taxonID	type	description	language	source
038987A0FFE7A6617785FA3AFBA7FE34.taxon	description	(Figs. 2 – 4)	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
038987A0FFE7A6617785FA3AFBA7FE34.taxon	materials_examined	Type material. Holotype: Guinea Bissau. GB 1219, Stn L 53, 10 ° 01 ' 55 " N, 17 ° 25 ' 01 " W, 909 m, 30 November 2019: ovigerous female 5.8 mm (ICM-CBMR-D 002846), sequenced, GenBank Acc. No. PQ 654352.	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
038987A0FFE7A6617785FA3AFBA7FE34.taxon	description	Description. Carapace: Broader than long (length 0.8 × breadth); greatest breadth 1.9 × distance between anterolateral spines. Dorsal surface nearly smooth, moderately convex from side to side and anterior to posterior. Lateral margin convexly divergent posteriorly, with fine granulations supporting fine setae, not ridged along posterior portion. Anterolateral spine well developed, directed straight forward, situated very slightly posterior to small lateral orbital spine, and separated from that spine by its basal breadth, slightly overreaching base of antennal scale. Rostrum sharp, triangular, with interior angle of 22 °, nearly horizontal, directed anteriorly; dorsal surface flattish, length 1.5 × breadth, 0.6 × length of remaining carapace, breadth 0.4 that of carapace measured at posterior margin. Pterygostomian flap smooth on surface, anteriorly somewhat roundish with tiny spine. Thoracic sternum: Excavated sternum anteriorly convex, surface weakly convex from side to side. Sternal plastron broader than long (length three-quarters breadth); lateral extremities somewhat divergent posteriorly between sternites 4 and 6, subparallel between sternites 6 and 7. Sternite 3 weakly depressed in ventral view, anterior margin moderately excavated with median notch lacking flanking spine, anterolaterally minutely dentate; small spine at lateral terminus. Sternite 4 anterolateral margin convexly divergent posteriorly, anteriorly irregular, not produced into spine; length 1.5 × that of posterolateral margin. Anterolateral margin of sternite 5 convex, slightly longer than posterolateral margin of sternite 4. Pleon: Smooth and glabrous. Pleomere 1 moderately convex from anterior to posterior. Pleomere 2 tergite 2.8 × broader than long, pleuron with lateral margin concavely divergent posteriorly, blunt at posterolateral terminus. Pleura of pleomeres 3 – 5 posterolaterally blunt. Telson 0.4 × as long as broad, slightly constricted between anterior and posterior plates; posterior plate as long as anterior plate, moderately concave on posterior margin. Eye: Globular, as long as broad, barely reaching proximal one-third of rostrum. Cornea not dilated, subequally long as remaining eyestalk. Antennule and antenna: Ultimate article of antennule 3.9 × longer than high. Antennal peduncle overreaching eye, reaching midlength of rostrum. Article 2 with small but distinct distolateral spine. Antennal scale overreaching article 5 by basal segment of flagellum, breadth 2.4 × that of article 5, 0.5 × height of ultimate antennular article. Article 4 unarmed. Article 5 with very small distomesial spine; length 1.6 × that of article 4. Flagellum of 15 segments not reaching distal end of P 1 merus, overreaching rostrum by more than one-third of its length, shorter than (0.8 ×) rostrum, 1.9 × length of articles 4 and 5 combined. Mxp: Mxp 1 with bases widely separated from each other. Mxp 3 basis lacking distinct denticles on mesial ridge. Ischium crista dentata with about 30 very small denticles, flexor margin not rounded distally. Merus 2.4 × longer than ischium, mesial face distally flattish, flexor margin with 3 small spines distal to midlength, distolateral spine obsolete. No spine on carpus. P 1: 4.5 × longer than carapace, setose, ventral surface finely granulose on merus and carpus, smooth on palm. Ischium with small dorsal spine, ventromesially with obsolescent subterminal spine. Merus 1.1 × longer than carapace, with 2 distomesial (mesiodorsal and mesioventral) and 1 small distolateral ventral spine; dorsal