Pergalumna obsidiana, 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 : 81-88

Pergalumna obsidiana sp. nov.

( Figs. 22 –40)

Diagnosis. Bothridial setae setiform with unilateral barbulations, integument densely granulated throughout the body, reflective, giving a shiny black appearance. All prodorsal seta present; porose area A2 absent; notogaster with ten pairs of alveoli; dorsosejugal suture interrupted; lyrifissure iad situated near anal plate; without medial pore and porose area postanalis.

Description. (N=7) Length of males 443–473 (463), width 335–374 (354); length of females 473–513, width 335–374, height 360–371 of both sexes (364). Color shiny black, a clear coppery lenticular area present.

Prodorsum ( Figs. 22 , 24, 36). Surface strongly granulated and warty; lamellar (L) and sublamellar (S) present, arched and parallel, sclerotized; Ad present, small and oval (L=12, W=7); all prodorsal setae (Figs. 25, 36) setiform and barbed. Interlamellar setae (in) long (110) rigid aspect, lamellar setae (le) flexible (88), rostral setae (ro) near the ventral surface (56).

Bothridial setae (Figs. 25, 40) setiform, longer than other prodorsal setae (122), barbed unilaterally, barbulations extending from base to apex, in middle area the most developed barbulations, decreasing to terminal region, without “S” insertion. Chelicera normal (Fig. 28) (L=167, W=62), middle region ornamented with punctuations; cheliceral setae cha (42) and chb (25) barbed.

Notogaster ( Figs. 22 , 34 ). Completely granulated, looking like small warts (Fig. 29); integument punctuated below warts in the anterior region surrounding lm; notogastric setae reduced to alveoli, habitual position of alveoli and lyrifissures in the group. Pore lx between la and lm.

Porose area ( Fig. 22 ) Aa (L=25, W=10) elongated and oval, horizontal; A1 (L=27, W=10) slightly larger than Aa and diagonal; A3 (L=12, W=10) smaller and semicircular.

Pteromorph bilobed (Figs. 27, 36) (L=230, W= 180 in proximal region, 160 in middle and 200 in distal), integument warty at the edges; central zone of integument dotted; central notch present, heavily sclerotized, ia and c in habitual position.

Ventral plate (Figs. 23, 35). Integument punctuated, cerotegument densely granulated across the plate. Subcapitulum ( Fig. 26 ) (L=96, W=101) punctuated with weakly ornamented, bilobed apex; setae h short (11); epimeral setae 1b, 3a, 4a and 3b (13) present; aggenital setae short (8), three pairs of adanal setae (12) near anal plate; lyrifissure iad in the margin of the plate; without porose area postanalis; genital plates (L=71, W=70) smooth with six short genital setae (8) inserted in 2–4, with four to five conspicuous protuberances between genital setae, more evident in lateral view (Figs. 23, 24, 38); anal plates (L=74, W=103) completely granulated, with two pairs of short anal setae (8).

Lateral region (Figs. 24, 37). Lamellar (L) and sublamellar (S) lines present, sclerotized, arched and parallel; interlamellar setae (in) inserted close to line L, circumpedal line thick and sclerotized; rostral region with cuticular sclerotized projection, smooth and directed forward, rostrum apex curved inwards.

Legs. All legs with basal granulation in femora, 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. 30). Femora L=103, W=49; genua L=47, W=20; tibiae L=61, W=34; tarsi L=98, W=24. Solenidium σ (126) dorsal, φ1 (133), very large and medial, φ2 (71) preapical, both inserted dorsally. ω1 (57) anterior to all tarsal setae, ω 2 (70) posterior to ft´´. Famulus (7) very short, blunt apex. Leg II ( Fig. 31 ). Femora L=106, W=32; genua L=27, W=17; tibiae W=49, A=24; tarsi W=67, A=24. Solenidium σ (104) medial and dorsal, φ (81) ventral. Solenidia ω1 and ω2 identical (30), blunt apex; ft´ anterior to ω1. Leg III (Fig. 32). Femora L=74, W=52; genua L=20, W=17; tibiae L=70, W=27; tarsi L=84, W=20. Solenidium σ (37) rigid, φ (81) located in a protuberance, little more than twice the size of σ. Leg IV (Fig. 33). Femora L=86, W=49; genua L=37, W=17; tibiae L=81, W=20; tarsi L=96, W=22. Solenidium φ (103) with a conspicuous thickening in the basal region (Fig. 39), insertion without cuticular fold.

Type material. Holotype (male) mounted on slide. 12/X/2012, Mexico, Veracruz, Estación de Biología Tropical , Los Tuxtlas, sample of soil and litter, L. Villagomez col. 18°35’02.04’’ N, 95°04’39.54’’ W. 242 m a.s.l. Five paratypes on slide with same data (1♀, 4♂). 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. UNAM.

Etymology. The specific name “ obsidiana ” refers to the color and brightness similar to volcanic obsidian stone.

Remarks. Pergalumna obsidiana sp. nov. has a strong resemblance to P. hypergranulosa sp. nov. by integumentary granulation, shape and position of porose areas and bothridial setae bs, however it may be easily differentiated by the shape and ornamentation of genital plates, interlamellar setae (in) inserted in L margin, presence of a rostral sclerotic extension, subcapitulum with anterior apex bilobed and more intense and shiny dark coloration. Furthermore, it differs from P. granulatus by barbulate bs in only one side and protuberances in genital plates, from P. elongatiporosa by the shape of A1, from P. paralongisetosa by having heavier granulation on the notogaster and from P. silvatica by four notogastric porose areas.

Figures

FIGURES 22 ‾ 25. Pergalumna obsidiana sp. nov. 22. Notogaster, dorsal view; 23. Ventral plate; 24. Lateral region, pteromorph and legs omitted; 25. Prodorsal setae. Scale bars 50 µm.

FIGURES 26 ‾ 30. Pergalumna obsidiana sp. nov. 26. Subcapitulum, ventral view; 27. Right pteromorph; 28. Left chelicera, antiaxial view; 29. Structure of cerotegument; 30. Left leg I of holotype, antiaxial view. Scale bars 20 µm.

FIGURES 31 ‾ 33. Pergalumna obsidiana sp. nov. 31. Left leg II of holotype, paraxial view; 32. Right leg III of holotype, antiaxial view; 33. Right leg IV of holotype, antiaxial view. Scale bars 20 µm.

FIGURES 34 ‾ 40. SEM images of Pergalumna obsidiana sp. nov. 34. Notogaster and prodorsum, dorsal view; 35. Ventral plate and subcapitulum, ventral view; 36. Rostrum, frontal view; 37. Prodorsum, lateral view; 38. Genital plates, showing ornamentation, triangular arrows indicate protuberances; 39. Left tibiae IV, showing detail of φ solenidium, arrows indicate thickening; 40. Cerotegumentary granulation, bothridial setae bs and interlamellar setae in.