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Halechiniscidae sp. Material examined: 1 specimen (ML: 1 indeterminable gender) Remarks: The single specimen exhibits a peculiar combination of characteristics of both of the genera Halechiniscus Richters, 1908 and Paradoxipus Kristensen & Higgins, 1989. All digits of leg I are of the Paradoxipus - type (i.e. each digit with a proximal suction disc and a distal claw), while the digits of legs II���IV are of the Halechiniscus - type (i.e. each digit bears only a distal claws). This complex pedal morphology places the specimen outside of any known genus. No further evidence as to whether the specimen belongs within Halechiniscinae Thulin, 1928 or Orzeliscinae Schulz, 1963 can be gathered due to unfavorable orientation and unsatisfactory preservation of the slide-mounted specimen., Published as part of P��rez-Pech, Wilbert Andr��s, Jes��s-Navarrate, Alberto De, Demilio, Erica, Anguas-Escalante, Abril & Hansen, Jesper Guldberg, 2020, Marine Tardigrada from the Mexican Caribbean with the description of Styraconyx robertoi sp. nov. (Arthrotardigrada: Styraconyxidae), pp. 492-508 in Zootaxa 4731 (4) on page 496, DOI: 10.11646/zootaxa.4731.4.3, http://zenodo.org/record/3661944, {"references":["Richters, F. (1908) Marine Tardigraden. Zoologischer Anzeiger, 33, 77 - 85.","Kristensen, R. M. & Higgins, R. P. (1989) Marine Tardigrada from the Southeastern United States coastal waters. I. Paradoxipus orzeliscoides n. gen., n. sp. (Arthrotardigrada: Halechiniscidae). Transactions of the American Microscopical Society, 108, 262 - 282. https: // doi. org / 10.2307 / 3226344","Thulin, G. (1928) Uber die Phylogenie und das System der Tardigraden. Hereditas Genetiskt Arkiv, 11, 207 - 266. https: // doi. org / 10.1111 / j. 1601 - 5223.1928. tb 02488. x","Schulz, E. (1963) Uber die Tardigraden. Zoologischer Anzeiger, 171, 3 - 12."]}

Wingstrandarctus corallinus Kristensen, 1984 3 specimens (PM: 2 female, 1 male) Comparative material: 1 specimen reported as Wingstrandarctus by P��rez-Pech et al. (2018) (ML: 1 female) Remarks: Analysis of all three collected specimens and a re-examination of the single Wingstrandarctus of P��rez- Pech et al. (2018) determined that all four individuals represent the species W. corallinus. The set of characters that define the species as determined by Kristensen (1984) are evident including: the presence of cephalic bacterial vesicles, a small, almost circular caudal ala, dorsal mammilliform cuticular sculpture, and the specific shape of the lateral alae., Published as part of P��rez-Pech, Wilbert Andr��s, Jes��s-Navarrate, Alberto De, Demilio, Erica, Anguas-Escalante, Abril & Hansen, Jesper Guldberg, 2020, Marine Tardigrada from the Mexican Caribbean with the description of Styraconyx robertoi sp. nov. (Arthrotardigrada: Styraconyxidae), pp. 492-508 in Zootaxa 4731 (4) on page 497, DOI: 10.11646/zootaxa.4731.4.3, http://zenodo.org/record/3661944, {"references":["Perez-Pech, W. A., Anguas-Escalante A., de Jesus-Navarrete A. & Hansen J. G. (2018) Primer registro generico de tardigrados marinos en costas de Quintana Roo, Mexico. Academia Journals, 4 (10), 1909 - 1912."]}

Dipodarctus sp. 1 specimen (PM: 1 indeterminable gender) Comparative material: 36 specimens reported as Dipodarctus by P��rez-Pech et al. (2018) (ML: gender determinations not attempted) Remarks: The single specimen from Puerto Morelos displays a set of characters that are typical of the genus including: the primary clavae much longer than, and ventral to the lateral cirri; innermost digit (digit 1) on legs I���III slightly shorter than the other digits; and digit 3 slightly longer than the other digits. The specimen is distinguished from all described members of the genus by a set of dorsolateral wing-like structures. The nature of these unique structures requires further investigation pending the recovery of more specimens. The single specimen was determined not to represent the same taxon as those used to establish the generic record of Dipodarctus by Perez-Pech et al. (2018) for Mexico. Re-examination of the latter specimens found that these should be regarded as Halechiniscus cf. perfectus Schulz, 1955 because they correspond to the limited description of that species but digit 3 on leg pairs I���III is slightly longer than the other digits. This digit pattern is characteristic of Dipodarctus as opposed to Halechiniscus, hence the confusion regarding the assignment of the specimens to the former genus by P��rez-Pech et al. (2018). Therefore, only one record for ��� Dipodarctus sp.