taxonID	type	description	language	source
0B672D56132FF71B9FE9FC7488756793.taxon	description	urn: lsid: zoobank. org: act: CBEA 1 E 45 - 7 B 27 - 4 FD 1 - 873 A- 404 A 0 F 86040 C (Figs. 2 – 6)	en	Galván-Villa, Cristian M., Salgado-Barragán, José (2026): Liropus tenebris, a new species of caprellid (Crustacea: Amphipoda) from the middle mesophotic zone of Bahía de Banderas, Mexican Pacific. Zootaxa 5845 (2): 340-352, DOI: 10.11646/zootaxa.5845.2.7, URL: https://doi.org/10.11646/zootaxa.5845.2.7
0B672D56132FF71B9FE9FC7488756793.taxon	materials_examined	Material examined: Holotype: male, (TL 6.63 mm), Majahuitas, Bahía de Banderas, Jalisco, Mexico (20 ° 30 ' 27 " N, 105 ° 23 ' 31 " W), Feb 15, 2020, 70 m depth, rocky substrate covered with gorgonians [Leptogorgia alba (Duchassaing & Michelotti) and Leptogorgia regis Hickson] (EMU- 13950). Paratypes: same data as holotype, 8 males (4.2 – 8.0 mm) and 11 females (3.9 – 4.9 mm) (EMU- 13951); 2 males (3.2 – 4.6 mm) and 2 females (3.1 – 3.9 mm), same data as holotype (CNCR 38679). 6 males (1.8 – 2.6 mm), 1 female (2.5 mm), same locality, Sept 7, 2019, 60 m depth, from sponges (Dragmacidon sp.) (LEMA-CCR 833). Additional material: S ame data as holotype, 33 males, 34 females, 17 juveniles (EMU- 13952). 4 males, 6 females, and 5 juveniles, Los Arcos, Bahía de Banderas, Jalisco, Mexico (20 ° 32 ' 50 " N, 105 ° 17 ' 29 " W), Feb 16, 2020, 60 m depth, from gorgonians (Ellisella limbaughi Bayer and L. regis) (LEMA-CCR 834).	en	Galván-Villa, Cristian M., Salgado-Barragán, José (2026): Liropus tenebris, a new species of caprellid (Crustacea: Amphipoda) from the middle mesophotic zone of Bahía de Banderas, Mexican Pacific. Zootaxa 5845 (2): 340-352, DOI: 10.11646/zootaxa.5845.2.7, URL: https://doi.org/10.11646/zootaxa.5845.2.7
0B672D56132FF71B9FE9FC7488756793.taxon	diagnosis	Diagnosis. Head simple, without projections; eyes present, barely distinguishable; antenna 1 flagellum five-articulate in males, three-articulate in females; antenna 2 flagellum two-articulate; body dorsally smooth; pereonite 2 with a pair of anterolateral projections in males; gnathopod 2 basis slightly curved, smooth as long as pereonite 2; pereopods 3 and 4 one-articulate; pereopod 5 two-articulate; abdomen without appendages in males.	en	Galván-Villa, Cristian M., Salgado-Barragán, José (2026): Liropus tenebris, a new species of caprellid (Crustacea: Amphipoda) from the middle mesophotic zone of Bahía de Banderas, Mexican Pacific. Zootaxa 5845 (2): 340-352, DOI: 10.11646/zootaxa.5845.2.7, URL: https://doi.org/10.11646/zootaxa.5845.2.7
0B672D56132FF71B9FE9FC7488756793.taxon	etymology	Etymology. The specific name tenebris, refers to darkness in Latin, due to the low light condition where the new species were found.	en	Galván-Villa, Cristian M., Salgado-Barragán, José (2026): Liropus tenebris, a new species of caprellid (Crustacea: Amphipoda) from the middle mesophotic zone of Bahía de Banderas, Mexican Pacific. Zootaxa 5845 (2): 340-352, DOI: 10.11646/zootaxa.5845.2.7, URL: https://doi.org/10.11646/zootaxa.5845.2.7
0B672D56132FF71B9FE9FC7488756793.taxon	distribution	Distribution. Only known at two localities of Bahía de Banderas [Majahuitas (type locality) and Los Arcos], Jalisco, Mexico.	en	Galván-Villa, Cristian M., Salgado-Barragán, José (2026): Liropus tenebris, a new species of caprellid (Crustacea: Amphipoda) from the middle mesophotic zone of Bahía de Banderas, Mexican Pacific. Zootaxa 5845 (2): 340-352, DOI: 10.11646/zootaxa.5845.2.7, URL: https://doi.org/10.11646/zootaxa.5845.2.7
