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Cornigamasus pseudocliferius n. sp., new species of mite from China based on adults and deutonymphs (Parasitiformes: Parasitidae)

Yao, Mao-Yuan ¹ ; Chen, Jian-Xin ² ; Yi, Tian-Ci ³ and Jin, Dao-Chao ⁴

¹College of Agriculture, Anshun University, Anshun, 561000, P. R. China.
²College of Agriculture, Anshun University, Anshun, 561000, P. R. China.
³Institute of Entomology, Guizhou University, and Guizhou Provincial Key Laboratory for Plant Pest Management of Mountainous Region, Guiyang 550025, P. R. China.
⁴✉ Institute of Entomology, Guizhou University, and Guizhou Provincial Key Laboratory for Plant Pest Management of Mountainous Region, Guiyang 550025, P. R. China.

2024 - Volume: 64 Issue: 2 pages: 626-636

https://doi.org/10.24349/de1v-8oni
ZooBank LSID: 967B30E3-1B7F-4C8D-886F-84580404E703

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Original research

Keywords

description Cornigamasus new species China

Abstract

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Introduction

Mites of the family Parasitidae are common and geographically widespread predators of small invertebrates and their eggs. They live in forest soil, compost, manure, shore litter, and mammal and insect nests (Hyatt 1980). Parasitidae comprises 46 genera in two subfamilies, Parasitinae Oudemans, 1901 and Pergamasinae Juvara-Bals, 1972 (Hrúzová & Fenďa 2018; Makarova 2019; Juvara-Bals 2019; Yao et al. 2020a). The genus Cornigamasus, belonging to the subfamily Parasitinae Oudemans, was erected by Evans & Till (1979) with Gamasus coleoptratorum var. lunaris Berlese, 1882 as its type species. It is easily separated from other genera of Parasitinae by long corniculi extending beyond the anterior margin of the palp trochanter. Nine species of Cornigamasus have been described worldwide (Yao et al. 2020b), three species of which occur in China – Cornigamasus allotritosternus Yao, Guo, Yi & Jin 2020, C. lunaris Berlese, 1882 and C. oulaensis Ma, 1986 (Ma 1986; 2005; Gu et al. 1987; Ma & Bai 2017; Yao et al. 2020b). We here describe a new species of Cornigamasus based on deutonymph and adult specimens.

Material and methods

Species were extracted from the nest of Oryctolagus cuniculus (L.) and cow dung by Tullgren funnels for 12–24 hours, and collected into 75% alcohol. Mites were cleared in Nesbitt's solution and then mounted on slides in Hoyer's medium. Specimens were observed and illustrated under a Nikon DS–Ri2 microscope, and figures were edited with Adobe Photoshop CC2021. The measuring follows Yao et al. (2020b), and all measurements are given in micrometers (μm).

The system of idiosomal setal nomenclature follows Hyatt (1980). Terminology for the leg chaetotaxy follows Evans (1963a), palp chaetotaxy follows Evans (1963b) and adenotaxy and poroidotaxy follows Athias-Henriot (1971, 1975).

Results

Family Parasitidae Oudemans, 1901

Subfamily Parasitinae Oudemans, 1901

Genus Cornigamasus Evans & Till, 1979

Type species: Gamasus coleoptratorum var. lunaris Berlese, 1882

Diagnosis of genus. The diagnosis of Cornigamasus used here is based on that of Yao et al. 2020b.

Cornigamasus pseudocliferius Yao & Jin n. sp.

ZOOBANK: A412A76E-1180-4243-9A2B-56ECDC75564E

Material examined

Holotype — ♀ (slide no. AH-Cor.-F2018052401), encountered in the nest of Oryctolagus cuniculus (L.), Huangshan (170 m a.s.l., N 29°49′20″, E 118°16′1"), Anhui Province, China, May 24, 2018.

Paratypes — 4 ♀♀ (AH-Cor.-F2018052402–AH-Cor.-F2018052405) and six deutonymphs (AH-Cor.-DN2018052401–AH-Cor.-DN2018052406) same collection data as the holotype; 9 ♀♀ (GZ-Cor.-F2018031001–GZ-Cor.-F2018031009), 6 ♂♂ (GZ-Cor.-M2018031001–GZ-Cor.-M2018031006) and ten deutonymphs (GZ-Cor.-DN2018031001–GZ-Cor.-DN2018031010) encountered in cow dung, Huishui (343 m a.s.l., N 29°15′5″, E 118°5′6"), Guizhou Province, China, Mar. 10, 2018.

Material deposition — All specimens are deposited in the Institute of Entomology, Guizhou University, Guiyang, China (GUGC).

