Penthalodes hawaiiensis Jesionowska, 2010, n. sp.
Creators: name: Jesionowska, Katarzyna
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Prostigmata
Penthalodidae
Penthalodes
Penthalodes hawaiiensis

description: Penthalodes hawaiiensis n. sp.
Synonym: P. ovalis Strandtmann & Goff, 1978, Pacific Insects 19, 3–4, 121–143.
Locus typicus: Hawaii, vicinity of Volcano-Hilo road, samples from grass, lichen, treefern forest, cane fields
Diagnosis. Epirostrum trilobed; middle part of epirostrum large, triangular; lateral lobes weakly developed with slightly pointed, resembling triangles. Dorsal idiosomal setae, except setae ro and bo, loosely feathered. Rhagidial organ I with two recumbent baculiform solenidia, in tandem, in confluent depressions and one tiny spatulate solenidion in separate pit inserted laterally antiaxially in relation to rhagidial organ I. Famulus absent. Rhagidial organ II with three recumbent baculiform solenidia, staggered, in confluent depressions. Solenidia of rhagidial organ II of unequal size, not overlapping each other.
For the original description and deposition of type specimens see Strandtmann and Goff (1978).
Penthalodes polonicus n. sp. (Figs 1–7)
Diagnosis. Epirostrum trilobed, lateral lobes broadly rounded; in lateral view, base of epirostrum sloping; without reticulation. Dorsal idiosomal setae, except setae ro and bo, tridactylate, with short stem. Rhagidial organ of tarsus I with two banana-shaped solenidia in tandem in a confluent depressions and one T-shaped solenidion in a separate pit inserted laterally to proximal solenidion. Small stellate famulus inserted laterally on mid-region of tarsus I, well separated from rhagidial organ. Rhagidial organ of tarsus II with three thin baculiform solenidia, in tandem, in a common depression with the distal part of each solenidion overlapping the preceding one. One, small spine-like solenidion (possibly a famulus) inserted in pit laterally to rhagidial organ II, at the level of proximal solenidion.
Description. Body with well developed ornamentation, moderately sclerotized. Idiosoma angular (Fig. 3) with ornamental costulae forming pentagons (i.e. reticulate pattern). Dorsum with two “V”-shaped furrows. Idiosomal length (excluding epirostrum) about 400 µm, width (at the level of setae c 2) about 250 µm. Legs shorter than idiosoma. Ratio of idiosomal length to leg I length: 1:15.
Aspidosoma. (Figs 1, 2, 3C, D) Prodorsum forms a steep anterior wall of idiosoma. Ornamentation consists of large tear-shaped costulae (i.e. point-shaped with tiny spine) and minute costulae discernible as dots. Large costulae form pentagons, while minute costulae form parallel lines on the surface of each pentagon. Naso small, smooth, and spherical, with one hemisphere hidden in a cavity. Epirostrum trilobed with lateral lobes broadly rounded, distinctly shorter than medial lobe (Figs 3 CD). Four pairs of prodorsal setae: ro, bo, le, xa (about 6, 56, 37 and 25 long, respectively). Setae ro tiny, nude, inserted on frontal surface of naso, adjacent in a common depression (possibly a result of slide-mounting). Setae bo filiform, inserted on prodorsum in deep bothridia dorsally; setae le and xa situated frontally. Setae le and xa tridactylate with short basal branches. V-shaped furrows start lateral to setae bo. Transverse furrow separating prodorsum from opisthosoma absent.
FIGURE 1. Penthalodes polonicus n. sp. Female. (A) Dorsum; prodorsal setae: ro, le, bo, xa; opisthosomal setae: c 1, c 2, d, e, f, h, ps, ad. Lyrifissures: ia, im, ip, ih. (B) Venter; coxal regions: cx 1–4; trochanter: tr 1–4; aggenital setae: ag 1–8; anal setae: an.
Gnathosoma (Figs 3 AB, 4). Subcapitulum (Fig. 4 AB) about 110 long, conical, with well developed ornamentation comprising spine- to point-shaped costulae on smooth integument. Lateral lips (LL) connected by a smooth membrane dorsally for approximately two thirds their total length. Ventrally, the free parts of lateral lips bear one pair of setae n, inserted slightly distal to labial apex; and one pair of setae m laterobasally. Setae n and m plumose with long outgrowths. On ventral side, lateral lips fused to hypostome (H), delimited by sclerites sc. Top of hypostome forms small labium (LI). Hypostome divided by inner sclerite into a basal rectangular and distal triangular part. Paraxial surfaces of free part of lateral lips, as well as the ventral part of labrum (LB), strongly sclerotized. Distal antiaxial parts of lateral lips smooth and plicate. Adoral setae difficult to discern. Free part of labrum not longer than those of lateral lips. Chelicera (Fig. 3 AB) about 115 long, elongated, ornamented with tiny spines. Cheliceral seta absent. Fixed digit hood-shaped, distally bifurcate covering most of movable digit. Movable digit strongly sclerotized, narrows distally into hooked claw. Pedipalps (Fig. 4 CD) four-segmented, Tr-FG-Tb-Ts; coxal regions well formed and fused partially with dorso-basal subcapitulum (Fig. 4 B). Pedipalp about 166 long, Tr to Ts: 25-55-57-29. Number of setae and solenidia: 0-2-3-9(1). Setae on femorogenu (d 1-15, d 2-21 long) and tibia (d 1-18, lt -11, d 2-13 long) plumose. Seta d 2 on FG with a very long terminal spine. Pedipalpal tarsus elongated, sharply tipped, linear in profile with nine setae and one recumbent solenidion in depression dorsally; seta acmg (= d; 10 long) thick, pilose, angled basally, the largest; seta cm ' (11 long) positioned paraxially, almost smooth, spiralled; seta ul '' slightly thickened, shortly pilose; setae ul ', u '' and u ' (5 long each) cylindrical, hollow, each terminating in strong sclerotized solid (black) carina; seta a (7 long), thickened, with distal spine; setae s plumose, la '' pilose, very short (3 and 4 long, respectively). Ventro-distal part of tibia terminating in distinct spine-like process.