0B672D56132FF71B9FE9FC7488756793.taxon	description	Description. Holotype, male (6.3 mm) (Figs. 2, 3). Body dorsally smooth; head rounded, lacking any projections, eyes with barely distinguishable ommatidia; pereonites smooth, subcylindrical; pereonite 1 fused with the head, suture present; pereonite 2 with anterolateral projections; pereonites 3 and 4 of similar length; pereonites 3, 5, and 6 with distodorsal projection; pereonite 5 the longest; pereonite 7 the shortest. Gills (Fig. 3). Present at the middle of pereonites 3 – 4, similar, elongate, length about 3 times width. Mouthparts (Fig. 4). Mandibles with developed triturative molar, marginally dentate, palp of mandible three-articulate, second article the longest, provided with a single medial seta, distal article ending in 9 to 11 plumose setae, setal formula: 1 - x- 1, being x = 7 – 9, incisor and lacinia mobilis five-dentate, followed by three accessory blades; molar partially surrounded by short, blunt spines, molar flake not seen. Upper lip symmetrically bilobate, without setae. Maxilla 1 outer lobe with seven distal cuspidate setae, palp two-articulate, distal article of palp with two apical and one subapical seta. Maxilla 2 inner lobe shorter than outer lobe, with two apical setae, outer lobe with four apical setae. Maxilliped inner plate rectangular carrying two apical setae, outer lobe oval, 2.1 times as long as inner lobe, with a row of four setae, palp four-articulate, scarcely setose, article 1 without setae, article 2 with one subdistal seta, article 3 with three distal setae, article 4 the longest, slightly curved, acute, with one subdistal spine and tiny mesiodistal setulae. Antennae (Fig 5). Antenna 1 about 1.8 times antenna 2; peduncular article 1 the shortest, peduncular article 2 the largest; flagellum five-articulate, each article with a row of distal setae; peduncular article 1 the shortest; peduncular article 2 the largest. Antenna 2; basal article with acute frontodistal projection; flagellum two-articulated, with sparse setae an ending in apical setae. Gnathopods (Fig 5). Gnathopod 1 basis curved, about 1.2 times larger than ischium, merus, and carpus combined; ischium with 2 ventrodistal setae; merus larger than ischium, with 3 – 4 submedian setae and 2 mesial long simple setae; carpus subquadrate, with a long median simple seta and 5 distomesial long simple setae; propodus triangular, grasping margin smooth, external face with several ventromarginal and one distal setae, mesial face with one proximal spinelike seta, several ventromarginal seta and an oblique row of 6 median long simple setae, dactylus distally bifid. Gnathopod 2 inserted on the anterior half of pereonite 2; basis slightly curved with two ventrodistal setae, smooth, as long as pereonite 2; ischium rectangular with one ventral seta; merus rounded with several ventral setae; carpus short and triangular; propodus oval as long as basis, palm with proximal projection provided with one large grasping cuspidate seta, cutting edge setose, minutely serrate margin with larger distal denticles, and a small U-shaped notch; dactylus smooth and elongate, inner margin with sparse minute setae. Pereopods (Fig. 6). Pereopod 3 and 4 one-articulate, with two distal setae. Pereopod 5 two-articulate, inserted at the middle of pereonite 5, proximal article about 0.5 as long as distal one with one long medial seta, distal article with five or six distal setae. Pereopods 6 and 7 similar, P 6 slightly shorter than P 7, six-articulate; basis long without carina; ischium short and rectangular; merus