���, i.e. the present, should be considered as valid for Mexico., Published as part of P��rez-Pech, Wilbert Andr��s, Jes��s-Navarrate, Alberto De, Demilio, Erica, Anguas-Escalante, Abril & Hansen, Jesper Guldberg, 2020, Marine Tardigrada from the Mexican Caribbean with the description of Styraconyx robertoi sp. nov. (Arthrotardigrada: Styraconyxidae), pp. 492-508 in Zootaxa 4731 (4) on page 496, DOI: 10.11646/zootaxa.4731.4.3, http://zenodo.org/record/3661944, {"references":["Perez-Pech, W. A., Anguas-Escalante A., de Jesus-Navarrete A. & Hansen J. G. (2018) Primer registro generico de tardigrados marinos en costas de Quintana Roo, Mexico. Academia Journals, 4 (10), 1909 - 1912.","Schulz, E. (1955) Studien an marinen Tardigraden. Kieler Meeresforschungen, 11, 73 - 79."]}

Megastygarctides sp. 21 specimens (PM: 8 females, 9 males, 4 indeterminable gender) Remarks: A sufficient number of specimens were recovered for both light microscopy (LM) and SEM studies enabling the new species status of these specimens to be confirmed. This taxon will be described in a separate paper together with another undescribed Megastygarctides species recovered during a concurrent study (in prep.) in the same region., Published as part of P��rez-Pech, Wilbert Andr��s, Jes��s-Navarrate, Alberto De, Demilio, Erica, Anguas-Escalante, Abril & Hansen, Jesper Guldberg, 2020, Marine Tardigrada from the Mexican Caribbean with the description of Styraconyx robertoi sp. nov. (Arthrotardigrada: Styraconyxidae), pp. 492-508 in Zootaxa 4731 (4) on page 497, DOI: 10.11646/zootaxa.4731.4.3, http://zenodo.org/record/3661944

Styraconyx robertoi sp. nov. zoobank.org/ urn:lsid:zoobank.org:act: 8F5B8021-6DC8-420C-AD49-2D7FCE95B7CD Material examined: 20 specimens (PM: 1 female, 1 male, 2 indeterminable gender; ML: 1 indeterminable gender; XK: 10 females, 3 males, 2 indeterminable gender) Remarks: The population occurring at Xcalak is designated as the type population. See Description of the New Species Description of the New Species Styraconyx robertoi sp. nov Type Material: Female holotype and 13 paratypes (8 females, 2 males, 3 larvae). Morphometric values for the type population are given in Table 2. Type Locality: reef lagoon, 0.2–1.0 m depth, subtidal zone, Xcalak, Quintana Roo, Mexico Diagnosis: Styraconyx with subterminal mouth cone, pigmented eyespots present. Asymmetric primary clavae and lateral cirri with common pedestal and surrounded basally by common membrane. Lateral cirri not segmented and with asymmetrically expanded base. Lenticular secondary clavae. Cephalic cirri composed of scapus and tubular, flagellar part only, cirrophore and protruding flagellum absent. Peduncles present only on external digits and reaching claw base, internal digits with proximal pads. In males, internal digits with peduncles present only on leg pair IV. Three-pointed claws with strong primary hook, thinner secondary and accessory hook. Claw sheath not covering tip of claw hooks. Sense organs of first leg two-parted, unsegmented spines on second and third leg. Asymmetric papilla with broad base and terminal spine on fourth leg. Dorsal cuticle with grid-like sculpture and fine punctuation. Holotype description. Female (Figs. 2; 3B,D; 4 A–C; 7) with roughly cylindrical body form (139 μm in length) broadest between leg pairs II and III (46 μm) and distinctly narrower (36 μm) at the point of the insertion of cirri E. Eye spots (Figs. 3A,E) visible as congregations of brown pigment granules on each side of the pharyngeal bulb slightly posterior to the pedestals bearing the primary clavae. Pillars highly conspicuous in the dorsal cuticle and