Ramiellona tojolabala, Fragoso, Carlos & Rojas, Patricia, 2014

Fragoso, Carlos & Rojas, Patricia, 2014, New species and records of the earthworm genus Ramiellona (Annelida, Oligochaeta, Acanthodrilidae) from southern Mexico and Guatemala, Zootaxa 3753 (6), pp. 549-572 : 550-553

Ramiellona tojolabala sp. nov.

Figures 1 , 2

Localities and material. Mexico, Chiapas, National Park Lagunas de Montebello: (1) Type locality: 3.5 km after the entrance to the park, towards Tziscao. In the forests at right hand of the entrance to “Lago de Montebello”, 100 m away from the lake shore. Slightly disturbed pine-oak forest over a N-faced slope; within soil at 0–20 cm depth. 16°06’16”N, 91º42’13”W, 1490 m a.s.l.. 19J-23A-15CA (with 2, 9, and 4 posterior amputees, respectively), 11/19/ 1981, C. Fragoso and P. Lavelle. 6J-4A-3CA, 11/27/1997, C. Fragoso and J. Bueno. (2) 2 km after the entrance to the Park, towards Tziscao 300 m by a rural road. Ecotone cloud forest - pine oak forest with abundant bromeliads, within soil at 0–20 cm depth. 16°4’38”N, 91°43’10”W, 1540 m a.s.l., 8J-1A, 11/27/1997, C. Fragoso and J. Bueno. (3) km 6 on route to Tziscao, 4 km after “Cinco lagos”. Well preserved cloud forest and adjacent recently cleared forest, within soil at 0–20 cm depth. 16°7’2”N, 91°40’8”W, 1500 m a.s.l., 2A-4CA, 11/28/1997, C. Fragoso and J. Bueno.

Holotype. One clitellate adult collected 11/27/ 1997 in locality (1), IEOL 4238.

Paratypes. Five clitellate adults collected in locality (1), 11/19/1981: IEOL 2149, 2150, 2151, 2155, and in locality (3), IEOL 3336, dissected. Further 20 individuals, characterized only externally: localities (1), 11/19/1981: IEOL 2154, 3360, 4229, 4230, 4231, 4232, 4233, 4234, 4235, 4236, 4237; 11/27/1997: IEOL 4219, 4220, 4239, 4243; (2), IEOL 3320; (3), IEOL 4240, 4241, 4242, 4243.

Description. External. Length 50–120 mm (mean=78.9 mm, n=19; holotype 103 mm); width (postclitellar) 1.6–2.5 mm (mean=2.11, n=23; holotype 1.8 mm). Segments 128–239 (mean=189, n=14; holotype 213). Pigment absent. Prostomium prolobous, invaginated in the majority of individuals. Peristomium with several longitudinal annulations; in several individuals these grooves also present in the second segment. Secondary furrows: one postsetal in 7 and 8; in 9–13 one presetal and one postsetal; behind clitellum generally absent. Setae eight per segment, visible from segment 2, closely paired in the anterior region and quincuaxial in the posterior region. Setal formula in anterior region (average, n=5) (aa:ab:bc:cd:dd): 10: 2.9:1:7.3:0.6:34.9; 30: 4:1:4.2:1.2:39.1. In all individuals the first seta that shifts is seta c, then seta d and finally seta b; setae a never move and thus row A is recognized throughout. The quincuaxial arrangement occurs always in the second half of the body, after segment 100 (average beginning after 65% of segments, range 55–80%, n=12). Spermathecal setae present in some individuals (c. 50%), on one or both sides of 6 and 7 (one ind.), 7 (14 ind.) or 7 and 8 (one ind.), sometimes surrounded by swellings ( Fig. 1 A). Spermathecal setae slightly curved, without ornamentation, measuring 0.73– 0.93 mm, apex slightly arrow-shaped ( Fig. 2 C,D). Penial setae very conspicuous, robust, paired (a and b) in 17 and 19, semicircular ( Fig. 2 A); those of 17 always slightly smaller (length 0.93–1.12 mm, width 70 µm) than those of 19 (1.02–1.31 mm, 100 µm). Apex with a slight undulation, ending in an acute tip; ornamentation limited to undulation, consisting in several irregular rows of small, apex oriented thorns ( Fig. 2 B). Setae a and b of 18 visible.