thickened distally, sparsely setose; carpus longer than merus, ventral margin with row of 6 – 7 ventral and 2 – 3 dorsal curved setae and a long dorsodistal plumose seta; propodus the longest, ventral margin with 1 – 2 proximal grasping cuspidate setae, and a row of 12 – 15 shorter curved setae, dorsal margin with 5 – 7 setae; dactylus with one proximodorsal plumose seta, elongated, curved, tip acute; Pereopod 7 similar but slightly larger than pereopod 6; merus less thickened distally than those in P 6. Penes (Fig. 6). Large, medially located, sub rectangular, distally rounded with 4 setae. Abdomen (Fig. 6). Lacking appendages, a pair of lobes. Paratype female (Figs. 2, 3, 5, and 6). Similar, but smaller than males; antennae flagellum with 3 (occasionally 4) articles; pereonite 2 lacking anterolateral projections; oostegites on pereonites 3 – 4; cutting edge of propodus of gnathopod 2 without a distal U-shaped notch; abdomen with a pair of lateral lobes without setae and with a single dorsal lobe.	en	Galván-Villa, Cristian M., Salgado-Barragán, José (2026): Liropus tenebris, a new species of caprellid (Crustacea: Amphipoda) from the middle mesophotic zone of Bahía de Banderas, Mexican Pacific. Zootaxa 5845 (2): 340-352, DOI: 10.11646/zootaxa.5845.2.7, URL: https://doi.org/10.11646/zootaxa.5845.2.7
0B672D56132FF71B9FE9FC7488756793.taxon	biology_ecology	Habitat. Associated with octocorals (Leptogorgia alba, L. regis, and Ellisella limbaughi) and sponges (Dragmacidon sp.) from vertical rocky walls at 60 – 70 m depth.	en	Galván-Villa, Cristian M., Salgado-Barragán, José (2026): Liropus tenebris, a new species of caprellid (Crustacea: Amphipoda) from the middle mesophotic zone of Bahía de Banderas, Mexican Pacific. Zootaxa 5845 (2): 340-352, DOI: 10.11646/zootaxa.5845.2.7, URL: https://doi.org/10.11646/zootaxa.5845.2.7
0B672D56132FF71B9FE9FC7488756793.taxon	discussion	Remarks. Liropus tenebris sp. nov. represents the fourth species of the genus described in the Eastern Pacific and the third for the Mexican coasts; L. minusculus have been recorded from the northeast Pacific (California, USA), L. isabelensis in the Gulf of California (Sinaloa-Nayarit, Mexico) (Sánchez-Moyano et al. 2015; Alarcón-Ortega et al. 2017 a, b), and L. alarconi from Puerto Vallarta in the Mexican Tropical Pacific (Alarcon & Carballo 2022). Morphological diagnostic characters of the regional Liropus species are compared in Table 1. Liropus tenebris sp. nov. can be distinguished from L. minusculus and from L. isabelensis because the cutting edge of the propodus of the male gnathopod 2 is convex, instead of concave and the new species possesses longer and elongated, similar in size, branchiae on pereonites 3 – 4 of both sexes instead of round and reduced on pereonite 4. On the other hand, the new species differs from L. alarconi because it doesn´t have dorsal projections on pereonites, its antennal and antenular peduncles do not have noticeably swollen articles and by having the flagellum of antenna 1 with more than two articles. Both species share Bahía de Banderas as type locality but they were collected on different substrates and different depth ranges; L. alarconi was found between 23 – 30 m, associated to the marine sponge Trikentrion helium Dickinson, 1945, a sponge distributed in rocks and reefs at depths of 15 – 30 m (van Soest et al. 2012; Alarcón-Ortega & Carballo 2022), while L. tenebris sp. nov. was found associated to gorgonians of the genus Leptogorgia and the sponge Dragmacidon sp. at a depth of 60 – 70 m. Liropus tenebris