Diagnosis

Adult female and male — Both sexes moderately sclerotized; dorsal and ventral shields without reticulation; setae j3 distally pilose; tarsus I without ambulacrum. In the female, podonotal and opisthonotal shields bearing 20 and nine pairs of setae respectively; membranous cuticle of opisthosoma with eight pairs of setae distally pilose; opisthogastric shield bearing six pairs of setae, JV4 distally pilose. In the male, opisthonotal region with three pairs of setae distally pilose (Z1, Z3 and a pair of setae located on posterior edge); opisthogastric region with 13 pairs of setae, of which two pairs (JV4 and JV5) distally pilose; femur Ⅱ with a main spur and axillary process, genu II with a spur.

Deutonymph — Idiosoma weakly sclerotized. Dorsal shields without reticulation. podonotal and opisthonotal shields bearing 18 and nine pairs of setae, respectively; s6 off shield; opisthogastric region bearing 15 pairs of setae. All dorsal and ventral setae smooth.

Description

Female — (n=14) (Figures 1–2)

Dorsal idiosoma (Figure 1A). Idiosoma moderately sclerotized, length 846–991, width 560–589, oval in outline and yellowish or brown in color. Dorsal shields without reticulation; Posterior margin of podonotal shield convex, fitted closely with concave anterior margin of opisthonotal shield. Podonotal shield, length 418–446, width 444–475, bearing 20 pairs of setae, which of j1, j3, j4, z5 and r3 thickened and distally pilose. Setae r2 (16–18), r4 (16–18) and r6 (14–16) off shield. Podonotal shield distinctly broader than opisthonotal one, length 215–241, width 232–258. Opisthonotal shield bearing nine pairs of setae, of which Z1 and Z3 thickened and distally pilose. Membranous cuticle of opisthosoma with 11–12 pairs of setae, of which eight pairs thickened and distally pilose. Lengths of dorsal setae on the shields: j1 36–39, j2 14–16, j3 39–42, j4 39–43, j5 14–16, j6 140–15, z1 18–20, z2 12–14, z3 12–14, z4 12–15, z5 40–44, z6 13–15, s1 15–17, s2 12–14, s3 13–14, s4 12–14, s6 13–15, r3 68–72, r5 14–16, J1 15–18, J2 16–17, J3 15–17, Z1 51–54, Z2 15–17, Z3 58–66, Z4 14–16, S1 14–15, S2 16–18.

Ventral idiosoma (Figure 1B). Tritosternum with pilose laciniae, length 88–108, base length 49–56, flanked by two pairs of presternal platelets close to each other, of which postero-medial pair clearly larger than anterior pair. Sternal shield with two pairs of poroids (iv1–iv2) and three pairs of setae (st1–st3), setae st2 slightly thicker and shorter than st1 and st3. Posterior margin of sternal shield deeply notched. Metasternal shield clearly detached from sternal shield and genital shield. Epigynium with anterior half narrow and pointed, posteriorly separated from opisthogastric shield, glands gv2 with three openings. Endogynium (Figure 1C), length 107–129, width 75–92, comprised of oval-like structures and with a protruding posterior lamella. Opisthogastric shield bearing six pairs of setae and three circum-anal setae. Seta JV4 distally pilose, others smooth. Opisthogastric soft cuticle with seven pairs of setae, of which four pairs distally pilose. Peritreme, length 387–418, extending anteriorly to the level of coxa I. Lengths of ventral setae on the shields: st1 49–52, st2 35–37, st3 47–50, st4 25–27, st5 29–31, JV1 30–33, JV2 34–37, JV3 39–41, JV4 50–52, ZV1 22–24, ZV2 32–34, po 18–20, pa 14–16.

Gnathosoma. Gnathotectum (Figure 1D) with one prong, distal end of prong round or truncate, emerging from denticulate base. Palp length 226–254, trochanter bearing setae v1 and v2, v2 pilose distally and set on tubercle; femur with five setae (al, d1, d2, d3 and pl), of which al spiculate distally; genu with six pairs of setae (al1, al2, d1, d2, d3 and pl), of which al1 and al2 spatulate distally. Trochanter, femur and genu of palp as in Figure 1E. Corniculus (106–138), long, slender and reaching midpoint of palp femur; deutosternal groove with 10–11 denticulate rows; seta h1 (68–72), h2 (38–42), h3 (96–112) and pcx (46–53) smooth (Figure 1F). Fixed digit of chelicera with four teeth, movable digit bearing four teeth (Figure 1G).

Legs (Figure 2). Lengths of legs Ⅰ–Ⅳ: 685–756, 556–580, 470–514, 672–723 respectively. Tarsus I without ambulacrum, with seven clavate sensory setae, shorter than tactile setae. Coxa I and trochanter I with apophysis at anterolateral side. Setae av1, al1, pv1 and pl1 on tarsi Ⅱ–Ⅳ modified to short and thick spurs. Most leg setae acuminate and smooth.

