Research Article |
Corresponding author: Ali Ahadiyat ( ali.ahadiyat@hotmail.com ) Academic editor: Farid Faraji
© 2016 Ali Ahadiyat, Frederic Beaulieu.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Ahadiyat A, Beaulieu F (2016) Two new mite species of the genus Zygoseius Berlese from Mexico (Acari, Mesostigmata). ZooKeys 629: 11-49. https://doi.org/10.3897/zookeys.629.10121
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Two new species of mites of the genus Zygoseius Berlese, Z. papaver sp. n. and Z. lindquisti sp. n., collected from moss and flood debris, respectively, in a creek in Chiapas State, Mexico, are described herein.
Gamasina , Pachylaelapidae , taxonomy, Chiapas, North America
The genus Zygoseius Berlese, 1916 is a moderately small genus of mesostigmatic mites, with 13 described species currently. It was first defined by
The taxonomic placement of Zygoseius is still problematic and authors placed it in various families: Ascidaesensu lato or Blattisociidae (
Mite specimens were collected from moss and debris in Chiapas State (officially the Free and Sovereign State of Chiapas), Mexico, in May 1969. All specimens had been extracted from samples using Berlese-Tullgren funnels, then cleared in lactophenol and mounted in Hoyer’s medium on microscope slides. Specimens were examined using a Zeiss Axio Imager M2 and a Leica DM 2500 compound scopes, attached to cameras AxioCam ICc 5 and ICC50 HD, respectively. Images and morphological measurements were taken via ZEN 2012 software (version 8.0) and Leica Application Suite (LAS) software (version 4.2, Live and Interactive Measurements modules). More than 120 morphological characters were examined and measured for each species. All the measurements were given as ranges of minimum–maximum, in micrometers (µm). Lengths of shields were taken along their midlines from the anterior to posterior margins; widths were measured approximately at mid-level (at the widest point) for the dorsal shield, between mid-level of coxae II (at the narrowest point) for the female sternal shield, and from the posterior part of coxae IV (at the widest point) for the male holoventral shield. Epigynal shield lengths were measured along their midlines from anterior margin of hyaline extension to posterior shield margin and also from the level of setae st5 to the posterior shield margin. Epigynal and ventrianal shield widths were measured at the widest point, past st5 level, and near ZV2 level, respectively. Leg lengths were measured ventromedially from the base of coxa to the apex of tarsus, excluding the ambulacrum (ambulacral stalk, claws and pulvillus); lengths of leg segments were taken dorsomedially. Ambulacra were measured ventromedially including pulvilli and claws. Setae lengths were measured from the bases of their insertions to their tips. Distances between setae were measured from the center of the setal alveolae. Corniculi were measured from the apex to the median section of posterior margins. Chelicera lengths were measured for: the first or basal segment, second segment (from base to apex of the fixed digit; width measured at the widest point), fixed digit (from dorsal poroid to apex) and movable digit (from base to apex). Length of peritreme was measured from the anterior margin of stigmata to the anterior end of peritreme. Length and width of anal opening were measured excluding the raised band of cuticle surrounding the anus. Idiosomal notation for setae used in this paper follows that of
(female). Dorsal shield oval, well-reticulated throughout, except nearly smooth medially between setae j6–J4; shield with serrated lateral margins. Dorsal setae smooth, relatively short, all <35 long, some podonotal (s3–5, z6) and opisthonotal (J1, J2, J4, Z1–4) setae longer than other setae; setae J5 strongly mesad, and slightly anterad Z5. Sternal shield irregularly and sparsely micropunctate, with a transverse, recurved linea posterad level of setae st1. Epigynal shield punctate, mostly anteriorly and laterally. Ventrianal shield wider than long, lineate except anterad anus, and punctate except in anterior fourth; setae JV1–2 1.5–2× as long as other setae on shield. Peritrematal shield micropunctate; punctae larger in poststigmatic region. Soft lateral and opisthogastric integument bearing nine pairs of short setae. Epistome bifurcate, distal haves of projections bipectinate. Hypostomal setae h1 twice as long as h2 and 1.5× as long as h3. Cheliceral movable digit with two subapical, unconspicuous teeth. Cheliceral fixed digit with two subapical teeth. Genua II–III with 10 and 8 setae, lacking setae av and pv, respectively. Spermathecal apparatus with globular spermatheca separated from small, ring-like sperm reservoir by a thick-walled, short duct; spermatic canal long, narrow.
Female (n = 11). Dorsal idiosoma (Figs
Lengths of most idiosomal setae of Zygoseius papaver sp. n. and Z. lindquisti sp. n.