to a lesser degree in the ventral cuticle. Twenty-two ribs traverse the dorsal surface at right angles to eight equally spaced longitudinal ribs forming a distinct grid-like pattern (Figs. 2A,B; 7), beginning just posterior to the pedestals bearing the primary clavae and extending to a position slightly anterior to the cirri E. Distinct dorso-caudal region without grid-like sculpture. Instead, two longitudinal ribs occur which originate on either side of the median line and curve slightly toward the lateral sides (Fig. 7). The subterminal mouth cone is short and ends in a smooth, annular dome with a central mouth opening. The buccal tube (16 μm x 2 μm) has a pair of lateral apophyses on each side (Fig. 3E) and stylet supports with a distal swelling. Stylets are long (20 μm) with strong furcae. Pharyngeal bulb (15 μm) with three placoids of equal length (11 μm). Primary clavae, secondary clavae, and a full set of cephalic cirri are present. The primary clava (10 μm) is highly asymmetric and the form appears different depending on the angle in which it is observed (Figs. 4D,F; 5A). Primary clava and lateral cirrus inserted on a common pedestal and surrounded basally by a short, common membrane. Primary clavae with van der Land’s body present at the base. The lateral cirrus (28 μm) is not segmented and has an asymmetrically expanded base, which is fused to the proximal end of the primary clava (Figs. 4D; 5A,B). Ventral lenticular secondary clava (12 μm) inserted antero-laterally to the external cirrus close to the anterior margin of the head (Figs. 3E; 4E,F; 7). The median cirrus (9 μm) is placed dorsally (Figs. 4A; 6A), well back from the ante- rior margin of the head. Internal cirri (13 μm) are dorsal (Figs. 4B; 6B) and more medial than the ventrally inserted external cirri (12 μm) (Figs. 4C; 6C). Except for the lateral cirri, all cephalic cirri (Figs.4 A–C; 6A–C) are two-parted (which can be difficult to recognize in LM) and each composed of a conical scapus and a tapering, flagellar part with a terminal pore. The flagellum is strictly internal and evident in all cephalic cirri except for the lateral cirri. Sense organs present on all legs and inserted coxally. Sense organs of leg pair I (9 μm) two-parted and similar to the cephalic cirri having a conical scapus and a tapering, flagellar part with a terminal pore (Figs. 4G; 6D). On leg pairs II and III the sense organs are simple, without any recognizable segmentation, and resemble the shape of curved spines (Figs. 6E,F). Sense organ of leg pair IV (Figs. 4H,I) consists of a smooth papilla (7 μm) with terminal spine (6 μm), which has a terminal pore. The papilla is asymmetrical, having the postero-lateral portion less curved than the antero-lateral portion. It is inserted with a broad base on a short pedestal and appears hemispherical rather than spherical. Dorso-lateral cirrus E (Figs. 4H,I) inserted on a prominent pedestal. It consists of a short (3 μm), oversized cirrophore (Figs. 4I; 7) and a long, tapering spine (23 μm) without evident accordion-pleated portion. Each leg with evident coxa, femur, tibia and tarsus. Tarsus of all legs bearing four digits of different length with external digits being shorter than internal digits. Peduncles (Figs. 3B) present only inside the external digits and are of the same type as Styraconyx craticulus (Pollock, 1983) reaching the claw bases (see Kristensen & Higgins, 1984). They have a strongly curved basal portion and an enlarged medial portion with two small lateral points (Fig. 8A). The internal digits have thin, proximal pads. All digits bearing three-pointed claws (Figs. 3D,F; 5C) with primary hook, secondary and accessory hook. The primary hook is the strongest. The secondary hook is thinner but slightly longer than primary hook, and accessory hook is the shortest. The tips of all three hooks are free of the claw sheath (Fig. 8A). Seminal receptacles are not evident. The gonopore (Figs. 2C; 5D) is relatively large (6 μm) and consists of a rosette of six cells situated close to the anus. The anus is an undulating slit and composed of two larger lateral