Tardigrada of Grand Cayman, West Indies, with descriptions of two new species of eutardigrade, Doryphoribius tessellatus (Hypsibiidae) and Macrobiotus caymanensis (Macrobiotidae) Author Meyer, Harry A. text Zootaxa 2011 2812 28 40 journal article 10.5281/zenodo.205995 556343c6-a289-4d17-841e-ef4666ca7406 1175-5326 205995 Doryphoribius tessellatus sp. n. ( Figs. 2–11 ) Diagnosis. A Doryphoribius of the evelinae -group, with two macroplacoids, buccal cavity armature comprised of six large, round dorsal teeth in two rows, dorsolateral gibbosities in sequence III:4:2:2 and a cuticle covered by shallow depressions forming a reticular design. Material examined. Holotype , one paratype and one contracted juvenile specimen: sample 4c ( Table 1 ), Salina Reserve , East End District, Grand Cayman , Cayman Islands , West Indies, 1921ʹ0 0.3ʺ N and 8105ʹ48.7ʺ W, 9.1m asl, dry tropical forest, crustose lichen. FIGURE 2–3. Doryphoribius tessellatus sp. n. (2) Habitus, phase contrast microscopy. Scale bar: 100 μm. (3) Schematic pattern of gibbosities. FIGURES 4–7. Doryphoribius tessellatus sp. n. (4) Anterior gibbosities. (5) Posterior gibbosities. (6) Reticular design, middorsal region. (7) Reticular design, anterior region of the body. Scale bars: 4–6, 10 μm; 7, 5 μm. Description. Holotype—Body length 448.9 μm. Sex undetermined. Body yellow in live animal, eyes absent ( Fig. 2 ). Dorsal cuticle with 16 transverse undulations. Eight dorsolateral gibbosities in three rows, sequence III:4- 2-2 ( Fig. 3 ). Anterior row in second undulation with four low gibbosities in two partially fused pairs ( Fig. 4 ); two caudal rows, each with two prominent gibbosities ( Fig. 5 ). Dorsal cuticle, including undulations and gibbosities covered by shallow depressions forming a reticular design. Reticular mesh in caudal gibbosities and posterior ten undulations composed mostly of large depressions, 2.6–4.5 μm wide in gibbosities, 5.5–8.1 μm wide in undulations ( Fig. 6 ); in anterior gibbosities and anterior five undulations composed of large depressions (2.2–5.5 μm wide in gibbosities, 3.7–7.6 μm wide in undulations) intermixed with areas filled by very small depressions (<1.0 μm wide) ( Fig. 7 ). Ventral cuticle smooth. Buccopharyngeal apparatus of Doryphoribius type ( Fig. 8 ). Peribuccal lamellae and papulae absent. Buccal cavity armature composed of six large round teeth on dorsal wall in two rows of three ( Fig. 9 ). No other teeth visible with light microscopy. Mouth antero-ventral. Buccal tube 43.6 μm long and 4.7 μm wide [ 10.8 ], with anterior bend. Triangular pharyngeal apophyses present at end of buccal tube. Ventral lamina 24.3 μm [ 55. 7] long. Stylet supports inserted on buccal tube at 32.6 μm [ 74. 8]. Pharyngeal bulb oval with two macroplacoids decreasing in length. Microplacoid and septulum absent. First macroplacoid 8.7 μm [ 20.0 ] long with central constriction. Second macroplacoid 5.0 μm [ 11.5 ] long with subterminal constriction. Macroplacoid row 14.9 μm [ 34.2 ] long. Gibbosities and other cuticular thickenings absent on legs. Claws stout, of Isohypsibius - type , with small and smooth lunules ( Figs. 10–11 ). Claw lengths: external claw, leg I basal claw 8.8 μm [ 20.2 ], primary branch 15.1 μm [ 34.6 ], secondary branch 11.7 μm [ 26.8 ]; internal claw, leg I, bc 8.0 μm [ 18.3 ], pb 8.4 μm [ 19.3 ], sb 8.1 μm [ 18.6 ]; external claw, leg II bc 9.8 μm [ 22.5 ], pb 14.7 μm [ 33.7 ], sb 13.3 μm [ 30.5 ]; external claw, leg III bc 10.0 μm [ 22.9 ], pb 17.0 μm [ 39.0 ], sb 12.0 μm [ 27.5 ]. Orientation of other claws in holotype unsuitable for measurements. Paratype—Body length 358.7 μm. Buccal tube 41.0 μm long and 4.4 μm [ 10.7 ] wide. Ventral lamina 