Neoseiulus californicus ( McGregor, 1954 ) sensu Athias-Henriot (1977)

Beaulieu, Frédéric & Beard, Jennifer J., 2018, Acarine biocontrol agents Neoseiulus californicus sensu Athias-Henriot (1977) and N. barkeri Hughes (Mesostigmata: Phytoseiidae) redescribed, their synonymies assessed, and the identity of N. californicus (McGregor) clarified based on examination of types, Zootaxa 4500 (4), pp. 451-507 : 488-495

publication ID

https://doi.org/ 10.11646/zootaxa.4500.4.1

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lsid:zoobank.org:pub:16A34E21-D55D-40E9-BF2D-43D3BD8A6AF2

persistent identifier

https://treatment.plazi.org/id/03E987BF-FFEE-FFDF-FF44-FD3CFAE3E443

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Felipe

scientific name

Neoseiulus californicus ( McGregor, 1954 ) sensu Athias-Henriot (1977)
status

 

Neoseiulus californicus ( McGregor, 1954) sensu Athias-Henriot (1977) View in CoL

( Figures 20, 22, 24 View FIGURES 19–24 , 29–44 View FIGURES 29–35 View FIGURES 36–41 View FIGURE 42 View FIGURES 43–44 ; Table 3)

Typhlodromus chilenensis Dosse, 1958b: 55 . (types examined)

Cydnodromus californicus .— Athias-Henriot, 1977: 61.

Amblyseius wearnei Schicha, 1987: 103 . (specimens matching type data examined)

Diagnosis (of adult male and female, unless otherwise stated). Dorsal shield reticulate throughout; shield elongate, 1.80–2.15x as long as wide in female, 1.57–1.81 in male; female shield gradually widening from level of setae s4 to S2, shield margin weakly and irregularly concave at level of R3; setae Z1 and S2 close to shield margin in female (12–19 and 5–12 from it); seta R1 on dorsal shield margin in male; dorsal setae relatively long, Z4–5 elongate (45– 61 and 62–83 in female, respectively), with numerous barbs; j1 bases almost contiguous, their paraxial edges separated by distance subequal to width of a base; gland openings gd1, gd6, gd9 visible on dorsal shield; gland opening gd4 absent; gd3 conspicuous on shield margin in male (posterolateral to s4), inconspicuous on peritrematal shield in female; gd1 slightly to moderately anterolaterad of an imaginary line connecting j3 - z2; gd9 distant to, and mesal to seta S5. Female with poroids is1 and idl1 on shield margin (rarely on soft cuticle). Sternal shields reticulate; female with st3 inserted on sternal shield. Ventrianal shield with three pairs of pre-anal setae (JV1–2, ZV2) in both male and female; shield well-reticulated, with well-defined cells including region lateral to the anal opening; female shield usually constricted at level of JV2, or clearly narrower at JV2 level vs. ZV2 level. Female with four setae (ZV1, ZV3, JV4–5) on soft opisthogastric cuticle, male only with JV5. Gland openings gv3 conspicuous and broad, mesal to JV2 and slightly posterior to level of JV2, with gv3–gv3 distance 0.29–0.46 x JV2–JV2 distance. Postanal seta (17–25 in female) longer than para-anal setae (14–18 in female), of similar length to or slightly longer than pre-anal setae (15–25 in female). Movable cheliceral digit of female with 3 teeth, fixed digit with 4–5 (rarely 6) total teeth, with 2 subapical teeth (offset on antiaxial margin of digit) followed by 2–3 teeth (rarely 4) (aligned along paraxial margin of digit), usually including 2 teeth (one regular, one minute) proximal to pilus dentilis and well separated from other teeth. Spermatodactyl U-shaped. Calyx of spermathecal apparatus variously bell-shaped, usually slightly shorter than broad (7–15 long, 8–18 wide distally), with calyx walls varying from clearly diverging to almost parallel; atrium simple, undifferentiated, nodular. Leg IV with a single macroseta on basitarsus (pd3), 47–58 in female.

Material examined. See Table 1. All the material used in this description has been determined as N. californicus sensu Athias-Henriot by us or previous authors (slide lots # 20–46) and includes: type material of N. chilenensis (lot #43), specimens previously identified as N. chilenensis (lots #44–46), and specimens that match or closely match the collection data of the type of N. wearnei (lots #40–42).