lobes and a small anterior lobe (Figs. 2C; 5D). Males. Only 2 males were found. The smaller one measures 112 μm in body length, the larger measures 154 μm. Both males display a peculiar combination of digit characters in having only two peduncles on each foot of leg pairs I–III (similar to the females) and four peduncles on each foot of leg pair IV. On leg pair IV the peduncles of internal digits are rod-shaped and extend from the base of the digits, through the proximal pads, to the claw bases (Fig. 8B). The testes are not evident. The male gonopore is a simple, oval opening situated close to the anus. No other differences between males and females were observed. Larvae. Three larvae were found, all with four claws on each foot and with body lengths of 95 μm, 112 μm and 114 μm. The specimens display larval characters in the shape and size of the primary clava and in the overall body form (Fig. 3C). The primary clavae are asymmetric but shorter (6–8 μm) and less slender than in adults. The head is not well-differentiated from the trunk and the frontal margin appears blunt, whereas in adults it is protruded (Fig. 3A). One of the specimens has four peduncles on the digits of leg pair IV and so is considered to be a male larva. Scanning electron microscopy. The SEM observations of a single specimen confirmed most of the diagnostic features of this species and aided to a better understanding of their true nature. In LM, the claws, and especially their hooks, can look very different depending on their orientation in the preparation (Figs. 3D,F), whereas the three-dimensional SEM image leaves no mistake of interpretation. This applies also to the sense organs where segmentation and terminal pores can be difficult to recognise by LM, but clearly evident with SEM. In this case where both the primary clava and the base of the lateral cirrus are asymmetric, their true shape is only recognizable with SEM (Figs. 5A,B). Not visible in LM but revealed by SEM is a pair of large pores (Fig. 5D) posterior to the gonopore. While their function is unknown, the position close to the gonopore suggests that they are openings of the seminal receptacles. Differential diagnosis. The 14 previously described taxa (13 species and 1 subspecies) of the genus Styraconyx can generally be divided into two major groups (Kristensen & Higgins 1984; D’Addabbo Gallo et al. 1989; Chang & Rho 1998; Bartels et al. 2015); the S. hallasi group and the S. sargassi group. Species in the S. hallasi group have peduncles on two digits (the external) of each leg and claws with reduced accessory hooks, while species in the S. sargassi group (including the type species S. haplocerus Thulin, 1942) have peduncles on all four digits and claws with three hooks of nearly equal size. While females of Styraconyx robertoi sp. nov. should be placed within the S. hallasi group due to the presence of peduncles only on the external digits of legs I–IV and claws with reduced accessory hooks, the unusual digit configuration of the males, i.e. peduncles only on the external digits of legs I–III and peduncles on all four digits of leg IV, complicates the assignment of the new species to either of the two groups. Within the S. hallasi group only Styraconyx kristenseni sensu lato Renaud-Mornant, 1981 has asymmetric primary clavae that are similar to those of the new species. However, S. kristenseni differs from S. robertoi sp. nov. in hav- ing equal sized claw hooks, slender papilla on leg IV with evident cirrophore, and by lacking secondary clavae and the characteristic grid-like dorsal sculpture. Interestingly, the grid-like sculpture of the dorsal cuticle of S. robertoi sp. nov. bears an immediate resemblance to that of S. craticulus and S. craticuliformis Chang & Rho, 1998, both of which belong to the S. sargassi group. This sculpture is the main decisive character differentiating these three species from all other Styraconyx. S. craticuliformis and the new species both differ from S. craticulus by having reduced accessory hooks, a thin common membrane at the base of the primary clavae and lateral cirri, asymmetric