Pergalumna dactylaris, Palacios-Vargas, José G. & Villagomez, Fernando, 2017

Palacios-Vargas, José G. & Villagomez, Fernando, 2017, Three new species of Pergalumna (Acari: Oribatida: Galumnidae) from the tropical rainforest of Veracruz, Mexico, Zootaxa 4242 (1), pp. 77-94 : 88-91

Pergalumna dactylaris sp. nov.

( Figs. 41 –60)

Diagnosis. Bothridial setae setiform, apically barbed; integument densely striated in most of the body, generally with vertical orientation, some striations can be horizontals joining two vertical lines; A2 absent; notogaster with ten pairs of alveoli; dorsosejugal suture fully developed; lyrifissure iad situated near anal plate; without porose area postanalis and medial pore.

Description. (N=10) Length of males 867–936 (916), width 709–769 (740); length of females 818–966 (877), width 719–789 (750), height of both sexes 734. Color black to dark brown, with a light lenticular yellow region in prodorsum basis and anterior part of notogaster.

Prodorsum ( Figs. 41 , 43, 44, 56). Slightly granulated surface in anterior region, near dorsosejugal suture this ornamentation disappears and begins an irregular striation; dorsosejugal suture separates a very large bright yellow lenticular region and continues towards anterior part of notogaster; lines L and S present, sclerotized; Ad apparently absent. Prodorsal setae ( Fig. 45 ) present, in short, smooth and setiform (32), le long and barbed (114), ro similar in size to le, but a little smaller (98), inserted on the edge of ventral plate, barbed. With a cuticular depression anterior to insertion of le, rostrum with blunt apex.

Bothridial setae ( Figs. 45 , 60) setiform, long and thin (126), barbed apically, no “S” form insertion in bothridium. Chelicera (Fig. 46) normal shape (L=290, W=109), ornamented with punctuations from anterior to middle region, cha (81) and chb (52) barbed.

Notogaster ( Figs. 41 , 54 ). Integument completely striated (Fig. 59), ten pairs of alveoli, lx present; porose area A2 absent, all others similar in size and form; without medial pore.

Porose area Aa (L=32, W=20) and A1 (L=37, W=17) oval to round, A3 (L=20, W=17) oval. Notogastric lyrifissures and setae in the same position as Pergalumna hypergranulosa sp. nov. except lyrifissures ih and ips located laterally anterior to A1, opisthosomal glands (gla) well developed and slightly protuberant.

Pteromorph bilobed (Figs. 49, 57) (L=425, W=205 with convex anterior region, 220 in middle and 235 in distal), integument granulated, striated with ornamentation from basis to center, with additional irregular and linear sclerotized ornamentations, with a central notch; lyrifissure ia thick below the notch; c in habitual position.

Ventral plate (Figs. 42, 55). Integument densely striated on whole plate. Subcapitulum (Fig. 47) (L=164, W=178) slightly granulated and ornamented, h long (25); epimeral setae of two sizes, 1b (17) short, 3a, 4a and 3b (27) longer; aggenital setae short (20), three pairs of adanal setae short (15) with ad3 slightly separated; lyrifissure iad near anal plate; porose area postanalis absent (Fig. 48); genital plates (L=115, W=121) slightly striated, with four faint longitudinal lines (Fig. 58), with six short genital setae (15) inserted in 2–4; anal plates (L=164, W=175) completely striated, with two pairs of short anal setae (15).

Lateral region (Figs. 44, 57). Lamellar (L) and sublamellar (S) lines present and well sclerotized, arched and parallel, sublamellar line S irregular; circumpedal line thick and sclerotized, slightly protuberant; rostrum with blunt apex.

Legs. All heterotridactylous. Leg setation and solenidia from leg I–IV (solenidium in parenthesis). Femora 4- 4-2-2; genua 3(1)-3(1)-1(1)-2; tibiae 4(2)-4(1)-3(1)-3(1); tarsi 20(2)-15(2)-15-12.

Leg I ( Fig. 50 ). Femora L=77, W=30; genua L=38, W=13; tibiae L=87, W=52; tarsi L=159, W=37. Solenidium σ (155) anterior, dorsal; solenidium φ1 (242) very long, φ2 (81) posterior, both dorsally inserted, ω1 (77) shorter than ω2 (112); famulus å very short (5), with blunt apex, ft´´setae is situated posteriorly. Leg II (Fig. 51). Femora L=193, W=84; genua L=74, W=32; tibiae L=81, W=44; tarsi L=114, W=37. Solenidium σ (163) dorsal and distal, φ (176) dorsal. ω1 and ω2 identical (54), blunt apex, ft´ anterior to ω1. Leg III ( Fig. 52 ). Femora L=133, W=91; genua L=37, W=27, tibiae L=121, W=42; tarsi L=136, W=35. Solenidium σ (57) rigid, φ (151) dorsal, at the height of l´. Leg IV (Fig. 53). Femora L=172, W=84; genua L=74, W=25, tibiae L=131, W=37; tarsi L=160, W=30. Solenidium φ (131) in middle region of the tibia, without cuticular fold.