Redescription. Female (n=99). Dorsal idiosoma ( Fig. 36 View FIGURES 36–41 ; Table 3). Dorsal shield 340–406 (318–384 between j1–J5) long x 168–216 wide (near S2 level; 137–188 at s4 level), elongate, shield width gradually increasing to its widest point just anterior to setae S2, shield margins slightly concave at level of R1; shield reticulate throughout; shield with 17 pairs of moderately long, mostly smooth setae: j1 (20–26), j3 (26–38), j4–j5 (18–30), j6 (24–36), J2 (28–41), J5 (11–16), z2 and z4 (24–37), z5 (21–29), Z1 (24–42), s4 (29–44), S2 (33–47), S4 (30–45), S5 (26–39); Z4 (45–61) and Z5 (62–83) elongate, with numerous barbs; clunal seta (J5) usually with 1–2 barbs basally (see Xu et al., 2013). Setae r3 (23–30) and R1 (20–28) on soft cuticle lateral to shield. A total of 16 pairs of poroids and three pairs of gland pores (gd1, gd6, gd9) visible on shield (rarely poroids is1 or idl1 on soft cuticle) (pores gd2, gd4, gd5 and gd8 absent or not discernible); poroid idm2 clearly anterior to level of seta J2; poroid idm1 aligned with gland pore gd6 and seta Z1 or (slightly to moderately) mesad to gd6-Z1 alignment; one poroid (idR3) on soft cuticle at a level anteriad of S4. Peritrematal shield fused to dorsal shield at level anteriad of j3 and lateral to j1; peritremes narrow (4–6 wide), extending forward to near bases of j1.

Ventral idiosoma ( Figs 37, 40–41 View FIGURES 36–41 ; Table 3). Tritosternum with plumose laciniae 64–76, including a fused proximal section 23–36 long (laciniae delimited from columnar base (12–21 long) by transverse line). Sternal shield 64–74 wide, reticulate throughout except smooth or punctate posteromarginally, where often overlapped by anterior margin of epigynal shield; mesal cells in reticulation smaller; anterior shield margin poorly defined, with adjacent presternal area lightly sclerotised, with a few transversal lineae; lateral margin of shield not acutely produced at level between coxae II–III, projection truncate, rounded or eroded, setae st1–5 smooth; setae st1–3 (25–34) on shield; st4 (27–32) and poroid iv3 inserted on irregularly suboval metasternal platelet. Epigynal shield truncate and widest posteriorly, narrowed at level anteriad of setae st5 (24–32); shield smooth posteromedially, reticulate anterolaterally. Ventrianal shield 110–137 long, relatively broad anteriorly (94–119), lateral margins slightly concave (or at least shield narrowed) at level of JV2 setae, and at level anteriad of postanal seta; shield bearing three pairs of moderately short (15–25), smooth pre-anal setae (JV1–2, ZV2); shield reticulate throughout, reticulation weaker surrounding anal opening; pair of gland openings gv3, broad, conspicuous, slightly crescentshaped, moderately close to each other (20.1 ±1.7;15–25), 13–22 µm mesal to and 6–13 posterior to setae JV2; pair of short narrow platelets (representing a sigilla; sgpa in Tsolakis & Ragusa 2016), one near each anterolateral corner of ventrianal shield; cribrum with 3–4 irregular rows of spicules; postanal seta (17–25) longer than para-anal setae (14–18), which are inserted level with one third of anal opening length from anterior margin of anal valves. Peritrematal shield a narrow band of cuticle bordering peritreme laterodorsally; band interrupted in the region of r3; shield bearing one poroid (id3) and one gland opening (gd3) near level between coxae II–III, poststigmatic region of shield bearing two poroids and one gland opening, and merged with exopodal-parapodal elements partly, surrounding coxa IV posteriorly, bearing gland opening gv2. Endopodal elements between coxae I–II weakly developed, sometimes free, sometimes fused to anterolateral corners of sternal shield; narrow endopodal strip mesal to coxa IV. Narrow exopodal strip near coxae II–IV, narrowly joining peritrematal shield posteriorly, at level of mid-point of coxa IV. Soft opisthogastric cuticle with: four pairs of smooth setae, ZV1 (21–29), ZV3 (13–19), JV4 (15–20, exceptionally 29), and JV5 elongate (44–64); two pairs of narrow metapodal platelets, primary (outer) metapodal long (22–37), at level of ZV1, secondary metapodal straight or crescent-shaped; six pairs of poroids, including iv5 (between st5 and ZV1), ivp (mesal to JV5), and ivo (four).