primary clavae, and a smooth papilla on leg IV. In summary, Styraconyx robertoi sp. nov. is most similar to S. craticuliformis but can be readily distinguished from it by the number of peduncles, the presence of distinct secondary clavae, and the shape of the papilla on leg IV, which in S. craticuliformis is more spherical. Type Repositories: Holotype (NHMD-633434) and seven paratypes (2 females NHMD-633435–633436, 2 males NHMD-633437–633438, 3 larvae NHMD-633439–633441) are deposited in the Tardigrada collection of the NHMD, Copenhagen. Six paratypes are deposited in the collection at ECOSUR, Quintana Roo, Mexico. Etymology: The species is dedicated to our valued friend, Dr. Roberto Guidetti of the University of Modena and Reggio Emilia, Italy in recognition of his remarkable contributions to the study of tardigrades.

Batillipes sp. 1 specimen (ML: 1 indeterminable gender) Comparative material: 1 specimen reported as Batillipes by P��rez-Pech et al. (2018) (ML: 1 indeterminable gen- der) Remarks: Neither specimen is mounted in a position to allow for proper observation of the toe pattern, which is crucial for species determination (Pollock 1970; Kristensten & Mackness 2000; Santos et al. 2018). The more evident characters shared by both specimens include: a swollen, rounded caudal region; a prominent, round lateral projection between the head and leg pair I and between leg pairs I and II; and a prominent, triangular, lateral projection between leg pairs II and III and between III and IV, the latter of which points posteriorly. The commonality of these characters and the location of collection between the specimens collected by P��rez-Pech et al. (2018) and the present study indicates that they represent the same Batillipes sp.., Published as part of P��rez-Pech, Wilbert Andr��s, Jes��s-Navarrate, Alberto De, Demilio, Erica, Anguas-Escalante, Abril & Hansen, Jesper Guldberg, 2020, Marine Tardigrada from the Mexican Caribbean with the description of Styraconyx robertoi sp. nov. (Arthrotardigrada: Styraconyxidae), pp. 492-508 in Zootaxa 4731 (4) on page 496, DOI: 10.11646/zootaxa.4731.4.3, http://zenodo.org/record/3661944, {"references":["Perez-Pech, W. A., Anguas-Escalante A., de Jesus-Navarrete A. & Hansen J. G. (2018) Primer registro generico de tardigrados marinos en costas de Quintana Roo, Mexico. Academia Journals, 4 (10), 1909 - 1912.","Pollock, L. W. (1970) Batillipes dicrocercus n. sp., Stygarctus granulatus n. sp. and other Tardigrada from Woods Hole, Massachusetts, U. S. A. Transactions of the American Microscopical Society, 89 (1), 38 - 52. https: // doi. org / 10.2307 / 3224613","Santos, E., Rubal, M., Veiga, P., da Rocha, C. M. C. & Fontoura, P. (2018) Batillipes (Tardigrada, Arthrotardigrada) from the Portuguese coast with the description of two new species and a new dichotomous key for all species. European Journal of Taxonomy, 425, 1 - 32. https: // doi. org / 10.5852 / ejt. 2018.425"]}

Subfamily: Florarctinae Renaud-Mornant, 1982 Genus: incertae genus, Published as part of P��rez-Pech, Wilbert Andr��s, Jes��s-Navarrate, Alberto De, Demilio, Erica, Anguas-Escalante, Abril & Hansen, Jesper Guldberg, 2020, Marine Tardigrada from the Mexican Caribbean with the description of Styraconyx robertoi sp. nov. (Arthrotardigrada: Styraconyxidae), pp. 492-508 in Zootaxa 4731 (4) on page 497, DOI: 10.11646/zootaxa.4731.4.3, http://zenodo.org/record/3661944, {"references":["Renaud-Mornant, J. (1982) Sous-famille et genre nouveaux de Tardigrades marins (Arthrotardigrada). Bulletin du Museum National d'Histoire Naturelle, Paris, Serie 4 e, Section A, 1 - 2, 89 - 94."]}

Florarctus yucatanensis sp. nov. is described from the subtidal zone of a reef lagoon located on the Mexican coast of the Yucatán Peninsula. The new species exhibits a wrinkled dorsal cuticle, sculptured alae, and continuous caestus with projections of characteristic position and morphology, by which it is clearly differentiated from all known congeners. Florarctus yucatanensis sp. nov. presents the first observations of a continuous granulated sculpture of the alae, distinct from the typical punctuations formed by cuticular pillars seen among all Florarctus species.