Type material. Holotype (male) mounted on slide. 08/IV/2014, Mexico, Veracruz, Estación de Biología Tropical , Los Tuxtlas, sample of soil and litter, L. Villagomez, L. A. Martínez y A. D. Ruiz cols. 18°35’02.04’’ N, 95°04’39.54’’ W. 242 m a.s.l. Four paratypes on slide with same data except 18/IV/2014 (1♀ and 3♂), four paratypes on slide with date 09/VI/2014. F. Villagomez col. (1♀ and 3♂) . Fifteen more paratypes from the same locality and same data deposited in 96% ethanol. This material is deposited in the collection of Collembola de México y Ácaros Edáficos of Laboratorio de Ecología y Sistemática de Microartrópodos ( LESM), Facultad de Ciencias , UNAM.

Etymology. The specific name “ dactylaris ” describes the similarity of the integumentary ornamentation with human fingerprints.

Remarks. The ornamentation on the prodorsum and notogaster of P. dactylaris sp. nov. resembles Pergalumna striata ( Pérez-Íñigo & Baggio, 1980) , from Brazil, but can be distinguished by the presence of only three notogastric porosea areas instead of four, and being almost twice as long as in P. striata (400–440). The shape of bothridial setae bs is similar to Pergalumna decorata Balogh & Mahunka, 1977 ( Bolivia) , which has Aa closer to lm than la, whereas in P. dactylaris sp. nov. Aa is located exactly in the middle between them; besides interlamellar setae in are short, but not minute, and the Bolivian species is much smaller (L=637–653, W=469– 494) than the Mexican (L=838–986, W=720–789). New species is also similar to Pergalumna decoratissima Pérez-Íñigo & Baggio, 1986 ( Ecuador) which has a granulated prodorsum and the rest of the body ornamented with longitudinal striae or grooves, however, lamellar setae (le) in this species is more than twice as long as rostral setae (ro), and the anal and genital plates are ornamented in the same manner, while in P. dactylaris sp. nov. prodorsal setae le and ro are subequal in size, also genital and anal plates are ornamented with different patterns, with less ornamentations on genital plate. Finally Pergalumna paradecoratissima Ermilov & Kalúz, 2012 ( Ecuador) differs by having a tooth-shaped projection on each side of prodorsum, anal plate smooth and the presence of one small and oval porose area postanalis. In addition, P. dactylaris sp. nov. seems to be the only species with a clear and well delimitated lenticular region between prodorsum and the base of notogaster.

Sympatric speciation. The three species come from Los Tuxtlas, Veracruz, and as they live in the same locality and biotope, it seems that a sympatric speciation has occurred. We have analyzed the chelicerae, but we have not found any important difference, but we think that each of them is using a new niche, which had reduced gene flow with individuals exploiting another niche. Unpublished data support this, Villagomez (2015) performed techniques of extraction and amplification of ribosomal 18S rRNA and mitochondrial Cytochrome Oxidase c 1 (Cox 1) for molecular characterization of these species and to delimit the relationship between genetic distance and morphological characters. The results show that genetic distance between species with molecular marker Cox 1 observed in the three species varies from 0.3, 2.46 or 6.02%.

Figures

FIGURES 41 ‾ 44. Pergalumna dactylaris sp. nov. 41. Notogaster, dorsal view; 42. Ventral plate; 43. Prodorsum; 44. Lateral region, pteromorph and legs ommited. Scale bars 50 µm.

FIGURES 45 ‾ 49. Pergalumna dactylaris sp. nov. 45. Prodorsal setae; 46. Right chelicera, paraxial view; 47. Subcapitulum, ventral view; 48. Posterior region; 49. Right pteromorph. Scale bars 50 µm.

FIGURES 50 ‾ 51. Pergalumna dactylaris sp. nov. 50. Right leg I of holotype, antiaxial view; 51. Right leg II of holotype, antiaxial view. Scale bars 20 µm.

FIGURES 52 ‾ 53. Pergalumna dactilaris sp. nov. 52. Left leg III of holotype, paraxial view; 53. Left leg IV of holotype, paraxial view. Scale bars 20 µm.

FIGURES 54 ‾ 60. SEM images of Pergalumna dactylaris sp. nov. 54. Notogaster and prodorsum, dorsal view; 55. Ventral plate and subcapitulum, ventral view; 56. Rostrum, frontal view; 57. Prodorsum, lateral view; 58. Genital plates, showing ornamentation; 59. Cerotegument ornamentation; 60. Bothridial setae bs. Arrows indicate integument ornamentation.