins of merus of cheliped faintly granular, single small pointed distal meral tooth superior surface of merus granular. Carpi of P 2 – P 4 with spines on anterior margins, posterior margins smooth; carpus of P 5 with single spine on anterior margin, posterior margin smooth; propodi of P 2 – P 4 with spines on anterior margins, posterior margins smooth; propodus of P 5 with spines on anterior and posterior margins; meri of P 2 – P 5 with two sharp pointed distal teeth; margins of dactyli of P 2 – P 5 with rows of strong spines. P 5 shortest walking leg, propodus P 5 broad, dactylus P 5 very short, about half as long a dactyli of P 2 – P 4. Terminal article of gonopod 1 one­third as long as subterminal segment, terminal article tubular with parallel sides, medial and lateral folds low and even throughout length, tip of terminal article broad, with distinct triangular medial corner; distal margin of subterminal segment of gonopod 1 distinctly indented in middle; dorsal membrane broadest in middle, tapering sharply at both sides, narrowest at lateral, medial margins. Subterminal segment of gonopod 2 broad­based, tapering sharply to long slim process, terminal article of gonopod 2 long, slender, flagellum­like. Erimetopus vandenbrandeni is a small species with an adult size between cw 22.6 and 38 mm. For more details, and illustrations of the type material see Balss (1936, fig. 26), for a description, photographs, and illustrations of other specimens see Bott (1955).	en	Cumberlidge, Neil, Reed, Sadie K. (2004): Erimetopus vandenbrandeni (Balss, 1936) n. comb., with notes on the taxonomy of the genus Erimetopus Rathbun, 1894 (Brachyura: Potamoidea: Potamonautidae) from Central Africa. Zootaxa 422 (1): 1-27, DOI: 10.11646/zootaxa.422.1.1, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.422.1.1
03A88E3DC20D4429546DFA30FB977BA1.taxon	distribution	Distribution. Erimetopus vandenbrandeni is found either in, or near, the Congo River in the vicinity of Kinshasa, D. R. Congo (Fig. 45). Balss (1936) based his description on three lots of specimens, all from Kinshasa, and Bott (1955) reported on two female specimens from Kalima (near Kinshasa) collected by E. Dartevelle in 1948 (MRAC 31998, 32910). This species has a relatively narrow distribution, is not well represented in museum collections, and has not been collected (to our knowledge) since 1935. For these reasons we would judge its conservation status to be in the Critically Endangered category (Red List Criteria A 2) of the Red List Assessment (IUCN 2001).	en	Cumberlidge, Neil, Reed, Sadie K. (2004): Erimetopus vandenbrandeni (Balss, 1936) n. comb., with notes on the taxonomy of the genus Erimetopus Rathbun, 1894 (Brachyura: Potamoidea: Potamonautidae) from Central Africa. Zootaxa 422 (1): 1-27, DOI: 10.11646/zootaxa.422.1.1, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.422.1.1
03A88E3DC20D4429546DFA30FB977BA1.taxon	discussion	Relationships. Erimetopus vandenbrandeni is close to E. brazzae and has a similar subhexagonal carapace outline, similar tooth patterns on the carapace margins and walking legs, a large epibranchial tooth, and a long, toothed anterolateral margin of the carapace between the exorbital and epibranchial teeth. Erimetopus vandenbrandeni differs from E. brazzae as follows. The carapace of E. vandenbrandeni is conspicuously flattened (it is of medium height in E. brazzae), the second carpal tooth on the inner margin of the carpus of the cheliped of E. vandenbrandeni is small (this tooth is large in E. brazzae), and the superior margins of the meri of the walking legs P 2 – P 5 have dense hair­like setae (these margins lack setae in E. brazzae). In addition, the vertical groove on the carapace sidewall of E. vandenbrandeni meets the base of the epibranchial tooth (this groove is not directed toward the epibranchial tooth in E. brazzae); there is a deep sinus on the anterolateral margin just anterior to the epibranchial tooth in E. vandenbrandeni (this sinus is lacking in E. brazzae), and the frontal margin of of E. vandenbrandeni is straight (this margin is distinctly indented in E. brazzae). Erimetopus vandenbrandeni shares characters such as a straight frontal margin, and a row of hair­like setae on the meri of P 2 – P 5 with P. (E.) b. frontospinulosa. However, E. vandenbrandeni can be easily distinguished from P. (E.) b. frontospinulosa by the same characters outlined above that distinguish E. vandenbrandeni from E. brazzae. Remarks. Only a single subadult male specimen (cw 16.8 mm) of E. vandenbrandeni is known (Figs. 27 – 35, 39 – 45). The gonopods of E. vandenbrandeni were not illustrated by Balss (1936) in