Crenubiotus, Lisi & Londoño & Quiroga, 2020

Lisi, Oscar, Londoño, Rosana & Quiroga, Sigmer, 2020, Description of a new genus and species (Eutardigrada: Richtersiidae) from Colombia, with comments on the family Richtersiidae, Zootaxa 4822 (4), pp. 531-550 : 534-538

Crenubiotus gen. nov.

( Figs 1–3 , Tables 2–3)

Material examined: The neotype, 4 neoparatypes and three eggs of M. crenulatus , deposited in the Pilato and Binda collection (slide Nos. 2284 and 2285) at the University of Catania. Type locality: Valtellina ( Northern Italy), Palabione , 1700 m asl (these are the only data available from Binda 1974). 65 specimens deposited in the Centro de Colecciones Científicas de la Universidad del Magdalena: CBUMAG:TAR:00067 (4 specimens), 00069 (1 specimen), 00073 (10 specimens), 00074 (2 specimens), 00075 (1 specimen), 00076 (1 specimen), 00092 (10 specimens), 00093 (10 specimens), 00094 (13 specimens), 00096 (12 specimens), and 00403 (1 egg). Localities : San Lorenzo 11°06’20.0’’N, 74°03’50.0’’W, 2284 m asl, and Bella Vista 11°05’47.8’’N, 74°05’04.4’’W, 1930 m asl. Complete information with correspondence between localities, sample types and slide numbers, is given in Table 1.

Diagnosis: Genus of the family Richtersiidae , with evident cuticular pores present in all life stages, flat cuticular tubercles/granules form a dorso-caudal band, and smaller tubercles/granules are present on all the legs. Buccopharyngeal apparatus of a modified ‘ Macrobiotus type’, i.e. with ten peribuccal lamellae, a rigid buccal tube with the ventral lamina, which is provided with an additional ventral thickening in its anterior portion, appearing as an additional ridge laterally and as an elongated trapezoidal structure pointing forward ventrally; dorsal apophysis absent or very reduced into a small thickening. Oral cavity armature seemingly without anterior and posterior bands of teeth (not visible, at least in light microscopy), but provided of the crest system, with only the lateral crests (medial lacking) both dorsally and ventrally; the latero-dorsal crests form each a rounded thickening in the medial extremities. Two macroplacoids and a microplacoid in the pharynx. Big stylet furcae with the thickened, swollen apices of the branches very developed and elongated laterally.

Symmetric, doubled claw Y-shaped, with very long stalk system, proximally forming a proper laminar peduncle while distally it has a round section, separated by a septum from a subsequent intermediate tract; from this, an incomplete septum, closing only the main branch base, leads to a following common tract of the two branches where their suture is visible; claw branches diverging quite high in the whole claw height and forming a nearly acute angle.

Very big lunules on all legs, indented in a very regular pattern by long, narrow teeth in the known species.

Egg, in the known species, non-areolated, with very finely and delicately reticulated conical processes, which are conformed by a main basal body, a more slender distal portion ending in a terminal, flexible filament; process base with projections on the egg shell.

Type species: Crenubiotus crenulatus ( Richters, 1904a) comb. nov.

Etymology: The name of the genus refers to the specific epithet of the nominal species (Crenu -) combined with the generic name of Macrobiotus (- biotus).

Composition: Crenubiotus crenulatus comb. nov., Crenubiotus revelator sp. nov.

Figures

FIGURE 1. Buccal tube of Crenubiotus gen. nov. and Mesobiotus sp. A. Lateral view of the buccal tube showing the detail of the buccal tube apophyses in a paratype of Crenubiotus revelator sp. nov. (slide CBUMAG:TAR: 00067). Arrow “a” points to the ventral apophysis and the arrow “b” to the putative dorsal residual apophysis. B. Detail of the buccal tube apophyses in a neoparatype of Crenubiotus crenulatus comb. nov. (slide No. 2284 from Pilato and Binda collection); arrows same as in A. C. Ventral view showing the trapezoidal appearance of the ventral thickening (arrow, pointing at the caudal base of the “trapeze”) in Crenubiotus revelator sp. nov. (slide CBUMAG:TAR: 00096). D. Ventral view of the typical arrow-shaped ventral lamina (arrow) in a Mesobiotus sp. E. Detail of the stylet furca in Crenubiotus revelator sp. nov., the arrow indicates a lateral process of the furca (slide CBUMAG:TAR: 00067). Scale bars 10 µm.

FIGURE 2. Claw structure in Crenubiotus gen. nov. (from the holotype of C. revelator sp. nov., slide No. CBUMAG: TAR:00092-1). Arrow “a”: basal portion of the stalk system in the shape of a laminar peduncle; arrow “b”: distal, enlarged, portion of the stalk system; arrow “c”: intermediate portion of the claw without suture; arrow “d”: complete septum; arrow “e”: incomplete septum; arrow “f”: distal portion of the common portion with the suture between the claw branches.

FIGURE 3. Claws of Crenubiotus gen. nov. A. Claws of legs I of a paratype of Crenubiotus revelator sp. nov., arrows “d” indicate the complete septum between stalk and common portion of the claw in different views; slide CBUMAG:TAR: 00094. B. Claws of legs II of the holotype of Crenubiotus revelator sp. nov., arrow “d” indicates again the complete septum, “a” the basal peduncle. C. Claws of legs IV of a neoparatype of Crenubiotus crenulatus comb. nov., arrow “a” indicates the shape of the stalk system in frontal view; “f” indicates the suture between the two branches, “g” the claw base continuing into the lunule margin; slide No. 2284 from Pilato and Binda collection. Scale bars 10 µm. The letters of the various arrows are not in alphabetic order but follows the same denomination of Fig. 2 for easier comparison.