Opisthosoma (Figs 1, 2; Table 1). Opisthosoma with characteristic “V”-shaped furrows, lacking any transverse furrows (as “das” or disjugal furrow). Ornamentation same as prodorsum, i.e. tear-shaped costulae forming pentagons, each covered by minute point-shaped costulae forming parallel lines (Fig. 1). Ornamentation on opisthosoma venter more delicate, with costulae being visibly smaller than dorsal costulae.
Opisthosoma composed of nine fused segments: C, D, E, F, H, PS, AD, AN, PE. Segment C with two pairs of setae c 1 and c 2; c 2 inserted slightly distad of c 1, almost at the level of setae bo. Segments D to AN with one pair of setae each, i.e., d, e, f, h, ps, ad and an, respectively. Segments H to PE form the posterior wall of the opisthosoma which is steep, beginning at about the level of setae h (Fig. 2). Distances between insertions of setae ps-ad, ad-an are almost equal and rows of these setae arranged one under another; setae ad well distant of anal cleft, hence the anal cleft is accompanied by only one pair of setae, an. Setal pair f aligned with lyrifissures ip. Setae h are inserted laterally and well posterior to setae f and lyrifissures ip. V-furrows end about at the level of setae f. Distances between insertions of opisthosomal setae distinctly longer than length of setae. Opisthosomal setae c to ad tridactylate with short stem, and prominent medial “dactyl”. With four pairs of lyrifissures (ia, im, ip, ih?), slit-like with strong sclerotized margins. Anal cleft very short, positioned terminally. Anal valves well developed, inserted on a small protuberance of segment PE. Setae an plumose, close to anterior margin of PE, similar to genital setae.
Genital region (Figs 1B, 5; Table 2). Costulae forming pentagons and irregular lines or points, distinctly smaller and not as homogenous as those on dorsum. Reticulation distinct in pregenital area, but punctate in lateral aggenital region. Genital valves strongly sclerotized, well separated from aggenital region, differently ornamented with irregular tiny spines. Between coxal regions IV and genital valves (pregenital area) eight aggenital setae form two alignments, the first with six and the second with two setae; another four pairs of aggenital setae are arranged lateral to the genital valves (i.e. total aggenital setae = 16). Nine pairs of plumose genital setae, inserted close to inner margin of genital valves except for the laterally situated fifth pair. Seven pairs of plumose eugenital setae, most probably eupathidial in form, inserted on well sclerotized protuberances. Two pairs of genital papillae.
Podosoma (Figs 1B, 2, 6, 7). Coxal regions well developed, strongly sclerotized and ornamented; dorsolateral surface rugose, especially on coxal regions I and II. Ornament on podosoma delicately punctate; between coxal regions IV with delicate pentagons. Contiguous coxal regions I and II clearly separated from contiguous coxal regions III and IV; coxal formula: 2-1-2-1. Sternal region well developed, much more delicately ornamented than coxal regions; sternal formula: 2-0-2-2. Sternal and coxal setae plumose.
Legs (Figs 6, 7). Legs shorter than idiosoma, leg I 348 long, Tr-Ts 30-110-50-58-100 long, leg II 265 (30- 75-40-50-70 long), leg III 275 (30-85-40-50-70 long), leg IV 325 (30-100-50-65-80 long). Chaetotaxy and solenidiotaxy (in parentheses) for legs I to IV: Tr 1-1-1-1, F 9-7-5-7, G 5(1+f)-5(1+f)-5(1)-4(1), Tb 6(2)-6(2)- 6(1)-6(1), Ts 23(2+1+f)-16(3+1)-15-15. Solenidia inserted dorsally, smooth, without striae. Rhagidial organ I with two banana-shaped solenidia (10 long each) in tandem in confluent depressions (Figs 6 A, 7A). Distal depression below proximal depression, shorter than solenidion. Laterally, at level of proximal solenidion, one T-shaped solenidion (6 long) inserted in pit which is considerably larger than solenidion. Small stellate famulus positioned more proximally, completely distant from rhagidial organ I. Rhagidial organ II with three thin, baculiform solenidia (11, 10 and 9 long, respectively), in tandem in common depression; proximal FIGURE 5. Penthalodes polonicus n. sp. Genital region. Genital valve with nine genital setae, g 1- g 9; seven pairs of eugenital setae, eug 1- eug 7; two pairs of genital papillae, pap1-2.
