Atatina arimikuritea, Hernández-García & Rodríguez & James & Limeira-De-Oliveira & Rousseau, 2024

Hernández-García, Luis Manuel, Rodríguez, Giovanny Angiolillo, James, Samuel Wooster, Limeira-De-Oliveira, Francisco & Rousseau, Guillaume Xavier, 2024, Two new species of Atatina earthworm (Rhinodrilidae, Clitellata) from the Gurupi Biological Reserve, Maranhão, Brazil, Zootaxa 5514 (5), pp. 494-500 : 496-498

Atatina arimikuritea , sp. nov. Hernández-García ( Figs 2A–G )

Holotype: LB00007 , adult, complete, collected in epiphytic soil, Old-growth Forest , Gurupi Biological Reserve, Centro Novo do Maranhão , Maranhão, Brazil, 3°37'37.35"S, 46°48'32.44"W, 128 masl, 24 May 2023, Hernández-García, L.M & Rousseau, G.X. colls.

Paratype: LB00008 , LB00009 , two adults, one complete and one amputee, respectively, both collected in epiphytic soil, same locality as holotype. LB000010 , adult, complete, collected in soil, Burned Forest , Gurupi Biological Reserve, Centro Novo do Maranhão , Maranhão, Brazil, 3°32'31.99"S, 46°47'43.93"W, 128 masl, 29 March 2022, Hernández-García, L.M & Rousseau, G.X. colls .

Etymology: The species name came from the Awa Guajá indigenous language for this species meaning “true” (tea) “earthworm” (arimirikuri).

Description. Dimensions: holotype 18 mm in length by 1.8 mm at X, 2.0 mm at clitellum, 1.8 mm at XXX, 84 segments; complete paratypes 27–36 mm in length by 1.48–1.58 mm at X, 1.84–1.96 mm at clitellum and 1.73–1.74 mm at XXX, 120–135 segments. Body cylindrical, beige after fixed. Setae ab and cd commence on II, closely paired-type. Setal arrangement aa:ab:bc:cd:dd = 1.5:1.0:2.0:0.5:5.5 at XXX. Prostomium prolobic, invaginated. Clitellum annular in XIII–XXII. Genital markings absent ( Fig. 2A,B ). Tubercula pubertatis as puberal furrows in 2/3 XVIII–1/3 XX next to C line ( Fig. 2B ). Post-clitellar common setae sigmoidal, 0.123 –0.136 μm, smooth at the apical part ( Fig. 2C ). Intraclitellar genital setae at AB line truncated, the unique seta recovered 192 μm in length, straight, and smooth at the apical part ( Fig. 2D ). Microscopical male and female pores not recognized externally. Spermathecae pores and associated marks not recognized. Nephropores visible from V in CD line.

Septa 6 /7–14/15 membranous. Gizzard in segment VI, highly muscular, occupying four segments. Intestinal origin in XVI. Beginning of typhlosole as simple folds at XVII. Gradually decreases in size and disappear after LVIII. Three pairs of intramural calciferous glands are present in X–XII, vertical lamellae open to esophagus lumen ( Fig. 2E ). Holonephric, the nephrostome in postclitellar nephridia is connected to a tube (first loop), as long as the bladder. A second loop, same length, connect to the bladder ( Fig. 2F ). Three pairs of fine blood vessels are laterally in VII–IX, all connected to dorsal and ventral vessels. Two pairs of lateroesophageal hearts, kidney shaped, in X–XI. Supra-esophageal vessel runs over the dorsal side of the intestine.

Ovaries in XIII. A pair of female funnels are in 13/14; female pores open in 14/ 15 in A line. One pair of spermathecae in IX; Seminal chambers absent, the duct of spermathecae measures 77–80 μm wide and 100–120 μm in length, the saccular ampulla measures 85–94 μm wide and 200–230 μm in length, spermathecae open posteriorly to the segment and laterally in CD line ( Fig. 2G ). One pair of testicles and male funnels are located ventrally, enclosed in testes sacs in XI. A pair of long seminal vesicles are in XII extended laterally to LXX. A pair of intraparietal, and iridescent deferent ducts, go parallel through C line and open on 17/18.

Remarks. The new species Atatina arimikuritea sp. nov. is similar to A. puba Righi 1971 and A. gatesi Righi and Ayres 1978 by the presence of one pair of spermathecae and the prolobic prostomium. The main similarity found with Atatina arimikuriaka sp. nov. is the type and extension of the clitellum. Differences with A. puba and A. gatesi include the clitellum type (annular vs saddle-shaped) and extension (XIII–XXII vs XIV–XXIII or XIV–XXI), and position of first calciferous glands (X vs IX or XI). Difference with Atatina arimikuriaka sp. nov. includes the number of spermathecae (1 vs 3), the prostomium type (prolobic vs tentacular) and size ( Atatina arimikuritea sp. nov. is a half of size). More details for comparison between species are in table 1.

Figures

FIGURE 2. Atatina arimikuritea sp. nov. A. Lateral view of anterior region showing the clitellum. B. Ventral view of clitellum region after dissection. C. Left common a seta of XXXV. D. Right genital a seta of XVIII. E. Dorsal view in cross-section of the left calciferous gland of X–XII. F. Left post-clitellar nephridia of XXX. G. Dorsal view of left spermathecae of IX. amp: ampulla. bd: bladder. c: crop. d: duct. dv: dorsal blood vessel. Gz: gizzard. h: lateroesophageal heart. I: intestine. lam: lamella. lbv: lateral blood vessel. lu: intestinal lumen. nep: nephridia. np: nephropore. sv: seminal vesicle. TP: tubercula pubertatis.