Clitellum dark to light orange, dorsally in 13–19 (one ind.), 1/2 13 –19 (8 ind.), 14–19 (6 ind.) or 14 –1/2 20 (one ind.); ventrally in 13–19 (one ind.), 1/2 13 –19 (7 ind.), 14–19 (7 ind.) or 1/4 13 –1/4 20 (one ind.); saddle shaped in the region of the genital zone (17–19) and (in some individuals) in 15–16, reaching setae b; in some individuals fused with swellings of segments 14–16. Intersegmental furrows of clitellum recognizable in some individuals ( Fig. 1 A). Large dorsal pores present all along the body, first pore in 12/13 (n=20). Spermathecal pores paired in 7/8 and 8/9, very large, centered in AB ( Fig. 1 A), the posterior edge of each pore with iridescence. Due to their size, in some individuals the pores appear to be in segments 8 and 9, but when looking inside the pore the duct is clearly in the respective intersegment. Female pores in 14, presetal and slightly median to a, within an ovoidtriangular papilla extending in BB ( Fig. 1 A). Two pairs of prostatic pores in 17 and 19 just at the base of seta b, joined by square bracket-shaped seminal grooves, which run outside B ( Fig. 1 A). In some individuals the seminal groove is more bracket-like, whereas in others it curves slightly in 18 towards seta b. Male pores in 17/18, within the seminal groove, outside B; in fully clitellate individuals pores difficult to see. Genital marks unpaired ( Fig. 1 A) as mid-ventral, intersegmental papillae located in some intersegments of region 16/17–23/24; shape ovoidrectangular, extending into AA, BB or (more commonly) from outside B to outside B. Papillae in 20/21 and 21/22 mostly present (16 ind.). Holotype with papillae in 19/20–22/23. Papillae largest in 2nd or 3rd position, smallest generally in the last position. In some clitellate adults papillae of 17/18, 18/19 difficult to recognize, seeming more like swellings.

Internal. Septa 5/6 and 12/13 very thin and membranous; 11/12 slightly muscular; 6/7–10/11 muscular; septa 6/7–10/11 funnel-shaped and imbricated, those of 8/9–10/11 joined by 4–8 dorsal and lateral connective tissue fibers. One large gizzard in 5, extending up to 7–8. Extramural calciferous glands present in 7–12 (n=6), as dorsolateral sacs that open into the esophagus through a medium-sized conduct ( Fig. 1 C); internally each sac with large, numerous lamellae with free margins. Size of sacs: 7 ≤ 8 ≥ 9> 10> 11> 12. Intestine begins in 14/15 or 15/16. Intestinal typhlosole starting in 15 or 16, as a small fold increasing in size in 21, 22, lamina-shaped in 23 or 24 with free edge divided into three deep ridges (i.e. typhlosole trifid), continuing with same shape until abrupt end in 123, 124, 126. In 24–28 with up to 13 lateral folds, straight or slightly oblique in posterior direction. Smaller dorsolateral typhlosoles covering 6–7 segments in the region of 21–28, at both sides of main typhlosole. Intestinal caeca present as one or two paired dorsal pouches of the intestine in 21–24.

Single dorsal vessel visible throughout. Supra-esophageal vessel visible in 8–12. Lateral hearts in 7, 8, 9 and 10; latero-esophageal hearts in 11 and 12. Ventral vessel present. Extra parietal ventral vessels in each side of 13, 14, 15 and 16, running outside male gonoduct joined in 13 to paired infra-esophageal vessels, which run anteriorly until 7; vessels in 7 and 8 joined to lateral commissures before anastomosing with anterior septum and fusing with the ventral vessel. Paired clusters of tufted micronephridia along a longitudinal row in 2–4; septal meronephridia observed in the anterior face of septa 7/8–12/13 (four, two on each side). Parietal, closed meronephridia from 14 backwards; in some individuals four on each side (eight per segment) from 28–39; from 40 on only three nephridia observed on each side. Median ventral nephridium of last segments larger and with a small nephrostome into the preceding segment.

