Paracamisia osornensis, Olszanowski, Ziemowit & Norton, Roy A., 2002

Olszanowski, Ziemowit & Norton, Roy A., 2002, Paracamisia osornensis gen. n., sp. n. (Acari: Oribatida) from Valdivian forest soil in Chile, Zootaxa 25, pp. 1-15 : 3-14

Paracamisia osornensis sp. n.

Size, color

Adult body length: 830­850 Pm; maximum width: 435­455 Pm. Color: brown to dark brown. Amorphous cerotegument and debris moderately thick in humeral area and usually present as thin layer on subcapitulum, coxisterna and legs (especially basal segments); little or none on rest of notogaster, anogenital region or central region of prodorsum.

Prodorsum ( Figs. 1 , 3­7 , 14, 26­30)

Cuticle deeply and densely foveate, except immediately around bothridium and anterior to lamellar setae; foveae mostly 5­10 Pm across. Surface topography complex ( Figs. 1 , 28 ): with central raised region, delimited by strong, U­shaped contour between bothridia and lamellar setae; linear depression present in midline between bothridia; with paired swellings posterolateral to lamellar setae. Rostrum rounded, with small anterior convexity anteromedial to rostral setae ( Figs. 1 , 28 , 34 ). Rostral setae (ro) small, curved, delicately barbed, situated on inconspicuous tubercles ( Fig. 4 ). Lamellar setae (le) more than twice length of ro, relatively thick, curved, uniformly and distinctly barbed ( Fig. 5 ), set on very short apophyses. Interlamellar setae (in) delicately and sparsely ciliated, shorter and thinner than le ( Fig. 6 ). Sensilli (ss) relatively short; slightly broadened, flattened and barbed in distal third ( Figs. 7 , 14, 29). Bothridium with wall projecting from surface, posteriorly with weakly defined vertical ridges ( Fig. 29 ); internally with well developed, flattened, porose saccule. Exobothridial setae inserted on lateral wall of bothridium: ex1 minute, spiniform; ex2 represented only by alveolar vestiges (Fig. 14).

Notogaster ( Figs. 1­3 , 8­13 , 26, 27, 31 )

Notogaster ovoid in dorsal aspect, widest near middle. Strongly convex, smooth and shiny without longitudinal ridges or lateral folds and without suprapleural scissure separating dorsal and lateral parts of plate. Anteriorly with pair of shallow, oval concavities behind insertions of setae c2 and c3 and smaller, less conspicuous medial concavity between bases of setal pairs c1 and d1 ( Figs. 1 , 26, 28 ). Anterolaterally with groove running from near seta c2 obliquely toward venter ( Fig. 27 , arrow), spanned close to c2 by scale­like cuticular projections ( Fig. 31 ) that hide lyrifissure ia. Posteriorly with several poorly defined transverse folds ( Figs. 26, 27 , 33 ). With 15 pairs of notogastral setae plus vestiges of pair f2 located just anterior to bases of setae h1. Notogastral setae slightly curved, without apophysis or tubercle ( Figs. 8­13 ). Setae of various lengths but with two forms: setae of rows c, d, e, and f2 of moderate length, attenuate, with sparse delicate barbs or cilia ( Figs. 8­10 ); setae of rows p and h acuminate, more densely barbed and shorter, less than half length of e1 ( Figs. 11­13 ). Five pairs of lyrifissures (ia, im, ip, ih, ips) in positions normal for family. Opisthonotal gland large, with aperture (gla) aligned between setae f2 and h2.

FIGURES. 14­18. Paracamisia osornensis sp. n., paratype (except 15, from holotype): 14 ­ prodorsum, right bothridial region, lateral aspect; 15 ­ preanal plate, ventral aspect; 16 ­ subcapitulum, ventral aspect, palps omitted; 17 ­ right palp, antiaxial aspect; 18 ­ right chelicera, antiaxial aspect. Scale bars = 50 Pm.