solenidion the thickest; solenidia adjacent and overlapping one another because distal part of depression is positioned below proximal part (like cascade) (Figs 6 B, 7B). Spine-like tiny solenidion (or famulus; 2 long) in small pit lateral to proximal solenidion. Tibia I with two dorsodistal solenidia, proximal solenidion (6 long) erect and baculiform, distal solenidion (8 long) banana-shaped, recumbent in depression; distal solenidion thickest; distance between solenidia 9. Tibia II with two dorsodistal solenidia; proximal solenidion (5 long), rod-like, distal solenidion (10 long) thick, banana-shaped, in depression; distance between solenidia 6. Tibia III and IV each with one erect, baculiform dorsoproximal solenidion (6 and 7 long, respectively). Genua I–IV each distally with large (especially large on G I, II and IV) banana-shaped solenidion (13, 13, 9 and 13 long, respectively); genu I and II each with tiny spiniform famulus (4 and 3 long, respectively; in own pore) located near distal margin of article; famulus on genu I with one lateral spine (bifurcate). Three pairs of setae expanded distally near apotele I-IV each. All leg setae shorter than leg article, plumose with long distal outgrowths (spicule), especially long on femur II setae. Ventral tarsal setae angled basally, i.e. foot-shaped. Leg integument strongly sclerotized with ornamentation composed of tiny spines and minute tubercles. Apotele I–IV each with ambulacrum composed of two claws and pad-like, setuled empodium. Ambulacrum of leg IV the largest.
Material examined. Female holotype (KJJ724-1), Zakopane. Tatrzański Park Narodowy (The Tatra Mountains National Park). Dolina Chochołowska (Chochołowska Valley). Stone under the peaks of "Olejarnia" in Niżna Brama Chochołowska; mosses, grass and soil. 20.09.1979. Leg. J. Rafalski. Three females, same data as holotype. Further material examined: two females (one paratype KJJ797-2), Zakopane. The Tatra Mountains National Park. "Wąwóz Kraków" (Krakow Ravine); mosses, grass, soil and detritus from stone cracks and cavities (limestone). 10.10.1983. Leg. Z. Olszanowski.
The material is deposited in the author's collection. In future, specimens will be transferred to the Acarological Collection of the Faculty of Biology, Adam Mickiewicz University, Poznań.
Etymology. The species name refers to the Polish part of the Tatra Mountains.
Differential diagnosis. This new species, although also European, differs from P. ovalis sensu Kaluz in the following combination of characteristics: (1) setae ro adjacent, i.e., inserted close to each other; (2) dorsal idiosomal setae tridactylate (except setae ro and bo); (3) epirostrum with weakly developed semi-round lateral lobes; (4) epirostral ornamentation composed of irregular tubercles, not pentagons or reticular pattern; (5) solenidia in rhagidial organ I banana-shaped, in tandem in confluent depressions; not lanceolate; (6) all solenidia in the rhagidial organ II in tandem, slightly overlapping each other, thin and baculiform, none lanceolate; (7) lateral solenidion on tarsus I T-shaped, not spiniform; (8) pedipalpal tarsus elongated, linear in profile; (9) stellate famulus on tarsus I well removed from rhagidial organ I; (10) number of aggenital setae 16, not 23; in pregenital region, eight setae in two alignments (six and two, respectively), not 13 (five and eight, respectively); (11) seven pairs of eugenital setae.
In P. ovalis sensu Kaluz (2000), the solenidia on tarsi I and II are arranged in a specific way. Rhagidial organ I has two lanceolate solenidia arranged linearly in separate depressions, with a third spiniform solenidion placed laterally in a pit. Rhagidial organ II has a lanceolate proximal solenidion placed separately from two parallel distal solenidia in a common depression.
Species Aggenital setae in pregenital Rest of Total sum of Genital setae
region aggenital setae aggenital setae
first second
alignment alignment
P. o v a l i s sensu Kaluz 2000 (Fig.2) 5 8 10 23 9+9 Morphological survey of hitherto described representatives of the Penthalodes. Eight species of Penthalodes are now identifiable. Four species, P. alaskaensis sp. n., P. boneti, P. oregonensis and P. t u r n e r i, are known from North and Central America (Baker 1946; Strandmann 1971), two species, P. ovalis and P. polonicus sp. n. are from Europe (Kaluz 2000; present paper), P. c a r i n a t u s is from Japan (Shiba 1978), and P. hawaiiensis sp. n. is from Hawaii (Strandmann & Goff 1978).
The descriptions by Baker (1946), Strandmann (1971) and Strandmann & Goff (1978) are all lacking detail to some degree, but allow their recognition as distinct species. Baker’s (1946) description details the shape of epirostrum, an important feature for separating these species. Nevertheless, drawings of rhagidial organ I and II and detail of other leg solenidia are lacking. Some data, now considered important in descriptions, are also missing from Strandmann (1971) and Strandmann & Goff (1978).