Holandric. Testes of 10 and 11 bushy and very large, joined to the male funnels by abundant coagulum and located mid-ventrally on the anterior septum. Male funnels iridescent and plicated, placed at both sides of the midventral line of the posterior septum; funnels of 11 larger than those of 10. Male gonoducts double, running along body wall in BC of 13–17, muscular in region 15–16, entering body wall in 17/18 just below the muscular duct of the prostate, towards mid-ventral line. Two pairs of seminal vesicles in 9 and 12, respectively fixed to septa 9/10 and 11/12; the anterior pair slightly smaller and in some individuals flat; the posterior pair larger and acinous. Two pairs of tubular prostates of similar size in 17 and 19, strongly coiled and fixed to intestine and septa by connective tissue, extending 1–4 segments backwards; muscular duct narrower and shorter (1/4) than glandular part. Penial setae a and b of both 17 and 19, in separate follicles that join to form an ovoidal muscle pouch; these pouches fixed by muscular stripes to lateral walls (one fiber) and to the floor (one or two fibers per pouch). Further retractor muscles in 16/17 and 18/19, extending from mid-ventral line to dorso-lateral walls; mid-ventral floor in segments 16–18 thicker. In each follicle, one undeveloped extra seta present.

Ovaries one pair, large, on the floor of 13, with bushy coral shape and numerous eggs not in rows; female funnels one pair in 13, at both sides of mid-ventral line. Two pairs of similar-sized spermathecae discharging in 7/8 and 8/9, ampulla and duct in the respective posterior segment, diverticulum in the anterior one; diverticulum sessile, discoidal, tightened to the parietes and with the overall appearance of a cabbage; duct wider and shorter than the elongated ampulla, which narrows in the middle part ( Fig. 1 B). Length of spermathecae 2 mm. Spermathecal setae embedded in ovoidal pouches of muscular tissue fixed to lateral parietes by muscular stripes. Two follicles within pouches, no extra setae observed.

Etymology. The name of the species is dedicated to the Tojolabal people who inhabit the region of Montebello lakes and other nearby zones, in the highlands of the state of Chiapas.

Remarks. R. tojolabala belongs to the group of species with last hearts in 12 and quincuaxial setae. Being holandric it is separated from the metandric R. guatemalana , R. balantina , R. tecumumami , R. americana , R. lavellei and R. vulcanica ; by having two pairs of seminal vesicles it is separated from R. irpex (one pair), although both species share the dorsal calciferous glands in segments 7–11. The quincuaxial arrangement of setae separates it from the other holandric species of the genus like R. sauerlandti , R. stadelmanni , R. strigosa , R, eiseni and R. microscolecina , sharing with the last three species the shape of spermathecae. From the quincuaxial R. lasiura it is also separated because, after the revision of one paratype (see further on), this last species turned out to be metandric as was assumed by Gates (1962). This species has previously been referred to as " Ramiellona sp. nov. 28" ( Fragoso 1993), " Ramiellona sp. nov. 13" ( Fragoso 2001), and " Ramiellona sp. nov. 14" (Fragoso 2007; Fragoso & Brown 2007).

Figures

FIGURE 1. Ramiellona tojolabala sp. nov. A. External ventral view of anterior region. B. Spermatheca from segment 9, dorsal view. C. Transverse section (hand made dissection) from segment 9, showing the esophagus and dorsal stalked calciferous glands. D = dorsal, V = Ventral. Holotype IEOL 4238. Scale 1 mm.

FIGURE 2. Ramiellona tojolabala sp. nov. A. Penial seta a of segment 19 (scale 200 µm). SEM photographs. B. Apex of penial seta 19 a (scale 50 µm). C. Spermathecal seta a of segment 7 (scale 100 µm). D. Apex of spermathecal seta 7 a (scale 20 µm). Paratype IEOL 2149.