21.8 μm [ 53.2 ] long. Stylet supports inserted on buccal tube at 28.7 μm [70.0]. First macroplacoid 6.9 μm [ 16.8 ] long, second macroplacoid 4.9 μm [ 12.0 ] long. Macroplacoid row 12.8 μm [ 31.2 ] long. Claw lengths: Internal claw, leg II bc 6.8 μm [ 16.6 ], pb 11.0 μm [ 26.8 ], sb 8.2 μm [ 20.0 ]; internal claw, leg III bc 6.4 μm [ 15.6 ], pb 11.8 μm [ 28.8 ], sb 9.5 μm [ 23.2 ]; external claw, leg IV bc 4.3 μm [ 10.5 ], pb 12.3 μm [ 30.0 ], sb 7.2 μm [ 17.6 ]; internal claw, leg IV bc 6.1 μm [ 14.9 ], pb 14.4 μm [ 35.1 ], sb 10.0 μm [ 24.4 ]. Orientation of other claws unsuitable for measurements. Other characteristics as for holotype . FIGURES 8–11. Doryphoribius tessellatus sp. n. (8) Buccopharyngeal apparatus. (9) Buccal cavity armature, dorsal view. (10) Claw, leg I. (11) Claw, leg IV. Scale bars: 8, 20 μm; 9, 5 μm; 10–11, 10μm. Remarks. No eggs were found. On the contracted juvenile specimen the anterior row of gibbosities was more prominent than in the holotype and paratype . Etymology. The specific name tessellatus is a Latin masculine adjective referring to the mosaic pattern of the reticular design in the anterior cuticle. Type depository. The holotype and paratype ( SMLA 9400) are deposited in the W.A.K. Seale Museum, Department of Biology and Health Science, McNeese State University in Lake Charles, Louisiana, USA . Differential diagnosis. Michalczyk & Kaczmarek (2010) divide the species of Doryphoribius into four groups based on the number of macroplacoids and the presence or absence of cuticular gibbosities. Doryphoribius tessellatus sp. n. belongs to the evelinae -group, characterised by two macroplacoids and a cuticle with gibbosities. This group includes nine species: D. dawkinsi Michalczyk & Kaczmarek, 2010 , D. dupliglobulatus Ito, 1995 , D. evelinae ( Marcus, 1928 ) , D. flavus ( Iharos, 1966 ) , D. huangguoshuensis Wang, Wang & Li, 2007 , D. maranguensis Binda & Pilato 1995 , D. picoensis Fontoura, Pilato & Lisi, 2008 , D. quadrituberculatus Kaczmarek & Michalczyk, 2004 , and D. zyxiglobus ( Horning, Schuster & Grigarick, 1978 ) . Doryphoribius tessellatus sp. n. differs from D. evelinae and D. flavus in having dorsal gibbosities but lacking eyes and gibbosities on the legs; from D. dawkinsi , D. dupliglobulatus , D. huangguoshuensis and D. zyxiglobus in having fewer rows of gibbosities, and from D. maranguensis and D. picoensis in having four evident caudal gibbosities and a cuticle with a reticular mesh. In comparison to most species in the genus, Doryphoribius tessellatus sp. n. has relatively large macroplacoids and placoid row and a more posterior stylet support insertion point. While the new species shares with D. picoensis the character of having smaller Claw IV than Claws I–III, it most closely resembles D. quadrituberculatus . Both the new species and D quadrituberculatus have six large, dorsal teeth and similar caudal gibbosities. The two species can be distinguished by several independent characters: (1) the two species differ in gibbosity sequence (III:4- 2- 2 in Doryphoribius tessellatus sp. n . and II:2- 2 in D. quadrituberculatus ) (2) the anterior reticular design of the new species ( Fig. 7 ) differs from D. quadrituberculatus in consisting of large depressions interspersed with much smaller depressions ( Fig. 12 ) (3) the new species lacks five ventral teeth found in D. quadrituberculatus (4) the macroplacoids of D. tessellatus sp. n . , especially the second, are longer than those of D. quadrituberculatus (second macroplacoid pt 11.5 in the new species and 8.8 in D. quadrituberculatus in animals of comparable size) and (5) large eyes are present in D. quadrituberculatus but not in the new species.