Shiba's (1978) description of P. carinatus is also brief, but is supported by drawings where, among others, the shape and the arrangement of solenidia on the tarsi and tibiae of legs I and II, as well as the shape of the epirostrum, distinguish this species from all others. However, Shiba (1978) thought the main character distinguishing it from similar species (P. ovalis and P. boneti) was the presence of eight pairs of genital setae. The redescription of P. ovalis by Kaluz (2000) presents good drawings for his putative P. ovalis specimens collected in Slovakia and Turkey.
Thor and Willmann (1941) promoted the use of the name P. ovalis, and the genus Penthalodes, by presenting a list of diagnostic characters for the genus: (1) epirostrum present; (2) reticulate ornament of the body composed of tetragons, pentagons or hexagons; (3) furrows in the form of the letter V on dorsum; (4) no epivertex (i.e. naso); instead of it, an eye-like organ with a pair of rudimentary hairs; (5) legs shorter than the body; and (6) setae of the body very small, plumose or branched. Due to Thor and Wilmann’s (1941) work, most ecological works and check-lists use the name P. ovalis when they probably mean Penthalodes sp., because many do not make proper reference to the species-level characteristics.
The following morphological review allows for a new understanding of the characteristic features of adults of the genus Penthalodes, comparisons to other representatives of the Eupodoidea, and the new diagnoses and species already presented in this work.
Idiosoma. The idiosoma has characteristic shape; angular in profile, while being slightly narrowed posteriorly in dorsal view. Its anterior and posterior part is steep (Fig. 2). When viewed in lactic acid, it can be flattened laterally. Other authors describe it as plump, ovoid or almost globose. On the dorsum, there are characteristic furrows arranged like the letter “V” or “ Y ”, depending on slide preparation.
Epirostrum. This structure resembles a small roof over the gnathosoma. The epirostrum is positioned well below the naso and is either trilobed or monolobed (Table 3). The central lobe is always obviously the largest. The epirostrum of Penthalodes sp. presented by Baker (1987) is most similar to P. t u r n e r i. Ornamentation on the epirostrum is usually reticulate in the basal part, and linear or punctate in the apical part, but does vary in some species. The profile of the epirostrum can differ, e.g. the dorsal line can be sloping from the base, as in P. polonicus, or can initially form a small platform (like in other representatives of the genus collected in Poland, Fig. 3 E). The epirostrum does not occur in the larva and tritonymph (Jesionowska 1996; Strandtmann 1971).
carinatus 1 Triangular; edges slightly plicate Wholly reticulate
turneri 1 Triangular with rounded apex Basally reticulate, apically
striate
boneti 1 Rectangular or trapezoidal transformed medially into ligulate Basally reticulate, apically
process, cusps slightly pointed striate
oregonensis 1 Large, undivided, lobed, with broadly rounded apical part Basally punctuate, distally
with tiny hairs Naso. The naso of Penthalodes is unique. It is spherical, smooth and completely disconnected from the epirostrum below. Only the anterior hemisphere of the naso is visible in dorsal view, while the other hemisphere is hidden in a cavity of the prodorsum wall. Strandtmann and Goff (1978) observed that the naso is submerged in the anterior part of idiosoma. A detailed description of the appearance of the naso is presented by Haupt and Coineau (2002), and its scanning electron micrograph is given by Baker (1990). The naso bears a pair of minute, nude, unbranched setae ro. Thor and Willmann (1941) considered the naso absent, but instead a an eye-like structure (organ) with a pair of rudimentary setae.
Idiosomal setae, except setae of the genital region and podosoma (Table 1). The number and the arrangement of idiosomal setae are characteristic for Penthalodes. They lack setae d 1 and e.l. (Strandtmann 1971), which are usually found in other Eupodoidea, making just 13 pairs of idiosomal setae, of which four pairs fall on the prodorsum and nine pairs on the opisthosoma. Because the idiosoma is angular (geometric solid body), some setae are located on the steep walls of its anterior and posterior parts (Fig. 2). Therefore, it is difficult to be confident about setal names of the dorsum and the venter because they can optically change their location after flattening of the idiosoma. For example, setae c 2 may be placed slightly anterior to c 1, giving the illusion that they are prodorsal setae.
Strandtmann (1971) and Baker (1987) considered Penthalodes with four pairs of prodorsal and nine pairs of opisthosomal setae, contrary to Kaluz (2000) who proposed an unusual arrangement of five pairs of prodorsal and eight pairs of opisthosomal setae. The prodorsal setae are thought to be iv, ev 1, ev 2, T and sc. The extra prodorsal setae are obtained by considering the opisthosomal setae c 2 as the scapular setae sc. Five pairs of prodorsal setae are atypical for Eupodoidea, which have just four pairs of fundamental prodorsal setae. Baker (1987) distinguishes nine pairs of opisthosomal setae with total lack of setae h, whereas Kaluz presents only one pair of these setae (instead of two pairs like in other Eupodoidea). They both recognize two pairs of setae f, i.e. f 1 and f 2, and setae ps, –according to Kaluz- two pairs of setae ps, and -according to Baker- three pairs of these setae.