the original description of this species, but gonopod 1 of the male of E. vandenbrandeni was sketched by Bott (1955: 22 A), although Bott did not list this specimen in the material examined section of his work. Gonopod 1 of the male of E. vandenbrandeni from Kinshasa is shown in more detail in the present study (Figs. 31 – 33, 42 – 44), and gonopod 2 of this species is illustrated here for the first time (Figs. 34 – 35). The general form of gonopods 1 and 2 of E. vandenbrandeni is the same as that found in the Old World potamonautid and potamid freshwater crabs (Bott 1955, 1970; Cumberlidge 1999). For example, gonopod one is in four parts that include a relatively well­developed terminal article and a broad dorsal membrane. This also describes the general organization of the first gonopod of a number of African genera such as Potamonautes, Liberonautes, Sudanonautes, Potamonemus, Louisea, Afrithelphusa, Globonautes, Platythelphusa, and Deckenia (Cumberlidge 1999). Similarly, gonopod two is in four parts that include a relatively well­developed flagellum­like terminal article. These characteristics also describe the general organization of the second gonopod of African genera such as Potamonautes, Liberonautes, Louisea, Afrithelphusa, Platythelphusa and Deckenia (Cumberlidge 1999). Bott (1955) assigned E. vandenbrandeni to Potamonautes (Longipotamonautes) on the basis of perceived similarities between the shape of the terminal article of gonopod 1 in E. vandenbrandeni and Potamonautes ballayi (A. Milne­Edwards, 1887) (the type­species of the subgenus Longipotamonautes Bott, 1955). Although the terminal article of gonopod 1 of P. ballayi has a broad tip that is somewhat similar to that of E. vandenbrandeni, the terminal article in P. ballayi is distinctly tapered (which is typical of Potamonautes), rather than tubular and hose­like, as in E. vandenbrandeni. Moreover, the first gonopod of E. vandenbrandeni (Figs. 31 – 33, 42 – 44) differs from P. ballayi in other characters such as the shape of the dorsal membrane, the shape of the distal margin of the subterminal segment, and the position and definition of the longitudinal (seminal) groove of the terminal article (Capart 1954; Bott 1955, fig. 23). It should be noted that the hose­like terminal article of the first gonopod of E. vandenbrandeni is neither identical to, nor close in organization to, the strongly­tapered terminal article of the more than 60 species of Potamonautes that we are familiar with. Moreover, P. ballayi (which is the species of Potamonautes that is closest to E. vandenbrandeni according to Bott (1955 )) is in fact distinctly different from Erimetopus when non­gonopod diagnostic characters of the carapace, pereopods and mouthparts are considered (Bott 1955). For example, like all species of Potamonautes, P. ballayi lacks teeth on the anterolateral margin of the carapace between the exorbital and epibranchial teeth, lacks teeth on the outer margin of the carpus of the cheliped, and lacks teeth or setae on the margins of the carpi and propodi of the walking legs (P 2 – P 4). In addition, P. ballayi can be further distinguished from Erimetopus by the former taxon’s lack of teeth on the anterolateral margin behind the epibranchial tooth, by a distinctly arched dactylus of the major cheliped, and by a complete and deep sternal sulcus s 3 / s 4. There are only a few other species of freshwater crabs in Africa with a noticeably flat carapace similar to that found in E. vandenbrandeni. Examples include the completely aquatic lake­living crab Platythelphusa maculata (ch / fw 0.9) and the West African river crab Liberonautes chaperi (ch / fw 0.9) (Cumberlidge et al. 1999; Cumberlidge 1999). In general, African freshwater crabs with a flat carapace tend to be completely aquatic river or lake dwellers that rarely, if ever, breathe air at any point in their life cycle (Cumberlidge 1999). It remains to be seen whether this generalization applies to E. vandenbrandeni, and the answer to questions such as this must await data from new field collections in the lower Congo River. Given the current long­term political unrest in Central Africa, it may be a very long time before anyone is in a position to collect thoroughly enough to obtain a series of male specimens of any species of this interesting genus.	en	Cumberlidge, Neil, Reed, Sadie K. (2004): Erimetopus vandenbrandeni (Balss, 1936) n. comb., with notes on the taxonomy of the genus Erimetopus Rathbun, 1894 (Brachyura: Potamoidea: Potamonautidae) from Central Africa. Zootaxa 422 (1): 1-27, DOI: 10.11646/zootaxa.422.1.1, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.422.1.1