Ventral region ( Figs. 2 , 15, 33­35)

Ventral cuticle without foveae. Coxisternal pairs delineated transversely and medially by well defined grooves; transverse grooves narrow, bordered by tubercles of various sizes; medial groove becomes broader posteriorly ( Figs. 2 , 35 ); dorsal cuticle of coxisternal extremities tuberculate ( Figs. 28, 30 ). Mentotectum of coxisterna I medially incised ( Figs. 34, 35 ). Coxisternal setation: 3­1­3­3; setae 1a ­c, 2a, 3a, 4b short, 3b, 3c, 4a, 4c distinctly longer, delicately ciliated. Genital plates subdivided by transverse band of hyaline, weakly sclerotized cuticle; setation variable, 17­21 relatively long, thin, attenuate setae aligned near medial margin of each plate. Aggenital and adanal plates fused, relatively broad and narrow, respectively, typical of family; two pairs of aggenital setae, similar to genital setae, on medial margin; three pairs of adanal setae short; lyrifissure iad distinct, anterior to and aligned with curved adanal row. Preanal plate distinct, triangular, porose (Fig. 15). Anal plates long, narrow, tapered anteriorly and posteriorly, bearing two pairs of short setae and lyrifissure ian. Ovipositor with 16 setae: three pairs of coronal (k) setae, two pairs on ventral lobe, and three setae on each lateral lobe; pairs \1 and W1 35 Pm long, thick, acuminate; other setae 10­12 Pm, spiniform; all but k setae eupathidial.

Gnathosoma (Figs. 16­18, 33)

Gnathosoma generally typical of family. Subcapitulum stenarthric; mental setae (h) and one pair of genal setae (a) thick, relatively long, second and third pairs of genal setae (m1 and m2) minute. Three pairs of adoral setae: or2 and or3 ciliated, normal in form, or3 (not illustrated) expanded, bifurcated distally, similar to that of Camisia (Grandjean 1957) . Palp setation (trochanter to tarsus) 0­1­0­3­7, plus baculiform, slightly curved, tarsal solenidion; tarsal seta sul eupathidial, but no canal discernable in other setae. Chelicera with Trägårdh’s organ well developed; setae ciliated, cha thicker than chb.

Legs ( Figs. 19­25 , 36, 37 )

Cuticle strongly foveate on much of each femur and on trochanters III, IV. Genua, tibiae, and distal parts of femora with shallow, irregular grooves. Tarsi monodactylous. Setation (legs I­IV, two of each leg studied): trochanters 1­1­5­1; femora 9­9­7­4; genua 5­5­5­ 5; tibiae 6­6­4­4; tarsi (famulus included, solenidia excluded) 28­26­24­23. Most setae of femora, genua and tibiae thick, acuminate or distally rounded, strongly barbed; some, particularly in dorsolateral positions (l) distally bifurcated ( Figs. 21 , 36 ). Proximodorsal setae of tarsus similar to those of more basal segments, but ventral setae mostly spiniform and distal setae mostly attenuate ( Fig. 19 ). Seta d of all genua and tibiae small, attenuate, inconspicuously barbed, and coupled to respective solenidion ( Fig. 36 ). Famulus (e, Figs. 19 , 37 ) simple, setiform. Only proral pair and subunguinal setae of tarsus I appear eupathidial. Solenidial formulae (legs I­IV): genua 1­1­1­1; tibiae 2­1­1­1; tarsi 3­2­0­0. Genual and tibial solenidia ceratiform, thinner than respective coupled setae d, but of similar length ( Fig. 36 ). Tibia I solenidion Q2 free standing, half the length of Q1, which is coupled to d. Tarsal solenidion Z1 ceratiform, slightly shorter than seta ft’; Z2 piliform, inserted between setae it’’ and p’’ and almost as long as former; Z3 short, ceratiform, inserted ventrad of famulus, which is similar in size and shape.

Material examined

The holotype female was collected 19­XII­1982 by A. Newton and M. Thayer from leaf litter in Valdivian rainforest, at approximately 430 m elevation, 4.1 km east of Anticura, in the Parque Nacionale Puyehue, Osorno Province, Chile (FMHD 82­711). Twelve paratypes have the same collecting data. Two other paratypes are also from the Parque Nacionale Puyehue, 425 m elevation, Aguas Calientes, collected 3­I­1985 by N. Platnick and O. Franke from Valdivian forest litter. The holotype and seven paratypes are deposited in The Field Museum (Chicago, Illinois); 1 paratype is in the Canadian National Collection (Ottawa, Canada), and the remaining paratypes are divided between the authors’ collections. All are preserved in ethanol, except for two dissected, slide mounted specimens retained by the authors.

Etymology

Named for the type locality, Osorno Province, Chile.