Here, I follow Strandmann (1971) by considering Penthalodes to have four prodorsal, and nine opisthosomal pairs of setae. In my opinion there are two pairs of setae c, c 1 and c 2, and only one pair of setae on segment from D to AN each, particularly only one pair of setae f and h (differently than Baker and Kaluz). Three pairs of setae ps (ps 1, ps 2, ps 3 according to Baker), I recognize as ps, ad, and an, respectively (Table 1). With only one pair of setae accompanying the anal cleft (an), not three or two.
Setae c 1 and d are positioned between furrows “V” and lyrifissures ia externally. Setal pair e lies laterally in relation to the furrows. Setae f are aligned with lyrifissures ip, and are lateral in relation to the “V” furrows. Setae h form a separate row posterior to setae f and situated more laterally than the other setae because the opisthosoma changes into steep wall at this position. One pair each of setae ps, ad and an lie at this posterior wall of the opisthosoma one under another. Only setae an are placed in close vicinity to the anal cleft (see also in larva, Jesionowska 1996). This idiosomal chaetotaxy is also characteristic of Protopenthalodes and Hawaiieupodes (Jesionowska 1989, 2008).
On the scanning electron micrograph published by Baker (Fig.19d in 1990), the arrangement of setae on the posterior part of idiosoma is visible, illustrating three pairs of setae, ps 1, ps 2 and ps 3. Setae ps 1 are more removed from each other than setae ps 2, while setae ps 2 are more removed than setae ps 3. This arrangement is usually different in other Eupodoidea. Moreover, distances between rows of these setae are considerable and seem to be equal, although setae ps 1 are located at a slightly larger distance from setae ps 2 compared with the distance between setae ps 2 and ps 3. It is clearly visible that three pairs of setae are placed one under another because the opisthosoma forms a steep wall in this place. The very short anal cleft has anal valves and is located on a semispherical protuberance (also visible on the photo in Baker 1990). Earlier, Thor and Willmann (1941) observed that the anal opening is located terminally and on a protuberance. This suggests the existence of a tiny peranal segment, PE. Proximally, just in front of it, there is a pair of setae ps 3 according to Baker, but in my opinion it is a pair of setae an. When assuming that segments form rings (which is showed by location of setae ps, ad and an), it is difficult to imagine one large segment PS with three pairs of setae one under another with a simultaneous lack of segment H and setae h. The location of setae ps 1, ps 2 and ps 3, i.e. ps, ad and an respectively, shows in this case that most probably there are three separate segments, namely PS, AD and AN, each with one pair of setae, while the terminally located anus lies on the last segment, i.e. on PE (Table 1; Fig. 2).
The structure of idiosomal setae can differ, with prodorsal setae (except setae ro and bo) being usually much larger than opisthosomal setae (especially well visible on Fig. 1 in Kaluz 2000). Thor and Willmann (1941) observed that setae in P. o v a l i s are very small, plumose or branched. Setae in specimens described by Kaluz (2000) are branched with few outgrowths. Baker (1946), when comparing P. boneti with P. ovatus Koch (i.e. P. o v a l i s), found that the form of setae of the dorsum differs. In P. boneti, branches are short, while in P. ovatus they are less numerous and can be as long as the main stem. This feature approximates P. ovatus to the newly described species, i.e. P. polonicus, where setae are tridactyl, although prodorsal setae xa and le also have short outgrowths at the base of the stem. On the other hand, in P. t u r n e r i Baker (1946) distinguishes setae on the dorsum as “semi-plumose”, with three to five lateral branches, while the anterior setae are “six-rayed”. This resembles the shape of setae on the dorsum of P. ovalis described by Kaluz (2000). In Penthalodes sp. presented by Baker (1987), the setae are short and not loosely feathered, with a long apical spine, while in P. ovalis they are "densely spinose terminating in long filament" (Baker 1990). In P. oregonensis and P. carinatus, the setae are pilose rather than weakly plumose. In P. alaskaensis, they are plumose, while those in P. hawaiiensis are loosely plumose, with a longer apical outgrowth and sometimes also with some slightly longer lateral outgrowth. Usually, the podosomal setae and those of the genital region and a pair of setae an differ from other idiosomal setae, being plumose-pilose, which is particularly well shown in P. p o l o n i c u s and P. o v a l i s sensu Kaluz.
Lyrifissures. In all species of Penthalodes, lyrifissures are distinct and always present as four pairs (ia, im, ip, ih?). Lyrifissures ia, im and ip are lateral to furrows V, with ia situated slightly posterior to setae c 1, im slightly anterior to setae e, and ip at the same level as setae f. The last pair, ih, is positioned on the ventral side of opisthosoma anterior to setae an. The lyrifissures are slit-shaped with heavily sclerotized margins and arranged transversally.