The doryphorus group: 17(2). Claws IV reduced and clearly smaller than claws I���III................................................. D. pilatoi -. Claws IV similar in size or larger than claws I���III.......................................................... 18 18(17). Entire cuticle without sculpture.........................................................................19 -. Cuticle at least partially sculptured...................................................................... 22 19(18). Lunules on internal claws I���III present, on external absent............................................ D. koreanus -. Internal and external claws without lunules............................................................... 20 20(19). Stylet furcae robust, triangular in shape, with the postero-lateral processes rounded but not swollen.......... D. neglectus -. Stylet furcae with swollen postero-lateral processes.........................................................21 21(20). Oral cavity armature visible, and one large dorso-median tooth at the beginning of the buccal tube present, buccal tube 3 ��m or more in width.............................................................................. D. macrodon -. Oral cavity armature absent/not visible under LM, buccal tube less than 3 ��m in width.................... D. doryphorus 22(18). Dorsal cuticle smooth but large granules present on legs IV........................................ D. tergumrudis -. Dorsal cuticle sculptured.............................................................................. 23 23(22). Ventral sculpture present, lunules on claws present, pt of buccal tube width less than 15, eyes present........ D. polynettae -. Ventral sculpture absent...............................................................................24 24(23). Lunules on claws absent, pt of buccal tube external width more than 20, eyes absent..................... D. smokiensis -. Lunules present, those of the internal claws of the first three pairs of legs often could be difficult to see............... 25 25(24). A cuticular bar at the base of the inner claws on the first three pairs of legs present, evident lunules of the inner claws...... ......................................................................................... D. solidunguis -. A cuticular bar at the base of the inner claws on the first three pairs of legs absent.................................26 26(25). Cuticle with a delicate reticulate sculpture of very thin ridges forming a mesh with a tiny tubercle at each crossing, sculptured legs........................................................................................ D. bindae -. Cuticle with an evident reticulated sculpture with mesh slightly irregular in shape and size, delimited by ridges which form a tubercle at each crossing legs not sculptured.................................................... D. amazzonicus, Published as part of P��rez-Pech, Wilbert Andr��s, Anguas-Escalante, Abril, Cutz-Pool, Leopoldo Querubin & Guidetti, Roberto, 2017, Doryphoribius chetumalensis sp. nov. (Eutardigrada: Isohypsibiidae) a new tardigrade species discovered in an unusual habitat of urban areas of Mexico, pp. 345-356 in Zootaxa 4344 (2) on pages 353-354, DOI: 10.11646/zootaxa.4344.2.9, http://zenodo.org/record/1043140

Doryphoribius chetumalensis sp. nov. Description of holotype (Figs 2–4; Table 2). Body colour orange. Cuticle of dorsal and ventral surfaces, and legs, smooth (i.e. without gibbosities or sculpture; Fig. 2). Eye spots present (Figs 2C, 3A). Bucco-pharyngeal apparatus of Doryphoribius type (see: Pilato & Binda 2010; Guidetti et al. 2013b) (Fig. 3). Peribuccal structures and oral cavity armature absent or not visible under LM. Mouth antero-ventral. Ventral lamina present. Stylet furca of typical shape with two condyles and two proximal apophyses. Pharyngeal bulb spherical, with triangular pharyngeal apophyses, and three macroplacoids, without constrictions, and of similar length; microplacoid