Remarks

1. Paracamisia osornensis has a notogaster unusual for a camisiid mite; it is convex, rather shiny, mostly free of debris, and lacks distinct ridges or other ornamentation. More surprising, it lacks a suprapleural scissure, unlike all other known family members. This scissure is a line of cuticular weakness that usually runs along a dorsolateral fold or carina, and separates a notaspis (dorsal plate) from paired pleuraspis (lateral plates). Even in Platynothrus capillatus , which has an unusual, evenly rounded notogaster, the scissure is evident in the anterior half of the sclerite.

2. All species of Camisiidae that have been studied appear to be asexual (Grandjean 1941, Norton & Palmer 1990, Palmer & Norton 1991a, b). The holotype and nine examined paratypes of P. osornensis are female (others were not cleared); although the sample size is small this species is probably also asexual (thelytokous).

3. The relationship between Paracamisia and other genera of Camisiidae is uncertain. In a preliminary study, we compared 19 characters among the five genera ( Table 1 ). If Nothridae and Nanhermanniidae are considered closest outgroups (see characters in Olszanowski 1996), Paracamisia has plesiomorphic, and therefore uninformative, states for nine of these characters (1, 3, 7­10, 12, 13, 19). Four other characters seem too variable within particular genera to be useful (2, 5, 6, 16, 17).

The remaining characters seem informative, but they are not all congruent. Two progressive synapomorphies (4, 14) support a clade containing of Heminothrus , Platynothrus and Paracamisia . The porose bothridial saccule of Platynothrus seems to be a respiratory structure (Alberti et al. 1997) and that of Heminothrus and Paracamisia are similar, at least based on their cuticular structure. The slight porose outpocketing in the Neonothrus bothridium may be a precursor to this saccule; if true, it would support Neonothrus as the sister group of this clade. The transverse genital desclerotization exhibited in the three former genera is an apomorphy not otherwise found in Desmonomata, but similar states are found in Mixonomata (Perlohmanniidae) and basal Brachypylina ( Liodidae ). One regressive synapomorphy (11) supports a clade containing Platynothrus and Paracamisia . The loss of seta d from the palp genu is rare among Desmonomata (see Travé 1992), known elsewhere only in some Nanhermanniidae ( Nanhermannia spp.), where it was probably lost independently. However, the absence of femoral seta inf is an incongruent loss, being shared with Camisia .

From this simple analysis, no clear autapomorphy can yet be ascribed to Platynothrus , so it could be argued that Paracamisia is simply a highly derived member of that genus deserving at most only subgeneric status. We reject this because Platynothrus has yet to be well characterized (many non­holarctic species are poorly known) and also because of the uncertainty posed by character 15. Neonothrus, Heminothrus and Platynothrus have a submarginal carina that demarcates the medial band where genital setae insert; Paracamisia lacks this progressive synapomorphy.

Figures

FIGURE. 3. Paracamisia osornensis sp. n., paratype, lateral aspect. Scale bar = 100 Pm.

FIGURES. 4 ­ 13. Paracamisia osornensis sp. n., holotype (except 12, from paratype) dorsal aspects: 4 ­ seta ro; 5 ­ seta le; 6 ­ seta in; 7 ­ sensillus; 8 ­ seta c 3; 9 ­ seta d 1; 10 ­ seta d 2 and opisthonotal gland opening; 11 ­ seta h 1 and vestigial alveolus of seta f 1; 12 ­ seta h 1 (variation); 13 ­ seta p 1. Scale bar = 50 Pm.

FIGURE 19. Paracamisia osornensis sp. n., paratype, distal part of right tarsus I, antiaxial aspect. Scale bar = 50 Pm.

FIGURES. 20 ­ 22. Paracamisia osornensis sp. n., paratype, antiaxial aspect: 20 ­ right leg I; 21 ­ seta l of genu I; 22 ­ right leg II. Scale bars = 100 Pm.

FIGURES. 23 ­ 25. Paracamisia osornensis sp. n., paratype, antiaxial aspect: 23 ­ right leg III; 24 ­ right leg IV, 25 ­ deformed leg IV. Scale bar = 100 Pm.

FIGURES 1 ­ 2. Paracamisia osornensis sp. n., holotype female; 1, dorsal aspect, legs and most of gnathosoma omitted; 2, ventral aspect, legs omitted. Scale bar = 100 Pm.