Setae | Z. papaver | Z. lindquisti | |
---|---|---|---|
Female (n = 11) | Male (n = 1) | Female (n = 2) | |
j1 | 10–15 | ? | ~ 5–7 |
j2 | 17–25 | ? | 14–17 |
j3 | 19–27 | 24 | 15–17 |
j4 | 18–25 | 21 | 16–19 |
j5 | 16–20 | ~ 15 | 14–17 |
j6 | 16–20 | 17 | 16–20 |
J1 | 26–30 | 24 | 27–32 |
J2 | 24–32 | 26 | 28–34 |
J4 | 24–30 | 22–24 | 30–31 |
J5 | 16–22 | 17–19 | 19–21 |
z1 | 9–12 | ? | ~ 5–7 |
z2 | 17–21 | ~ 12 | 13–18 |
z3 | 17–25 | ~ 20 | 17–19 |
z4 | 19–31 | 22 | 15–19 |
z5 | 16–23 | 16 | 15–19 |
z6 | 24–32 | 30 | 26–34 |
Z1 | 22–29 | 27 | 30–31 |
Z2 | 25–30 | 26 | 33–34 |
Z3 | 23–28 | 22 | 31–33 |
Z4 | 22–28 | 22 | 30–31 |
Z5 | 15–22 | 16 | 20–26 |
s1 | 12–17 | ~ 11 | 14–19 |
s2 | 19–26 | ? | 17–22 |
s3 | 21–28 | 22 | 19–21 |
s4 | 22–27 | 25 | 18–21 |
s5 | 23–30 | 25 | 22–24 |
s6 | 19–22 | 18 | 28–29 |
S1 | 18–24 | ? | 27–31 |
S2 | 17–23 | 18 | 29–32 |
S3 | 16–21 | ~ 16 | 26–30 |
S4 | 16–22 | 19 | 27–31 |
S5 | 16–21 | 17 | 28–31 |
r2 | 12–20 | ~ 16 | 19–20 |
r3 | 14–17 | 15 | 19–21 |
r4 | 18–20 | 21 | 20–21 |
r5 | 17–20 | ? | 22–25 |
r6 | 19–20 | ~ 20 | 24–29 |
st1 | 16–21 | 18 | 16–20 |
st2 | 17–23 | 16 | 20–23 |
st3 | 17–22 | 18 | 18–21 |
st4 | 15–20 | 13 | 16–19 |
st5 | 18–24 | 14 | 18–19 |
JV1 | 25–32 | 25–27 | 19–23 |
JV2 | 26–34 | 28–30 | 22–25 |
JV3 | 16–22 | 17–18 | 16–19 |
JV4 | 13–17 | 13–14 | 20–21 |
JV5 | 14–18 | 14–15 | 18–19 |
ZV1 | 12–18 | 10–14 | 15–16 |
ZV2 | 11–17 | 12 | 18–21 |
ZV3 | 14–17 | 13–15 | 18–21 |
Para-anal setae (pa) | 18–22 | 18 | 21–24 |
Post-anal seta (po) | 17–23 | 16 | 20–22 |
Distances between pairs of some dorsal and ventral idiosomal setae of Zygoseius papaver sp. n. and Z. lindquisti sp. n.
Characters | Z. papaver | Z. lindquisti | |
---|---|---|---|
Female | Male | Female | |
st1–st1 | 31–41 | 37 | 41–48 |
st2–st2 | 43–47 | 41 | 50–53 |
st3–st3 | 39–45 | 45 | 50–54 |
st4–st4 | 51–57 | 37 | 61–63 |
st5–st5 | 55–62 | 39 | 62–65 |
J1–J1 | 37–49 | 31 | 52–58 |
J4–J4 | 63–80 | 61 | 81–83 |
J4–J4/J1–J1 | 1.38–1.72 | 1.96 | 1.42–1.57 |
J2–J2 | 34–47 | 38 | 45–47 |
J1–J2 | 26–35 | 31 | 36–41 |
Ventral idiosoma (Figs
Gnathosoma. Epistome (Fig.
Legs (Figs
Spermathecal apparatus (Plate
Male (n = 1). Dorsal idiosoma (Fig.
Ventral idiosoma (Fig.
Gnathosoma. Epistome as in female, with two projections, 19 long, distance between bases of projections 5. Corniculi (26 long) and deutosternum as in female. Lengths of hypostomal setae: h1 39, h2 14, h3 24, pc 19. Chelicera and spermatodactyl not available for study (broken off specimen). Palp 98 long, similar to that of female; trochanter 13 long, femur 40, genu 22, tibia about 21; palp setae and chaetotaxy as in female.
Legs. Lengths of legs: I 288, II 239, III 231, IV 288. Lengths of femora: I 61, II 44, III 55, IV 60; genua: I 45, II 37, III 26, IV 30; tibiae: I 44, II 32, III 25, IV 31; tarsi: I 61, II 71, III 68, IV 87, ambulacra: I 18, II 20, III 19, IV 24. Chaetotaxy of legs I–IV similar to that of female, except that the femur II has one conical spine-like projection ventrodistally (Fig.