Spermatheca ( Fig. 42 View FIGURE 42 ). Calyx of spermathecal apparatus variously bell-shaped, with length (7–15) greater, lesser, or subequal to distal width (8–18). Atrium nodular, 1.5–2.2 µm long and 1.6–1.7 µm wide, narrowing into major duct of ca. 0.5–1.0 µm in diameter, running for ca. 20 µm, expanded to ca. 2 µm in diameter for the proximal 3 µm of duct, before solenostome at level between coxae III and IV. Minor duct slightly finer than major duct, ca. 0.5–0.7 µm diameter, of undetermined length.

Gnathosoma ( Figs 20, 22 View FIGURES 19–24 , 38–39 View FIGURES 36–41 ). Gnathotectum narrow, irregularly convex, with smooth margin. Corniculi horn-like, aligned parallel to each other, and close together with bases of inner margins (level with bases of internal malae) separated by 3–6; entire corniculi length 30–35 (from most proximal point visible internally). Internal malae hyaline, close to each other, tapered apically, lightly fringed, reaching tips of corniculi. Labrum broad basally, tapering to a point, reaching slightly beyond tips of corniculi. Hypostomal and capitular setae smooth, h1– h3 (18–26), pc (24–29). Deutosternal groove with seven rows of two denticles each, denticles set near lateral margins of groove; two basal rows close to each other; smooth ridge anteriorly at level of h3. First cheliceral segment 21–32 long, second segment including fixed digit 67–77 long; fixed digit 23–26 long, with 4–5 (rarely 6) small teeth, including (from distal to proximal) two subapical teeth (offset; aligned with pilus dentilis on antiaxial margin of digit), followed by 2–3 basal teeth, two of which (one minute, one regular) are well-separated from a more distal tooth; rarely a fourth tooth in the middle, near level of pilus dentilis. Movable cheliceral digit 26–31 long, with three teeth; dorsal cheliceral seta short and setiform; dorsal and lateral (antiaxial) poroid (lyrifissure) present; arthrodial membrane of movable digit a simple corona. Palp chaetotaxy, including shape of modified setae on palpfemur–palptarsus as for N. barkeri (see above); palp apotele 2-tined.

Legs ( Figs 43–44 View FIGURES 43–44 ). All legs with ambulacrum, including well-developed stalk, claws and pulvillus; ambulacrum of leg IV longer (24–31) than those of legs I (16–20) and legs II–III (21–25). Chaetotaxy of leg as in N. barkeri (see above); exceptionally, two females with genu IV with eight setae instead of seven, including an additional pl seta in distal half of segment (1–2/1, 2/0–2). Tarsi II-III-IV 18-18-18, with ad1–pd1 as inconspicuous, short (3.5–5) apical processes; all leg setae simple, slender, moderately long (11–27) except shortened setae on femora I–II: al1 (8–10), al2 (4–7), ad2 (7–10), ad3 (5–8), and femur III–IV: pd (6–11), pl (5–9). Tarsal setae longest, especially ad2, pd2 (20–30) and pd3 (StIV; 47–58) on basitarsus IV. Setae ad1 on genu IV (18–26) and tibia IV (21–33) only slightly longer and thicker than surrounding setae (regarded here as weakly differentiated macrosetae). Tarsus I with 36 tactile setae (18–34 long), and apicodorsal cluster of short, chemosensory setae. Coxa I bearing two gland openings (gc) ventrally, each connected to several glands with internal calyces.

Male (n=34). Similar in chaetotaxy, adenotaxy and poroidotaxy to female except as indicated below. Idiosomal setae are 71–94% length of those of female (average across males / average across females) (Table 3; as a comparative reference: male dorsal shield is on average 79% the length of female dorsal shield).

Dorsal idiosoma ( Figs 29, 31 View FIGURES 29–35 ; Table 3). Dorsal shield 265–316 long x 151–189 wide; setae r3 and R1 captured by dorsal shield. Shield more or less parallel-sided from level of setae r3 to posteriad of S2, and peritrematal shield fused to dorsal shield from level of r3; shield reticulate throughout; Z4 (38–51) and Z5 (48–61) moderately long, with numerous barbs, other setae smooth. Gland openings gd3 conspicuous, somewhat triangular or tent-shaped, on shield margin posterolateral to setae s4; gd4 absent; remaining dorsal adenotaxy and poroidotaxy similar to that of female. Peritremes extending forward to just anterolaterad of bases of j3.