and septulum absent. Macroplacoids bean-shaped in lateral view; in dorsal view, the first triangular-shaped, the second rectangular-shaped, the third heart-shaped (Fig. 3). First and second macroplacoids close together, the third macroplacoid more distant. Claws long, of Isohypsibius type, similar in size and shape on all legs (Fig. 4). Claws with enlarged and wide bulbous bases; generally, the external claws of first three pairs of legs and the posterior claw of the hind legs with larger bulbous bases (Fig. 4). Claw lunules absent. Primary branches of all claws with thin, short accessory points. Morphometric data of the holotype and eight paratypes are reported in Table 2. Remarks. Paratypes, body length from 188.8 µm to 345.7 µm. The eye spots and the orange colour of the body were visible in live specimens but not in all mounted specimens. Two exuviae were collected, which had eleven and twelve smooth eggs. Type repositories. Holotype and 20 paratypes. Holotype and nine paratypes deposited in the Laboratory of Zoology, Chetumal Institute of Technology, Quintana Roo, Mexico; 11 paratypes in the Bertolani collection, Department of Life Sciences, University of Modena and Reggio Emilia, Italy. Character ind 10 ind 2 ind 5 ind 8 ind 9 ind 1 ind 6 holotype ind 4 µm pt index Type locality: Urban zone of Chetumal, Quintana Roo, Mexico, Petcacab street intersection with Tres Garantias street (site S1: 18°30'13"N, 88°18'19"W; 9 m a.s.l.). The substrate was soil sediment with a very clay texture accumulated on the street between the sidewalk and the asphalt (site S 1 in Table 1). Other sites of collection. S2, Erick Paolo Martines street intersection with Colibri street; S3, Petcacab street intersection with Polyuc street; S4, Jesus Urueta street intersection with Heriberto Frias street (see Table 1). Etymology. The name ‘ chetumalensis ’ refers to the locality in which the new species was found. Differential diagnosis. Doryphoribius chetumalensis sp. nov. differs from all the other species of the genus in the distinctly enlarged and wide bulbous base to the claws (Fig. 4). The new species belongs to the zappaloi group (see: Michalczyk & Kaczmarek 2010), having no dorsal cuticular gibbosities and three macroplacoids. With reference to the other species within this group, D. chetumalensis sp. nov. differs, not only by the wide bulbous basal claws, but also in other characters. - Doryphoribius turkmenicus Biserov, 1999 was described as “white or slightly yellow” (Biserov 1999) and with a well-developed anterior band of large teeth, while the new species has distinctly orange body colour, and has no visible oral cavity armature; - Doryphoribius mexicanus Beasley et al., 2008, and Doryphoribius bertolanii Beasley & Pilato, 1987, were described with very simple oral cavity armature, composed of a single large round dorsal tooth placed in a posterior position (Beasley et al. 2008; Beasley & Pilato 1987), which is absent in D. chetumalensis sp. nov.; - Doryphoribius zappalai Pilato, 1971 has lunules in the claws which are absent in the new species; - Doryphoribius korganovae Biserov, 1994 was described as yellowish brown with smooth or slightly rugose cuticle (Biserov 1994), while D. chetumalensis sp. nov. has an orange colour and smooth cuticle; the claw bases of D. korganovae are expanded, but not as enlarged as the new species; - Doryphoribius qinlingense Li et al., 2004 was described as colourless, and with three macroplacoids increasing in length from first to third (Li et al. 2004), in the new species the three macroplacoids are of similar size; claw bases of D. qinlingense are expanded but not enlarged and bulbous, as in the new species; - Doryphoribius longistipes Bartels et al., 2008 was described as having no lunules or cuticular thickening (Bartels et al. 2008), making the swollen and bulbous bases of D. chetumalensis sp. nov. very distinctive in comparison; - Doryphoribius taiwanus Li & Li, 2008 was described as colourless and with a cuticular sculpture of dorsal and lateral tubercles (Li & Li 2008), which are absent in D. chetumalensis sp. nov.