Unknown.
Holotype: Female. Mexico, Chiapas State, Volcan Tzontehuitz, 9000 ft. (= 2743.2 m. a.s.l.), 12 miles NE of San Cristóbal de Las Casas, from moss on log, 19 May 1969, coll. J. M. Campbell. Paratypes: 15 females, 1 male, same data as holotype. The holotype and 12 paratypes (females and male) are deposited at the Canadian National Collection of Insects, Arachnids and Nematodes (
The specific name refers to the shape of the spermatheca of the new species, which resembles the capsule of opium (Papaver somniferum L., 1753). It is considered as a noun in apposition.
The spermathecal apparatus of Z. papaver sp. n. is distinct from that of any other Zygoseius species for which it was described: the spermetheca is globular and larger than any other sclerotized part of the apparatus, and ends in a flower-like pattern. The new species can also be distinguished by its long J1–2 setae relative to the distance between J1 and J2 setae (ratio setal length/distance = 0.90 ± 0.06 st.dev., range 0.75–1.0). Based on their illustrations, a few species described from South America have long J1–2 setae relative to the distance between them, such as Z. alveolaris Karg, 1998 and Z. triramuli Karg & Schorlemmer, 2009 (
The epistome of Zygoseius papaver sp. n. is unique among described species, with relatively short but thick projections that are conspicuously barbed apically. The epistome of Z. laticuspidis Karg, 1998 is similar; however, it is even more swollen apically, and is slightly denticulate on the basal margin in-between the projections. Zygoseius laticuspidis also has J5 setae inserted mesad of Z5 (note, however, that the relative position of J5 and Z5 can vary, depending on how flattened is the dorsal shield on the slide). The new species can further be distinguished from Z. laticuspidis by its shorter dorsal setae (all are <30 long; most are 30–60 long in Z. laticuspidis), J4 setae separated by 1.4–1.9× the distance between J1 setae (J4–J4 distance over twice that between J1–J1 in Z. laticuspidis), and by the presence of nine pairs of setae on the opisthogastric soft cuticle (six pairs in Z. laticuspidis). Other Zygoseius species can be distinguished from Z. papaver sp. n. by some of the same characters mentioned above, as well as by (1) its epistome; (2) the length and width (and their ratios) of the dorsal, sternal and ventrianal shields; (3) relative length of dorsal setae, especially Z5; (4) the ornamentation of the dorsal and sternal shields; and (5) long JV1–2 setae, 1.5–2× as long as other pre-anal setae on the ventrianal shield, and as long as about 2/3 of distance between JV1 and JV2. Zygoseiusampullus Halliday, 1997 and Z. foramenis Karg, 1998 also have longer JV1–2 setae but clearly differ by their epistomes, and by shorter J1–2 setae and a ventrianal shield as long as wide. In the key to species of
Another distinguishing feature of Z. papaver sp. n. is the distinctly serrated lateral margins of the dorsal shield. This also characterizes Z. ovatus Karg, 1998. The margins of the dorsal shield of other species may appear somewhat serrated (e.g. Z. ampullus, Z. metoecus Halliday, 1997 and Z. separatoporus Karg, 1998), although the serration matches with the insertion of setae in marginal positions (mostly r and S setae), whereas in the new species and at least in Z. ovatus, most serration are independent of setal insertions. Such serrated margins of the dorsal shield are reminiscent of the dorsal shield of many Zerconidae (
Zygoseius papaver sp. n. also differs from other Zygoseius species by its reduced chaetotaxy on genu II, lacking seta av, and genu III, lacking seta pv, instead of the usual complement of two ventral setae, including both av and pv as noted in the genus diagnosis of
Dorsal shield oval, densely micropunctate, with relatively distinct reticulation and lineation, except more weakly reticulated medially between setae j4–6. Edges of lateral parts of dorsum smooth. Dorsal setae smooth, except J4 and J5 with a few barbs basally; all setae less than 35 long; setae z6, s6, and all opisthonotal setae (except J5 and Z5) 1.5–2× as long as other setae. Sternal shield densely micropunctate, except in the regions of setal insertions. Epigynal shield conspicuously punctate in anterior 2/3, punctae lighter posteriorly. Ventrianal shield distinctly lineate in anterior half, reticulate laterally and posteriorly; setae JV2 slightly longer than other setae on shield. Peritrematal shield micropunctate throughout, punctae larger in poststigmatic region. Soft lateral and opisthogastric cuticle with nine pairs of setae. Epistome bifurcate, thin projections slightly converging, about twice as long as distance between their bases, sparsely serrated in apical half. Hypostomal setae h1 about twice as long as h2, and subequal to h3. Femur I with seta pd2 thickened. Spermathecal apparatus with a small, kidney-shaped spermatheca directly connected to a globular, large sperm reservoir, followed by a long spermatic canal with diverging walls.