Ventral idiosoma ( Figs 30, 32–34 View FIGURES 29–35 ; Table 3). Sternogenital shield 111–131 long, essentially reticulate, except smooth in anteromedial region; cells of reticulation slightly narrower posterolaterally (posterior to setae st4); reticulation in posteromesal region weakly developed, enclosed within an inverted V-shape indicated in the cuticle (partly circumscribed by sigillae); shield widest (67–84) at level of fusion with endopodal elements between coxae II–III, or at level of (long narrow) endopodal elements between coxae I–II when those are not broken off shield; shield bearing smooth setae st1–5 (17–23) and poroids iv1–3, and iv5 (not always discernible); posterior margin straight, usually eroded between endopodal element and region of st5; presternal area weakly sclerotised, faintly lineate, as in female. Ventrianal shield abutting sternogenital shield; shield 105–122 long, relatively broad anteriorly (138–170), lateral margins more or less convex, bearing three pairs of relatively short (14–18) pre-anal setae (JV1–2, ZV2), and four pairs of poroids (iv5, 3 ivo); shield reticulate throughout; pair of gland openings gv3, similar to that of female; postanal seta (14–21) longer than para-anal setae (12–16), which are inserted slightly anterior to mid-point of anal opening. Peritrematal, endopodal, exopodal and parapodal elements similar to that of female, except that parapodal elements sometimes abutting or narrowly fused to ventrianal shield medially. Soft opisthogastric cuticle with JV5 (30–44) posterolateral to shield, and three poroids (idR3, ivo, ivp).

Gnathosoma ( Figs 24 View FIGURES 19–24 , 35 View FIGURES 29–35 ; Table 3). Similar to that of females except the following: corniculi aligned at a convergent angle, and approximately three times more distant from each other than in female, with bases of inner margin separated by 14–18; entire corniculi length 21–25. Internal malae similar to those of female; a pair of distinct, apically pointed hyaline lobes present between each internal mala and corniculus ( Fig. 24 View FIGURES 19–24 , ‘lo’; absent in female), less than half the length of the mala. Anterior hypostome (anterior to deutosternum) more contracted than that of female, so that bases of corniculi (externally) and of internal malae much closer to level of h2–3 setae, and that h1 seta much closer to h3 setae than in female. Fixed cheliceral digit 19–21 long, with three small teeth, including (from distal to proximal) one subapical tooth (offset; on antiaxial margin), two proximal teeth of variable size, aligned along paraxial margin; setiform pilus dentilis proximal to teeth. Movable cheliceral digit 20–23 with a single tooth, and spermatodactyl shallow U-shaped to weakly L-shaped, shaft 15–17 (heel projecting along same axis as shaft, included in shaft length), foot (7–9) curved to form shallow U-shape, with small bulbous toe, bearing short blunt lateral projection on paraxial margin.

Legs. Leg segment chaetotaxy as in female, except setae slightly shorter than respective setae of female. Macroseta on basistarsus IV (StIV) 39–46.

Remarks. It is now clear that Nc -AH is not N. californicus , as described by McGregor (1954) as a male, or N. mungeri described as a female. Both N. californicus and N. mungeri represent the same species as N. barkeri Hughes (1948) , an older name. Later sections below discuss options for an appropriate name to use for Nc -AH.

Intraspecific variation. Xu et al. (2013) found a few character states in specimens of Nc -AH from southern China that distinguish them from specimens from elsewhere in the world. Griffiths (2015) concluded that the Chinese population ( Xu et al., 2013) represents a taxon morphologically close to Nc -AH, but that due to the presence of morphological variation, a decision on conspecificity was not possible until further studies were made. The most striking distinction of the Chinese population may be the narrower or more elongate calyx of its spermathecal apparatus, with lengths of 11–13 µm (based on our measurements made on their photos, Fig. 10A, B View FIGURES 10–11 ) and distal widths of 10–12 µm. The non-Chinese populations that they studied showed calyces of 8–11.5 long x 10.5–15 wide (based on their photos, Figs 10C–I View FIGURES 10–11 ); note the partial overlap in the calyx dimensions between the Chinese vs non-Chinese specimens, mostly the width. We have also observed quite a range of shapes and dimensions in the calyx (7–15 long x 8–18 wide), even more so than that indicated by the measurements just above. In fact, the range in variation observed—from narrow, elongate calyces to broad, shorter calyces, and with intermediate forms in between—was just as broad amongst specimens from within the same populations ( Figs 42e–f, m–o, p–q, r–s, t–u View FIGURE 42 ; and within a single individual) as it was between specimens from different populations. The calyx is certainly flexible in shape, especially when the accommodation of one or multiple spermatophores forces the calyx to expand or distort (e.g. Figs 42a, f, i, t, w View FIGURE 42 ). A calyx may remain, at least partly, expanded even after the spermatophore(s) has been utilised and absorbed, thereby affecting its dimensions and our measurements. The calyx may also present a different form depending on its position in the three-dimensional space, if it does not always assume a radially symmetrical shape, such that it may be more parallel-sided, or more conical, in one view but less so in another. The strongly triangular shape of some calyces, which we observed on either or both sides within a few individuals, seems to represent an exceptional extreme ( Figs 42s, u View FIGURE 42 ). An additional factor is the effect that the process of slide mounting can have on the shape of a calyx. For example, the average width of the calyx can increase up to 49% in specimens of N. californicus flattened on a slide vs specimens mounted with supporting threads that prevent pressure from the coverslip ( Jolly et al., 2001). Considerable intraspecific variation in the shape and dimensions of the calyx of Nc -AH has also been observed by previous authors ( Ehara & Amano, 2004; Jung et al., 2006; Tixier et al., 2008; Seyedizadeh et al., 2017).