surface spineless, distal margin minutely denticulate. Carpus subcylindrical, 1.2 × longer than merus, dorsally with minutely denticulate distal margin, ventrally with well-developed distomesial and small distolateral spine. Palm 1.1 × length of carpus, 4.5 × longer than broad, slightly depressed (height 0.8 × breadth). Fingers not gaping, 0.4 × length of palm, each ending in strongly incurved distal spine; opposable margin of movable finger with rounded proximal process, that of fixed finger sinuous. P 2 – 4: Setose as on P 1; unarmed on meri and carpi. Meri successively shorter posteriorly (P 3 merus 0.9 × length of P 2 merus, P 4 merus 0.8 × length of P 3 merus). P 2 merus shorter than carapace (0.9 ×), 1.1 – 1.2 × longer than P 2 propodus, P 3 merus as long as P 3 propodus, P 4 merus 0.8 × length of P 4 propodus; length-breadth ratio, 4.8 on P 2, 4.3 on P 3, 3.5 on P 4. Carpi successively shorter posteriorly, shorter than propodi (carpus-propodus length ratio, 0.6 on P 2, 0.5 on P 3 and P 4), longer than dactyli (carpus-dactylus length ratio, 1.4 on P 2, 1.3 on P 3, 1.1 on P 4). Propodi subequally long on P 2 and P 4, slightly longer on P 3; flexor margin moderately convex distally, with pair of terminal spines preceded by 7 or 8 basally articulated, long spines on P 2, 7 spines on P 3 and P 4. Dactyli subequally long on P 3 and P 4, slightly shorter on P 2, somewhat curving, length 0.4 × that of propodus, flexor margin with 9, somewhat obliquely directed, triangularly elongate, stout spines, distal 6 or 7 spines subequal, proximal spines successively smaller. Eggs: Number of eggs carried, 20; size 1.10 × 1.39 mm to 1.16 × 1.32 mm.	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
038987A0FFE7A6617785FA3AFBA7FE34.taxon	biology_ecology	Genetic data. Interspecific sequence divergence (COI):> 15 % (U. nitidus, sequenced in this study); COI:> 15 % (U. rubrovittatus, sequenced in this study). See phylogenetic tree (Fig. 1).	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
038987A0FFE7A6617785FA3AFBA7FE34.taxon	etymology	Etymology. From the Greek pauros (little) plus optilus (eye), referring to the small eye of the species.	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
038987A0FFE7A6617785FA3AFBA7FE34.taxon	discussion	Remarks. Among the six species of Uroptychus so far known from the eastern Atlantic (Baba & Macpherson 2017), the following two species resemble U. pauroptilus sp. nov. in the carapace shape including the relatively long, sharply triangular rostrum, lack of submedian spines on the thoracic sternite 3 and the spination of the P 2 – 4 dactyli: U. maroccanus Türkay, 1976 from off the coast of Morocco and U. tuerkayi Baba & Macpherson, 2017 from the Atlantis-Great Meteor Seamount Chain south of the Azores Islands. The original description of U. maroccanus is rather brief, but additional morphological details were obtained by Baba & Macpherson (2017). Uroptychus pauroptilus sp. nov. is clearly distinguishable from U. maroccanus in the following differences: the lateral orbital spine is much smaller than, instead of well developed and larger than the anterolateral spine of the carapace; the carapace dorsum is almost smooth, instead of bearing small spines at least along the lateral margin; the pterygostomian flap is anteriorly somewhat roundish with a tiny spine, instead of being angular with a strongly produced spine; the excavated sternum is anteriorly rounded, followed by a weak median ridge, instead of being anteriorly sharp triangular, followed by carinate ridge in midline; antennal article 5 bears a small, rather than strong distomesial spine; the antennal scale overreaches article 5, instead of terminating at most at the midlength of that article; the P 1 merus and carpus are dorsally almost spineless, instead of spinose; the P 2 – 4 propodal flexor margins are distally convex, rather than nearly straight; the ultimate spine of the P 2 – 4 dactyli is subequal to the penultimate, instead of distinctly smaller. Uroptychus tuerkayi resembles U. maroccanus (see Baba & Macpherson 