sp. nov. is similar to L. azorensis Guerra-García, 2004 in the general shape of body, gnathopod 2 and mouthparts, but they differ because the new species has pereopods 3 and 4 one-articulate instead two-articulate; the minor number of articles of flagellum of antenna 1 (five instead of nine), the propodus of the gnathopod 1 is subtriangular instead of elongate, the male pereonite 2 have a pair of anterolateral projections and the adult female pereonite 6 doesn’t have oostegites. The new species resembles L. minimus Mayer, 1890, by having head smooth, pereopods 3 and 4 one-articulated and pereopod 5 two-articulate (Guerra-García & Hendrycks, 2013); but L. tenebris sp. nov. differs in that it is larger (> 4.5 in males,> 3 in females); presents pereonite 2 with anterolateral projections in males; first article of antenna 1 is shorter than the third basal article; the basis of the gnathopod 2 of L. minimus has a basal constriction that is absent in L. tenebris sp. nov. Although the number of Liropus species is relatively small (17 spp.) compared to other genres such as Caprella (193 spp.) (Horton et al. 2026), the large bathymetric range they exhibit is remarkable. The species of Liropus have been collected from 0 to close 2500 m (Figure 7). Nine species have been recorded from the littoral and sublittoral zone (0 to 200 m) (L. africanus Mayer, 1920, L. alarconi, L. elongatus Mayer, 1890, L. gurui Guerra-García, Chatterjee & Schizas, 2015, L. isabelensis, L. minimus, L. minusculus, L. tenebris sp. nov., and L. vitucoi Guerra-García, Tato & Moreira, 2018). The bathymetric distribution of L. japonicus Mori, 1995 is still unknown due that the only known specimens are those originally collected, and these were obtained from dead coral masses trapped in gill nets used for catch spiny lobsters off Minabe, Japan and, in that moment, depth was not specified (Mori 1995); accordingly, the species must occupy a shallow coral reef environment (<50 m). Six species have been recorded at depths from 200 to 1000 meters (upper bathyal zone): L. beigini Kireev & Golovan, 2024, L. cachuchoensis Guerra-García, Sorbe & Frutos, 2007, L. gracilis Chevreux, 1920, L. guerragarciai Mauro & Serejo, 2015, L. nelsonae Guerra-García, 2003, and L. willyi Guerra-García, Tato & Moreira, 2018; and five species at greater depths (> 1000 m, lower bathyal zone), being L. guerragarciai the species with the deepest record and the greatest depth range (702 to 2433 m, Mauro & Serejo 2014). Other species of caprellids registered in Bahía de Banderas are Aciconula acanthosma Chess, 1989, Caprella mendax Mayer, 1903, Caprella pitu Sánchez-Moyano, García-Asencio & Guerra-García, 2014, and L. alarconi, all of them are distributed between 2 and 30 m depth (Sánchez-Moyano et al. 2015; Alarcón-Ortega et al. 2017 b; Alarcón-Ortega & Carballo 2022). The current register of caprellid species probably underestimate the actual diversity in marine ecosystems. The number of known species is increasing thanks to the ongoing exploration of hard-to-reach habitats. For example, L. tenebris sp. nov. remained unrecorded despite frequent the frequent marine research conducted at Bahía de Banderas, but its specific bathymetric range made it inaccessible to previous expeditions.	en	Galván-Villa, Cristian M., Salgado-Barragán, José (2026): Liropus tenebris, a new species of caprellid (Crustacea: Amphipoda) from the middle mesophotic zone of Bahía de Banderas, Mexican Pacific. Zootaxa 5845 (2): 340-352, DOI: 10.11646/zootaxa.5845.2.7, URL: https://doi.org/10.11646/zootaxa.5845.2.7