Female (n = 2). Dorsal idiosoma (Figs
Ventral idiosoma (Figs
Gnathosoma. Epistome (Fig.
Legs (Figs
Spermathecal apparatus (Plate
Unknown.
Holotype: Female. Mexico, Chiapas State, 6 miles NE of San Cristóbal de Las Casas, from flood debris in creek, 15 May 1969, coll. Evert E. Lindquist. Paratype: Female, same data as holotype. The holotype and paratype are deposited at the Canadian National Collection of Insects, Arachnids and Nematodes (
The species is named in honor of Evert E. Lindquist, for his invaluable endeavors on the systematics of Mesostigmata over the years. The specimens of this new species were collected by him.
The dorsal seta of trochanter I in Z. papaver and Z. lindquisti is inserted in a posterior position. We herein call this seta d (Figs
In his diagnosis of the genus Zygoseius,
In addition to poroid idR3, between setae R3 and R4, the soft opisthogastric cuticle has a sclerotized complex of two pore-like structures, posterolaterad the peritrematal-metapodal shield. These structures may be two openings of the same underlying gland complex; alternatively, they may be a gland opening and an associated poroid (note that both of these structures are sometimes visible in lateral view when the soft cuticle is folded, instead of the normal ventral view). It is unclear whether this gland opening is homologous to the one (gp) typically found in the poststigmatic region of peritrematal shields in many Mesostigmata (e.g.
Zygoseius lindquisti sp. n. shares certain morphological features with Z. incisus Karg, 1998 and Z. margaritatus Karg & Schorlemmer, 2009, including: (1) an epistome with two thin projections, about twice as long as distance between their bases, sparsely serrated, mostly in apical half; (2) the ratio J4 setae inserted well farther apart from each other than J1 setae (ratio of distance J4–J4/J1–J1= 1.42–1.57 in Z. lindquisti sp. n.); (3) J1–2 setae slightly shorter than distance between insertions of J1 and J2 (length J1–2 setae/J1–2 distance= 0.8–0.9 in Z. lindquisti sp. n.); (4) ventrianal shield with short setae, including JV1–2; (5) the length of seta Z5 (20–26 in Z. lindquisti sp. n.). It also has a spermathecal apparatus similar to Z. margaritatus, although the latter has a more elongate, egg-shaped spermatic reservoir followed by a spermatic canal more constricted distally. The spermathecal apparatus of Z. incisus is distinct, with a narrow elongate spermatic canal. The species Zygoseius lindquisti sp. n. can further be distinguished from the two species by (1) the dense micropunctation on its dorsal, sternal and genital shields, and its ventrianal shield lineate anteriorly and reticulate laterally and posteriorly; (2) its relatively broad dorsal shield (396–413 long, 278–283 wide; vs 430 long, 260 wide in Z. incisus, 336–392 long, 231–256 wide in Z. margaritatus); (3) its relatively wide ventrianal shield (153–154 long, 189–196 wide; vs. 160 long, 170 wide in Z. incisus, 140 long, 182 wide in Z. margaritatus); (4) many longer setae in the opisthonotal region (e.g. J1, J4, S5).
The new species also has a spermathecal apparatus similar to Z. furciger. Based on the two females examined, however, Z. lindquisti sp. n. has a sperm reservoir globular with enlarged spermatic canal throughout, whereas the sperm reservoir of Z. furciger ranges from globular to oval with spermatic canal constricted distally (in proximity to sperm reservoir). The detailed description of
The record of a “Zygoseius sp.” by
Some morphological characters are of particular interest for the diagnosis of Zygoseius species and possibly also for classifying them into species groups. Perhaps the most useful character to distinguish Zygoseius species is the spermatheca itself varying in size relative to the rest of the apparatus, and the sperm reservoir varying in shape, ranging from oval to globular (
The dorsal idiosomal chaetotaxy is moderately useful, with some setae varying markedly in position between species, such as J5 relative to Z5, and with the atypical presence of seta J3 in some species (in Z. triramuli and Z. alveolaris;
The epistome and the male chelicerae appear as the most studied (or most often illustrated) gnathosomal characters in Zygoseius. There is some interspecific variation in the epistome, including the number (usually 2, rarely 3 or 4) and length of projections, and the extent of barbs on the margins. These variations are overall only moderate, although overall represent useful diagnostic features. Male chelicerae may be useful, with some apparent variation in dentition and in the lengths of spermatodactyls (e.g. Z. furciger has a longer spermatodactyl relative to cheliceral digits;
This study was supported by a sabbatical grant to the senior author (AA) (No. 9/S/70/98512) for visiting the Canadian National Collection (