Genital region (Table 2). The number of setae of the genital region in Penthalodes is variable. However, the arrangement of aggenital setae on the region between the coxal regions IV and the anterior margin of the genital valves (i.e. the pregenital region) is characteristic for Penthalodes, being composed of two alignments. The other setae are arranged in a line around the genital valves. The number of setae in each alignment varies. For example, in P. ovalis sensu Kaluz (Fig. 2 in 2000), the two alignments of aggenital setae in the pregenital region comprises five setae in the outer row, and eight setae in the inner row; the remaining five pairs of setae are arranged around the genital valves (23 setae in total). In P. polonicus, six setae form the outer row and two setae form the inner row; the remaining number of setae is four pairs (16 in total; Fig. 1B). Other examples are presented in table 2. For P. ovalis specimens presented by Baker (1987), as well as specimens of P. hawaiiensis and P. oregonensis, there is no information on the aggenital region. The number of aggenital setae in Penthalodes representatives ranges from 12 to 23 setae and may fluctuate, in particular in the pregenital region.
The genital setae are inserted on strongly sclerotized genital valves, arranged linearly, close to the inner margin, usually with one pair situated more laterally. The number of genital setae varies from 6 to 10 pairs between species (Table 2). In P. o v a l i s sensu Baker (1990) the number of genital setae can be inferred from drawing only.
The number of eugenital setae has earlier been mentioned only by Strandtmann (1978) and Kaluz (2000) as six pairs in P. ovalis sensu Kaluz, contrary to P. hawaiiensis and P. p o l o n i c u s, where there are seven pairs of setae.
Ornamentation of the idiosoma. The integument of Penthalodes species is moderately sclerotized with characteristic reticulate ornamentation formed by tiny, tubercular costulae creating pentagons and hexagons. The ornamentation is best discerned dorsally where costulae are large and distinct. On the other hand, the pattern is much more delicate, smaller on lateral and ventral parts, and can even disappear in the sternal region where it may be delicately punctate (particularly in the location of sejugal furrow). Around the genital valves, i.e. in the aggenital region, the delicate reticulate pattern sometimes disappears and tiny costulae form an irregular punctation, as in P. polonicus, whereas in other representatives, e.g. in P. alaskaensis, the reticulate ornamentation can be preserved. The coxal regions are strongly sclerotized, with a punctate or reticulate pattern, or a combination of punctate and reticulate ornamentation. In P. polonicus, there are sigillae visible between the coxal regions II and III, indicating the region of the sejugal furrow.
The lateral margins of the pentagons are formed by tubercular costulae which can be tear-shaped (more or less elongated), like in P. polonicus (Fig. 1), or have a broad basis terminating in a hook-like process, like in some P. ovalis (Baker 1990), or resemble a pyramid (Kaluz 2000). The surface area of the pentagons can be covered by tiny costulae in the form of dots forming parallel lines, like in P. p o l o n i c u s and P. ovalis sensu Baker (1990), or can be visibly lined with single tiny costulae, like in P. c a r i n a t u s, or smooth, like in P. ovalis sensu Kaluz. Penthalodes hawaiiensis has an ornamentation composed mainly of hexagons, with single spines arranged rather irregularly within their areas. In some representatives of Penthalodes there are sometimes single, additional, large tubercular costulae on the pentagon surface. This may occur in all species.
In P. ovalis sensu Kaluz, the polygonal reticulate ornament occurs on the whole surface of the idiosoma, except the sternal region, and in some specimens, this polygonal pattern on the dorsum can be disturbed. In P. boneti the pattern is similar: a reticulate pattern between the coxal regions, except the sternal region where it becomes tuberculate (punctate). According to Baker (1946), it is similar to the ornamentation of P. ovatus (i.e. P. ovalis). In P. carinatus, the reticulate pattern of the whole idiosoma is composed of pentagons and hexagons. In P. t u r n e r i and P. oregonensis, it is composed of hexagons on the whole idiosoma (Baker 1946). In P. a l a s k a e n s i s, the reticulate pattern occurs on the whole idiosoma but clear, regular pentagons and hexagons are most distinct on the dorsum and the ornament on the sternal region is reticulato-punctate (Strandtmann 1971). It is similar in P. polonicus.
ovalis sensu 2+1 lanceolate sharply tipped; third small rod- in line in separate depressions; third laterally Kaluz (2000) like
Penthalodes Solenidia of rhagidial organ II hawaiiensis 3+1(f?) baculiform, unequal size: proximal longest and thickest; staggered in confluent depressions distal smallest and thinnest; fourth tiny spine-like
posteriorly
polonicus 3+1(f?) thin baculiform, almost equal, proximal thickest; fourth in tandem in common depression, tiny spine-like laterally overlapping one another
turneri 3 rod-like in line
Rhagidial organs, solenidia and leg setae (Tables 4, 5). The rhagidial organ on tarsus I consists of two dorsal solenidia and a small lateral solenidion. The rhagidial organ on tarsus II consists of three dorsal solenidia and a small, rod-like solenidion (or famulus?) lying laterally in a separate pit. Species differences result from solenidia shape, the manner of their arrangement as well as whether they lie in common or separate depressions. It seems that in species of Penthalodes there are no famuli typical of other Eupodoidea. Most probably they are replaced by a tiny solenidion. In some species, however, there is a small, stellate famulus on tarsus I. This famulus is placed a small distance from the rhagidial organ in P. carinatus or laterally and far behind it in P. p o l o n i c u s. Strandmann (1971) also reported a famulus in P. a l a s k a e n s i s, accompanying the rhagidial organ. However, after repeated verification, he considered it is missing, particularly in specimens from Hawaii (Strandtmann & Goff 1978). Famuli are not known in other species.
oregonensis and P. t u r n e r i. Abbreviations: DD = dorsodistal; DM = dorsomedial; DP = dorsoproximal.