FIGURES 26 ­ 31. Paracamisia osornensis sp. n., scanning electron micrographs: 26 ­ dorsal aspect, 27 ­ right lateral aspect (using Robinson back­scatter detector; arrow indicates location of Fig. 31), 28 ­ anterior aspect of prodorsum and surrounding structures (bo, bothridium; le, lamellar seta; in, interlamellar seta), 29 ­ bothridium and sensillus right lateral aspect, 30 ­ anterior region, right lateral aspect, 31 ­ notogastral seta c 3, with lateral groove and spanning scale­like cuticular projections. Specimens cleaned of cerotegument and debris. Scale bars = 100 m (26, 27), 50 m (28, 30), 20 m (32), 10 m (29, 31).

FIGURES 32 ­ 37. Paracamisia osornensis sp. n., scanning electron micrographs: 32 ­ posterior half, ventral aspect (using Robinson back­scatter detector), 33 ­ subcapitulum and surrounding structures, ventral aspect (arrow on incision of mental tectum), 34 ­ right coxisternal region, ventral aspect, anterior to lower right (I, II, III ­ coxisterna), 35 ­ legs I and II, right lateral aspect, 36 ­ upper part of right genu I, lateral aspect, showing coupled seta d and solenidion n, plus distally bifurcated seta l ʹ, 37 ­ upper proximal region of right tarsus I, lateral aspect, showing tarsal cluster of seta ft ʹ, solenidion, and famulus (e). Specimens cleaned of cerotegument and debris. Scale 1 bars = 50 m (32, 35), 20 m (33, 34), 5 m (36, 37).

Tables

TABLE 1. Comparison of adult character states shared between Paracamisia and at least one other genus of Camisiidae (Characters of previously described genera mostly from Olszanowski 1996).

Character	Camisia	Neonothrus	Heminothrus s.s.	Platynothrus	Paracamisia
1. Prodorsal cuticle	not or weakly foveate	strongly foveate	strongly foveate	strongly foveate	strongly foveate
2. Shape of sensillus	short, clavate	setiform	setiform or slightly broadened distally	setiform or slightly broadened distally	broadened distally
3. Exobothridial setae ex 1	alveolar vestige	present	present	present	present
4. Bothridial saccule	absent	absent1	present	present	present
5. Notogaster dorsum	flattened	flattened	flattened	flattened or (rarely) convex 2	convex
6. Longitudinal carinae on notogaster	present or absent	present	present or absent	present or absent	absent
7. Notogastral seta f 1	vestigial or formed	vestigial	vestigial	vestigial3	vestigial
8. Posterior notogastral setae inserted on apophyses	yes	no	yes	no	no
9. Caudal region arranged into complex folds	yes	no	yes/no	no	no
10. Posterior margin of notogaster (ventral aspect)	perpendicular to anal plates	parallel to anal plates	parallel to anal plates	parallel to anal plates	parallel to anal plates
11. Palp setation (tro­ chanter to tarsus)	0­1­1­2­7 or 0­1­1­1­7	0­2­1­3­7	0­2­1­3­7	0­1­0­3­7	0­1­0­3­7
12. Genal setae (m)	absent	2 pairs	2 pairs	1or 2 pairs	2 pairs
13. Coxisternal setation	3­1­3­3 or 3­1­2­3	3­1­3­3	3­1­3­3	3­1­3­3	3­1­3­3
14. Genital plate sclerotization	continuous	continuous	transverse desclero­ tized band	transverse descle­ rotized band	transverse descle­ rotized band
15. Genital plate with submarginal carina	no	yes	yes	yes	no
16. No. of genital setae per plate	9­20	12­13	9­23	13­25	17­21
17. Pairs of anal setae	3	2	2	2	2
18. No. of tarsal claws	3 or 1	1	1	1	1
19. Solenidial formulae (I to IV): genua tibiae tarsi	1­1­1­0 1­1­1­1 1­1­0­0	1­1­1­1 2­1­1­1 3­2­0­0	1­1­1­1 2­1­1­1 3­2­0­0	1­1­1­1 2­1­1­1 3­2­0­0	1­1­1­1 2­1­1­1 3­2­0­0

1 The internal bothridial wall of Neonothrus humicolus has a very slight porose outpocketing, discernable only in certain orientations.

2 The notogaster of Platynothrus capillatus is strongly convex. 3 Platynothrus capillatus may form seta f or not.

1