The Chinese specimens studied by Xu et al. (2013) also differed by the pair of gv3 gland openings being farther apart from each other than those of other populations. More specifically, they found that in Chinese female specimens, the distance between the paraxial edges of the gv3 gland openings is about three times the width of the gland openings themselves, whereas in overseas specimens, the same distance is about two times the width of the gland openings. We examined this in our specimens (n=40) and we found that the ratio of the distance between the paraxial edges of the gv3 openings / gv3 width varies similarly between populations from Canada (1.8–2.8, n=8), California (2.2–3.0, n=10), Kenya (1.7–2.9, n=5), Australia (2.1–2.7, n=6), South Korea (2.1–3.5, n=5), and Chile (1.6–2.7, n=6). Averages are also similar, with Chile showing the lowest average ratio (2.1 ±0.4), and South Korea had the highest (2.6 ±0.6). To explore this further, we used the figures of Xu et al. (2013) to measure the distance between the gv3 openings from the centre of the gland openings (and used the scale shown to calculate the actual distance in µm): the Chinese specimen ( Fig. 11A View FIGURES 10–11 , Xu et al., 2013) had its gv3 openings 23 µm apart (and 25 µm, based on line-drawing illustration, Fig. 4 View FIGURES 4–8 ), and non-Chinese specimens had gv3 16–21 µm apart, except the Japan specimen which had gv3 25 µm apart. We have noted a similar range of variation in specimens we examined: 15– 25 µm between gv3, with some populations showing gv3 slightly farther apart (averages for South Korea: 21.1 ±0.9, Australia: 21.6 ±1.4) than others ( Chile: 18.7 ±2.9, Canada: 19.3 ±1.0, Kenya: 19.6 ±0.6, California: 20.6 ±1.0), but the overall ranges of distances largely overlap between populations. Similar results were obtained when gv3–gv3 distance values were divided by the width of the ventrianal shield (to control for any body size effect).

Xu et al. (2013) found that setae Z4 of specimens from China were smooth for the proximal quarter to third of their length, whereas Z4 of specimens from elsewhere were smooth for the proximal half of their length. We found that setae Z4, across specimens we examined, exhibited the range of variation observed by Xu et al., and were smooth for the proximal 28–53% of their length (n=40; the smooth portion measured as distance between setal base and the base of the first barb observed). Specimens from eastern Canada appear to have setae Z4 that are, on average, slightly smoother proximally (44.8% ±4.6, 37–53, n=9) than specimens from California (42.0% ±4.0, 36– 50, n=9), South Korea (38.6% ±9.6, 29–49, n=5), Chile (37.4% ±10.2, 25–49, n=3), eastern Australia (35.8% ±3.8, 30–43, n=9, including N. wearnei ), and Kenya (34.8% ±3.2, 28–41, n=5). Note that ranges broadly overlap between populations. Future research using morphology and molecular markers may test further the relatively well-supported hypothesis (e.g. Tixier et al., 2008; Tixier et al., 2014; Xu et al., 2013; Lv et al., 2016; this paper) that the observed morphological discrepancies represent intraspecific variation within a single species.

Kingdom

Animalia

Phylum

Arthropoda

Class

Arachnida

Order

Mesostigmata

Family

Phytoseiidae

Genus

Neoseiulus

Loc

Neoseiulus californicus ( McGregor, 1954 ) sensu Athias-Henriot (1977)

Beaulieu, Frédéric & Beard, Jennifer J. 2018
2018
Loc

Amblyseius wearnei

Schicha, E. 1987: 103
1987
Loc

Cydnodromus californicus

Athias-Henriot, C. 1977: 61
1977
Loc

Typhlodromus chilenensis

Dosse, G. 1958: 55
1958
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