2017), and the above listed distinguishing characters between U. maroccanus and U. pauroptilus are partly applicable to between U. pauroptilus and U. tuerkayi. Uroptychus pauroptilus sp. nov. differs from U. tuerkayi as follows: the lateral orbital spine is small, rather than well developed; the excavated sternum is anteriorly convex, rather than sharply triangular; the eye is globular, as long as broad, instead of being 1.4 – 1.6 times longer; the antennal article 5 bears a tiny, rather than strong distomesial spine; the antennal scale overreaches the tip of, instead of terminating at most at the midlength of article 5; the antennal flagellum is long, exceeding far beyond the apex of rostrum, instead of being short, at most slightly overreaching the rostrum; the third maxilliped merus bears a few small but distinct spines distal to the midlength of the flexor margin, instead of being unarmed; the P 1 merus and carpus are dorsally smooth, rather than spinose; the P 2 – 4 meri are dorsally unarmed, rather than spinose; and the P 2 – 4 propodal flexor margins are distally convex, rather than straight. Unfortunately, molecular data for species of Uroptychus is scarce and any genetic comparison should be considered with caution. However, the new species is clustered with other species from the Western Pacific (Fig. 1), although with high genetic divergences ranging from 17 to 21 %.	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
038987A0FFE7A6617785FA3AFBA7FE34.taxon	distribution	Distribution. Only known from the type locality, off Guinea Bissau, at 909 m.	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
038987A0FFEDA6657785FD80FB55F863.taxon	description	(Figs. 5 – 7)	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
038987A0FFEDA6657785FD80FB55F863.taxon	materials_examined	Type material. Lectotype: Martinique, BLAKE Stn 200, 14 ° 31 ' 55 " N, 61 ° 07 ' 28 " W, 863 m, 7 February 1879: female 7.1 mm (MCZ CRU- 2756) [examined]. Other material examined (eastern Atlantic). Guinea Bissau. GB 1219 Stn L 53, 10 ° 01 ' 55 " N, 17 ° 25 ' 01 " W, 909 m, 30 November 2019: 1 male 13.5 mm (carapace broken, ICM-CBMR-D 002842, sequenced, GenBank Acc. No. PQ 654351), 3 ovigerous females 9.6 – 11.9 mm (ICM-CBMR-D 002843). Sierra Leone, off Freetown. GALATHEA Stn 17, 7 ° 17 ' N, 13 ° 28 ' W, 1290 m, mud, 10. XI. 1950: 2 males 9.3 mm, another male not measured (ZMUC CRU- 11635). Other material examined (western Atlantic). Bahamas, Global Explorer ROV, F. G. Walton Smith R / V, Stn NWP 101 – bb, 25 ° 51 ' 41.73 " N, 77 ° 16 ' 57.41 " W, 1731 m, 27 March 2009: 1 ovigerous female 8.7 mm (USNM 1532599, sequenced, GenBank Acc. No. PQ 654359). — Gulf of Mexico, Louisiana, R / V Pelican Stn GoMRI-III- 02, 27 ° 34 ' 8.46 " N, 89 ° 50 ' 15.45 " W, 1125 – 1148 m, 16 November 2012: 1 male 6.8 mm (USNM 1532600, sequenced, GenBank Acc. No. PQ 654360). — Florida, R / V PELICAN Stn GoMRI-V- 28, 24 ° 20 ' 51.50 " N, 83 ° 54 ' 28.45 " W, 1200 m, 11 September 2014: 1 male 4.8 mm (USNM 1532601, sequenced, GenBank Acc. No. PQ 654361). — Caribbean Sea, Colombia, R / V OREGON, Cruise 92 Stn 4913, 12 ° 09 ' N, 72 ° 47 ' W, 183 m, 01 June 1964: 1 male 9.2 mm (USNM 1662453, sequenced, GenBank Acc. No. PQ 654362). Comparative material. Uroptychus concolor (A. Milne Edwards & Bouvier, 1894): Off the coast of Sahara [now Western Sahara], TALISMAN Stn 80, 23 ° 52 ' N, 19 ° 37 ' W [Greenwich longitude 17 ° 17 ' W], 1139 m: lectotype, male 10.9 mm (MNHN Ga 507 [currently MNHN-IU- 2016 - 534]). NW Spain, Bank of Galicia. INDEMARES Stn GOC 8, 42 ° 37 ' 59.88 " N, 11 ° 28 ' 59.88 " W, 1565 m, 25 July 2011: 1 ovigerous female 7.2 mm (ICM-CBMR-D 000322), sequenced, GenBank Acc. No. PQ 65435, 1 female 8.0 mm (ICM-CBMR-D 000324), sequenced, GenBank Acc. No. PQ 654358; 1 female 9.0 mm (ICM-CBMR-D 000323), sequenced, GenBank Acc. No. PQ 654357. — Stn DR 31, 42 ° 58 ' 59.88 " N, 11 ° 57 ' 59.76 " W, 1671 m, 25 July 2011: 1 male 13.1 mm (ICM-CBMR-D 000282), sequenced, GenBank Acc. No. PQ 654353, 2 ovigerous female 9.6 (ICM-CBMR-D 000283), sequenced, GenBank Acc. No. PQ 654354, 11.8 mm (ICM-CBMR-D 000284), sequenced, GenBank Acc. No. PQ 654355. Atlantis Seamount. SEAMOUNT 2, Stn DW 261, 34 ° 22.37 ’ N, 30 ° 27.79 ’ W, 1190 – 1340 m, 03 February 1993: 3 males 7.4 – 12.0 mm (CEAB-CRU 1993 A). — Stn DW 262, 34 ° 23.36 ’ N, 30 ° 29.06 ’ W, 1000 – 1160 m, 03 February 1993: 6 males 6.1 – 13.6 mm; 2 ovigerous females 10.5, 11.7 mm (CEAB-CRU 1993 B).	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
