Doryphoribius dawkinsi, Michalczyk, Łukasz & Kaczmarek, Łukasz, 2010

Michalczyk, Łukasz & Kaczmarek, Łukasz, 2010, Description of Doryphoribius dawkinsi, a new species of Tardigrada (Eutardigrada: Hypsibiidae) from the Costa Rican highlands, with the key to the genus Doryphoribius, Zootaxa 2393, pp. 46-58 : 50-52

Doryphoribius dawkinsi sp. nov.

FIGURES 3–26 , TABLE 2

Material examined: Holotype and 16 paratypes: Central America, Costa Rica: Cartago Province, Heredia, 84.11289°W and 10.00285°N, 1161 m asl, urban area, moss from tree, 1 specimen; Guanacaste Province, in the vicinity of Cenzosa Vista al Mar, the “Bosque Nacional Diria” forest, 85.63004°W and 10.12553°N, 960 m asl, premontane wet forest, liverworts from tree, 13 specimens; Puntarenas Province, San Vito, in the vicinity of the cemetery, 82.97075°W and 8.81742°N, 1020 m asl, urban area, liverworts from tree, 2 specimens; San Jose Province, Chirripo National Park, 83.60058°W and 9.46502°N, 1288 m asl, premontane wet forest, moss from stone, 1 specimen. All collected by the second author in December 2002.

Description (see Table 2 for measurements, pt values and basic statistics): Body yellow ( Figs. 3–9 ). Eyes absent in all examined specimens. Dorso-lateral cuticle covered with small (0.5–1.5 in diameter), irregular, often elongated tubercles (Figs. 10, 13–14, 16–18). Apart from evenly scattered tubercles, nine rows of gibbosities cover dorso-lateral parts of the body. Additionally, there is also a single gibbosity on each of the hind legs (Fig. 18). The gibbosity configuration is as follows: IX:6-6-4-6-4-6-4-4-2+2[L IV] ( Figs. 3–4 , 6–9 ). Each of the most lateral gibbosities in rows I, VII and VIII is placed slightly posteriorly relative to the dorsal ones (i.e., gibbosities I c, VII b and VIII b) ( Figs. 8–9 , 12). Gibbosity rows II, IV and VI are in line with legs I, II and III, respectively. Gibbosities in row I are slightly smaller than all other gibbosities. Both the cuticular sculpture and gibbosities exhibit significant variation in their appearance. Namely, in some individuals cuticular tubercles are scattered and weakly visible (Fig. 15), whereas in others they are distinct and densely arranged (Fig. 13). Locally, elongated tubercles may merge and form a quasi-reticulum (Figs. 16–17). Also, in some animals gibbosities are clearly defined and easy to count ( Figs. 3–6, 8 ), whereas in others they are only weakly outlined and may be difficult to identify, especially under LM ( Figs. 7, 9 ). Legs I–III without gibbosities. Ventral cuticle smooth (i.e., without tubercles and gibbosities).

On the dorsal side of the head there is a small round or triangular tubercle (ca. 2.0 in diameter) (Figs. 11– 12, see also Remarks). This structure is visible only in SEM.

Mouth antero-ventral. Bucco-pharyngeal apparatus of the Doryphoribius type ( Figs. 19–22 ). Peribuccal lamellae and papulae absent. Oral cavity armature visible only in SEM ( Figs. 19–20 ), consisting of a single band of very small (ca. 0.1 in diameter), cone shaped teeth arranged in ca. 5 rows placed on the ring fold in the centre of the oral cavity. Buccal tube with a single anterior bend (visible in lateral view only) and with a ventral lamina ( Fig. 21 ). At the end of the buccal tube rounded pharyngeal apophyses present. Pharyngeal bulb spherical with two macroplacoids decreasing in length (i.e., configuration 2-1) ( Fig. 22 ). The first macroplacoid in the shape of a short rod, with a slight central constriction. The second macroplacoid granular, without constrictions. Microplacoid and septulum absent.

Claws of the Isohypsibius type, similar in shape on all legs, with short basal claws ( Figs. 23–25 ). Lunules absent, but claw bases may be occasionally slightly widened. Internal claws I–III and anterior claws IV smaller than external claws I–III and posterior claws IV, respectively. However, the difference between the claws is smaller on hind legs than on legs I–III. Claws I–III similar in size and all smaller than claws IV. Primary branches of claws with thin, but well visible accessory points ending at the highest point of the primary branch. Bars and other cuticular thickenings on legs absent.

Eggs unknown (see also Remarks).

Remarks: Given that the head tubercle observed in SEM (Figs. 11–12) is in a location that corresponds with the base of the median cirrus in marine heterotardigrades (e.g., Stygarctus), it could be a homologous sensory organ. Interestingly, conspicuous cuticular structures in the same location were described also in other eutardigrades (e.g., cuticular depression in Macrobiotus derkai reported by Degma et al. 2008).

Although eggs are unknown, we should probably expect them to be smooth and deposited in exuvium as in all other known Doryphoribius species.

Locus typicus: Guanacaste Province, in the vicinity of Cenzosa Vista al Mar, the “Bosque Nacional Diria” forest, 85.63004°W and 10.12553°N, 960 m asl, Premontane wet forest, liverworts from tree.

Etymology: We take great pleasure in dedicating the new species to a distinguished scientist, Professor Richard Dawkins (Oxford University, UK), and by this we thank him for his input in evolutionary biology as well as for his tireless popularisation of science, rationalism, scepticism and critical thinking and all actions against pseudoscience, religion and other sorts of superstition.

CHARACTER N RANGE MEAN SD Holotype Type depositories: Holotype and five paratypes on one slide (no. CR935/1) and other four paratypes (slides no. CR28n/2, CR253/2, and CR168/4) mounted in Hoyer’s medium are preserved at the Department of Animal Taxonomy and Ecology, A. Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland.

Figures

FIGURES 3 – 5. Doryphoribius dawkinsi sp. nov. — habitus in LM: 3 — dorso-lateral view; 4 — lateral mid section; 5 — ventro-lateral view. Roman numbers on 3 - 4 indicate transverse rows of cuticular gibbosities. Scale on 4 - 5 same as on 3. 3 and 5 — holotype, 4 — paratype. All PCM.

FIGURES 6 – 9. Doryphoribius dawkinsi sp. nov. — habitus in SEM: 6 – 7 — dorsal view; 8 – 9 — lateral view. 6 and 8 — an individual with evident cuticular gibbosities; 7 and 9 — specimens with weakly outlined gibbosities. Roman numbers indicate transverse rows of cuticular gibbosities.

FIGURES 19 – 22. Doryphoribius dawkinsi sp. nov. — oral cavity and buccal apparatus: 19 – 20 — oral cavity armature consisting of a single band of teeth placed on the ring fold; 21 — buccal apparatus (lateral view, note the anterior bend of the buccal tube); 22 — macroplacoids. 19 – 20 — SEM, 21 – 22 — PCM.

FIGURES 23 – 26. 23 – 25 — Doryphoribius dawkinsi sp. nov. — claws: 23 – 24 — claws II; 25 — claws IV; 26 — Doryphoribius zyxiglobus (specimen from China, slide by C. W. Beasley, no. Yunnan Bai Shui 7 - 11 - 96, C- 47) — claws II with lunules. 23 — SEM, 24 – 26 — PCM.