Penthalodes Tibia I Tibia II Tibia III Tibia IV
alaskaensis 2 DD in line: one in pit and 2 DD in line: one in pit and 1 DM, erect 1 DM, erect longer one piliform longer one piliform
carinatus 2 DD in line: one thicker 2 DD in line: one thicker 1 DM, erect 1 DM, erect baculiform (T) in pit and baculiform (T) in pit and
much longer one thin piliform slightly longer one thin
piliform
hawaiiensis 2 DD in line: one thicker rod- 2 DD in line: one thicker rod- 1 slender erect 1 slender erect like in pit and longer one thin like in pit and longer one thin
piliform piliform
ovalis sensu 2 DD in line: one longer rod- 2 DD in line: one slightly DP short baculiform DP slightly longer than
Kaluz (2000) like in pit and one thicker thicker and longer rod-like in that on Tb III sharply-tipped spiniform pit and one spiniform baculiform
ovalis sensu ????
Baker (1990)
polonicus 2 DD in line: one thicker 2 DD in line: one longer thick 1 DP erect baculiform 1 DP erect baculiform
banana-shaped in pit and banana-shaped in pit and one
shorter one baculiform rod-like
continued.
hawaiiensis 1 DM, erect piliform; plus 1 1 DD, erect piliform; plus 1 1 slender erect 1 slender erect tiny famulus at dorsal tiny famulus at dorsal
anterior margin anterior margin
ovalis sensu 1 DM, erect short spiniform 1 DM, erect short spiniform 1 DM erect baculiform 1 DD erect baculiform
Kaluz (2000)
ovalis sensu ?? distal papilla (Fig.13f)?
Baker (1990)
polonicus 1 distal large banana-shaped; 1 distal large banana-shaped; 1 distal banana-shaped 1 distal banana-shaped
plus 1 tiny bifurcate famulus plus 1 tiny spiniform
at dorsal anterior margin famulus at dorsal anterior
margin
The lateral solenidion on tarsus I is always very small and situated in a separate depression. In P. ovalis sensu Kaluz, it is rod-like (according to Kaluz, it is spiniform; see also Fig. 13c in Baker 1990) and is placed behind the rhagidial organ. In P. p o l o n i c u s, on the other hand, it is relatively large, T-shaped and is situated at the level of the proximal solenidion. Baker (1946) mentions the lateral solenidion (as a sensory seta) of the rhagidial organ in all species described by him; it is rod-like as other solenidia. A similar situation occurs in P. hawaiiensis. In P. carinatus, Shiba did not observe the solenidion of that type.
The two solenidia of rhagidial organ I can be in tandem in confluent depressions, like in P. alaskaensis and P. p o l o n i c u s, or in separate depressions, like in P. carinatus and P. ovalis sensu Kaluz. Solenidia are usually baculiform, except in P. ovalis sensu Kaluz, where they are lanceolate and sharply tipped; in P. carinatus they resemble the letter “T”; and in P. p o l o n i c u s a banana. In P. polonicus, the distal solenidion protrudes from the short depression; it is also characteristic that the distal depression is below the proximal one. The solenidia in P. o v a l i s sensu Baker (1990) are semi-erect because the depression, in which they are inserted, is short.
The three solenidia of rhagidial organ II can be arranged one behind another in confluent depressions, like in P. alaskaensis, P. boneti, P. h a w a i i e n s i s and P. polonicus. Otherwise, in P. o v a l i s sensu Kaluz two distal solenidia are parallel and situated in a common depression. P. c a r i n a t u s is similar, but has separate depressions. In P. hawaiiensis, the bases of the solenidia do not lie in one line but are staggered in tandem. In P. p o l o n i c u s, the solenidia are in one line but overlap each other because the depression is short resembling a cascade. In P. ovalis sensu Kaluz, two distal solenidia are baculiform, while the proximal solenidion is lanceolate. In P. carinatus, the solenidia slightly resembles the letter “T”. In P. hawaiiensis, they are baculiform and of different length and thickness; the proximal solenidion is the thickest and longest, while the distal one is the thinnest and shortest. In P. polonicus, differences between solenidia are slightly less visible; and laterally to rhagidial organ II lies a small, spiniform solenidion or famulus (?) in a pit, like in P. hawaiiensis. This structure resembles a solenidion because it is hollow (transparent) proximally, while being solid (non-transparent) distally like a famulus. In other species, this has not been observed.