038987A0FFEDA6657785FD80FB55F863.taxon	biology_ecology	Genetic data. Intraspecific sequence divergence (COI): 1.5 % (western and eastern Atlantic specimens). Interspecific sequence divergence is on average: 6 % (U. concolor); 15 % (U. rubrovittatus) (see Fig. 1).	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
038987A0FFEDA6657785FD80FB55F863.taxon	discussion	Remarks. The taxonomic status of Uroptychus nitidus was verified by Baba & Wicksten (2017 a), based on examination of all syntypes and a large series of specimens from the western Atlantic. Morphologically, the present specimen from Guinea Bissau is only slightly different from the western Atlantic specimens in the ornamentation of the carapace dorsum (Fig. 5): small tubercles are scattered on the lateral surface in small specimens or distributed all over the surface in large specimens (versus obsolescent or nearly absent). However, molecular data indicate that the genetic distance (COI gene) between the western and eastern Atlantic specimens is minor at around 1.5 % (Fig. 1), which suggests that this morphological variability is merely intraspecific. Among the squat lobster collection of the Galathea Expedition made available to KB (cf Baba 2005), two specimens taken at Station 17 off Freetown, Sierra Leone (ZMUC CRU- 11635) were provisionally identified as Uroptychus nitidus considering its range was presumed to be restricted to the western Atlantic (Baba, unpubl.). This material was not included in that report, which treated the Indo-Pacific species. This identification of the Guinea Bissau specimen is now accepted, being corroborated by the present molecular analysis. Uroptychus nitidus resembles U. concolor (A. Milne Edwards & Bouvier, 1894) from the northeastern Atlantic, which was originally described as Diptychus nitidus var. concolor A. Milne Edwards & Bouvier, 1894. Chace (1942) noted that U. nitidus can be separated from U. concolor by the depressed P 1, the carpus in particular; the height-breadth ratio of the P 1 carpus is 0.6 – 0.7 in U. nitidus (see Baba & Wicksten 2017 a), 0.8 in U. concolor (in accordance with the material here examined). A further diagnostic character is proposed here considering the relative size of the ultimate compared to penultimate spine of the P 2 – 4 dactyli: the ultimate spine is subequal to the penultimate in U. nitidus (see Baba & Wicksten 2017 a: fig. 2 F, H, J; Fig. 7 C, F, H in this paper), distinctly smaller in U. concolor (Figs. 8 H, 11 B, 11 D, 11 F), the latter confirmed by examination of the lectotype and additional material from off northeastern Atlantic. The genetic distance between U. nitidus and U. concolor is on average 6 % for COI, and these species are highly divergent from U. rubrovittatus (15 %) (Fig. 1).	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
038987A0FFEDA6657785FD80FB55F863.taxon	distribution	Distribution. Gulf of Mexico, Caribbean Sea, and Brazil. The present material extends its range to the western coast of Africa. The specimens from the coasts of Guinea Bissau and Sierra Leone were collected at 909 – 1290 m. The occurrences in the West Atlantic range between 161 and 1362 m (Baba & Wicksten 2017 a).	en	Baba, Keiji, Macpherson, Enrique, Rodríguez-Flores, Paula C. (2025): New records of the squat lobster genus Uroptychus (Crustacea: Decapoda: Anomura: Chirostylidae) from West Africa: unexpected occurrence of the western Atlantic species U. nitidus (A. Milne Edwards, 1880) and description of a new species. Zootaxa 5627 (1): 128-146, DOI: 10.11646/zootaxa.5627.1.4, URL: https://doi.org/10.11646/zootaxa.5627.1.4