The evelinae group: 4(2). Cuticular gibbosities present only on legs...................................................................5 -. Cuticular gibbosities present on dorsal side of the body........................................................6 5(4). Dorsal cuticle smooth.......................................................................... D. evelinae -. Dorsal cuticle with reticular design.................................................................. D. flavus 6(4). Cuticular gibbosities indistinct and irregularly arranged.......................................................7 -. Cuticular gibbosities distinct and arranged in defined transverse rows........................................... 8 7(6). Cuticular tubercles present, lunules absent, hind claws larger than claws I���III........................ D. maranguensis -. Cuticular tubercles absent, lunules present, hind claws slightly smaller than claws I���III..................... D. picoensis 8(6). Four dorsal gibbosities arranged in two caudal rows (configuration: II:2-2)....................... D. quadrituberculatus -. More than two rows of dorsal gibbosities.................................................................. 9 9(8) Three rows of dorsal gibbosities (III:4-2-2), oral cavity with six teeth in two bands....................... D. tessellatus -. More than three rows of dorsal gibbosities located throughout the dorsal cuticle...................................10 10(9). Seven rows of gibbosities with only two gibbosities in each row (VII:2-2-2-2-2-2-2)................. D. dupliglobulatus -. More than seven rows of gibbosities...................................................................... 11 11(10). Nine rows of gibbosities...............................................................................12 -. Ten rows of gibbosities (X: 2-3-1-3-1-3-1-2-2-2).................................................. D. mcinnesae 12(11). Six gibbosities in rows I and II, a single gibbosity on each of the hind legs, (IX:6-6-4-6-4-6-4-4-2+2[LIV])..... D. dawkinsi -. Less than six gibbosities (2 or 4) in row I, no gibbosities in the hind legs.........................................13 13(12). Two gibbosities in row I; gibbosity configuration IX: 2-4-4-4-4-6-4-4-2................................. D. barbarae -. More than two gibbosities in row I..................................................................... 14 14(13). Four gibbosities in row 2; gibbosity configuration IX:4-4-4-4-4-4-4-2-2.......................... D. huangguoshuensis -. Six gibbosities in row 2................................................................................ 15 15(14). Gibbosity configuration IX: 4-6-5-6-5-6-4-2-2..................................................... D. niedbalai -. Gibbosity configuration IX: 4-6-4-6-4-6-4-4-2..............................................................16 16(15). Main branches of both external and internal claws with uniform width and the distal portion tapering gradually........... ..................................................................................... D. maasaimarensis -. Proximal portion of the main branches of both external and internal claws more wide and tapered abruptly at about half length .......................................................................................... D. zyxiglobus, Published as part of P��rez-Pech, Wilbert Andr��s, Anguas-Escalante, Abril, Cutz-Pool, Leopoldo Querubin & Guidetti, Roberto, 2017, Doryphoribius chetumalensis sp. nov. (Eutardigrada: Isohypsibiidae) a new tardigrade species discovered in an unusual habitat of urban areas of Mexico, pp. 345-356 in Zootaxa 4344 (2) on page 353, DOI: 10.11646/zootaxa.4344.2.9, http://zenodo.org/record/1043140