The occurrence of solenidia on all tibiae and genua, plus single famuli on genu I and II near the distal margin of the article, is characteristic for Penthalodes. Famuli are not recorded in other descriptions, although Strandtmann (1971) observed tiny sensory setae and Baker (1990) mentioned a characteristic papilla on genu III. On tibiae I and II, the distal solenidion is situated in a depression, while the proximal solenidion is erect. Particularly large disproportions in the size of solenidia on tibia II occur in P. polonicus, where the distal solenidion is very thick, and at least by half as long as the tiny, rod-like proximal solenidion. In P. c a r i n a t u s, the proximal solenidia are erect, sharp-pointed and clearly longer than the distal solenidia, which are thicker, rather T-shaped, and pointed distally. P. hawaiiensis is similar, where the proximal solenidia are thin and longer than the rod-like, slightly thicker distal solenidia. In P. o v a l i s sensu Kaluz, on tibia I the distal solenidion is rod-like and slightly longer and thinner then the proximal solenidion; on tibia II, the proximal solenidion is short and piliform, while the distal solenidion is rod-like and slightly thicker and longer than the proximal solenidion. The bases of distal solenidia lie in a deep pit so that only the distal part is visible from the pit aperture. Solenidia on genua I and II in this species are very short and spiniform, contrary to P. polonicus where they are large, thick and banana-shaped. Solenidia on genua III and IV in P. ovalis sensu Kaluz are of similar length and thickness, contrary to P. polonicus where the solenidion on genu IV is thicker and longer than that on genu III. In both species, solenidia on tibiae III and IV are of subequal length and thickness. For other species, there are no detailed descriptions or drawings.
Leg setae are characteristic for Penthalodes. In P. polonicus, they are rather plumose and have a short shaft with triangular outgrowths, with the apical outgrowth being clearly the longest. At the base of each apotele are three pairs of thick setae, expanded distally, which are distinct in P. polonicus and P. h a w a i i e n s i s. In other species there is no information, although Strandtmann (1971) noted the occurrence of four pairs of apical setae on all tarsi (i.e. those lying close the apotele) as well as the occurrence of a single dorsal seta in the proximal part of the article as a characteristic feature of Penthalodes.
Aspidosoma. The aspidosoma is not separated from the rest of the body because the transverse "das" furrow is absent. In other eupodoids it usually separates the prodorsum from the opisthodorsum. The usually characteristic prodorsal plate of eupodoids is also absent. The ornamentation of the prodorsum is the same as the opisthodorsum. On the sides of prodorsum, more or less behind setae xa, the V-shaped furrows begin. All Penthalodes have a prodorsum with an anterior, steep wall of the aspidosoma, i.e. in fact of the idiosoma. Therefore, the naso lies frontally, more or less half-way up the anterior wall of the idiosoma. Setal pairs le and xa are also situated frontally. Setae le are well removed from setae bo, while setae xa lie laterally, slightly behind the line of setae le. Prodorsal setae bo lie as far back as between furrows “V”, in deep bothridia, rather dorsally. In P. polonicus, they are filiform (sensu Jesionowska 2002) in their distal part, while the proximal part is covered with tiny hairs. It is similar in P. hawaiiensis except they are weakly plumose in the distal part because they have more thickly placed outgrowths (pers. observations). The drawing from Strandtmann, however, seems to show they are filiform. In P. o v a l i s sensu Kaluz, they are spiculate distally. In P. c a r i n a t u s, they are apically pilose, like in the species described by Baker (1946). In P. sp. presented by Baker (1987), setae bo are strikingly short and rather filiform on their whole length. Therefore, most probably, setae bo in representatives of the genus Penthalodes are weakly plumose in their distal part (or spiculate, or pilose).
Eyes. Lentiform eyes have been observed in most representatives of Penthalodes. On the photograph published by Baker (1990), fine striation of their surface is seen. The eyes are situated behind setae xa, laterally, more or less at the level of where furrows “V” start.
Gnathosoma. The lack of a cheliceral seta is most probably characteristic for Penthalodes. The shape of the profile of the pedipalpal tarsus differs in some species. The tarsus can be elongated (P. alaskaensis, P. ovalis and P. polonicus) or shorter, similar to an oval (P. c a r i n a t u s). In P. a l a s k a e n s i s, P. c a r i n a t u s, P. hawaiiensis, P. ovalis and P. polonicus a small rod-like solenidion is recumbent in a depression. In P. hawaiiensis and P. polonicus, the tip of the three apical setae each on the pedipalpal tarsus is characteristic; they bear strongly sclerotized shuttles (carinas; Fig. 4 CD). According to Kaluz (2000), two apical setae are solenidia, while Strandtmann (1971) and Baker (1946) stated only that they are nude. For other species, sufficient descriptions and drawings are lacking. On the subcapitulum, a pair of setae n (sbc 2) lies more or less at the level of the labium, while setae m (sbc 1) lies laterally, antiaxially, at the base of the lateral lips fused in that part of subcapitulum with the hypostome. In P. hawaiiensis, they are rather plumose, in P. ovalis sensu Kaluz pilose, while in P. polonicus they are weakly plumose with rather long lateral outgrowths. The hypostome, which forms ventral part of subcapitulum, is composed of two parts, a basal rectangular and a distal triangular part. Usually, the inner sclerite is visible that separates these parts (Fig. 4 A; Fig. 5B in Strandtmann 1971).
description: Published as part of Jesionowska, Katarzyna, 2010, A morphological study of the genus Penthalodes (Acari, Prostigmata, Eupodoidea, Penthalodidae) with description of a new species, pp. 29-49 in Zootaxa 2672 on pages 32-48, DOI: 10.5281/zenodo.199162