Male — (n=6) (Figure 3)

Dorsal idiosoma (Figure 3A). Idiosoma length 646–788, width 424–571, shape and colour as in female. Holodorsal shield covering entire dorsum, with a suture closely anterior to setae Z1. Setae j1 (33–35), j3 (32–34), j4 (32–34), z5 (36–39), r3 (46–50), Z1 (38–40), Z3 (40–41) and a pair of setae (62–65) located on posterior edge thickened and pilose distally as in female, all other setae short and smooth.

Ventral idiosoma (Figure 3B). Tritosternum absent. Genital opening flanked by two pairs of presternal platelets, posterior one quadrilateral and evidently larger than anterolateral one, which is sometimes fragmented into two platelets. Sternogenital shield bearing five pairs of smooth setae (st1–st5), of which st4 (22–24) shorter than others, st1–st3 and st5 subequal in length (27–31), and three pairs of poroids. Posterior margin of sternogenital shield separated from opisthogastric region by a transverse suture. Opisthogastric region with 13 pairs of setae, of which JV4 (39–43) and JV5 (42–43) stout and pilose distally. Setae pa (17–18) longer than po (12–15). Peritreme length 317–436.

Gnathosoma. Palp length 188–265, trochanter, femur and genu as in Figure 3C. Fixed digit of chelicera with three teeth, movable digit with a denticulated tooth (Figure 3D). Central prong of gnathotectum (Figure 3E). Lengths of setae: h1 65–69, h2 17–20, h3 68–72, pcx 29–32 (Figure 3F). Other characteristics as in female.

Legs. Lengths of legs I–Ⅳ: 610–706, 479–521, 437–494, 597–698 respectively. Leg Ⅱ obviously stouter than others. Femur Ⅱ with a main spur (proximal) and an axillary process (distally), genu Ⅱ and tibia Ⅱ with a spur (Figure 3G). Other characteristics as in female.

Deutonymph (n=16) (Figures 4, 5)

Dorsal idiosoma (Figure 4A). Idiosoma weakly sclerotized, usually yellowish or tawny in color, length 569–628, width 404–436. Podonotal and opisthonotal shields distinct and without reticulation. Posterior margin of podonotal shield (length 339–363 and width 328–367) convex, fitted closely into concave anterior margin of opisthonotal shield (length 130–152 and width 256–286). Podonotal shield with 18 pairs of setae. Setae s2, s6, r2, r4, r6 off shield and equal in length (27–31). Opisthonotal shield bearing nine pairs of setae. Membranous cuticle of opisthosoma with nine pairs of setae. All dorsal setae smooth. Lengths of dorsal setae on the shields: j1 33–36, j2 25–27, j3 30–34, j4 30–33, j5 27–29, j6 27–29, z1 24–26, z2 25–27, z3 29–31, z4 30–33, z5 35–37, z6 25–27, s1 26–29, s3 26–29, s4 27–30, r3 33–35, r5 29–31, J1 24–26, J2 25–27, J3 24–26, J4 24–26, Z1 29–32, Z2 25–27; Z3 32–35, S1 26–28, S2 28–29.

Ventral idiosoma. Tritosternum (Figure 4B) with two pilose laciniae (114–128) and a smooth base (45–56), flanked by two pairs of presternal platelets close to each other, comprising a large irregular inner pair and a smaller crescent-shaped outer pair (Figure 4C). Sternal shield bearing four pairs of setae (st1–st4), of which setae st1 longest, st4 shortest. Opisthogastric region with 15 pairs of setae and two pairs of sclerites, located between setae st5, JV1 and ZV1. Metapodal shield located lateral setae ZV1 and ZV2. Anal shield reticulated. pa (22–25) longer than po (16–18). All ventral setae smooth. Peritreme length 317–338. Lengths of setae: st1 31–34, st2 29–32, st3 29–33, st4 24–27, st5 20–24, JV1 28–30, JV2 31–33, JV3 30–33, JV4 37–38, JV5 36–39, ZV1 19–22, ZV2 30–32, ZV3 29–31, ZV4 27–29, SV2 20–24, SV3 28–30, SV4 32–34.

Gnathosoma. Palp length 182–205, other characters as in female; trochanter, femur and genu as in the Figure 4D. Gnathotectum similar to adults in shape, except that some denticles near medial prong smaller than in adults, without forked end (Figure 4E). Lengths of setae: h1 50–56, h2 28–32, h3 65–69, pcx 42–46 (Figure 4F). Fixed digit of chelicera with three teeth, movable digit with five teeth (Figure 4G).

Legs (Figure 5). Lengths of legs I–Ⅳ: 613–637, 467–495, 407–443, 578–624, respectively. Tarsus I with an ambulacrum. All leg setae simple and smooth. Other characteristics as in female.

Other stages — Unknown.

Etymology

This species is named after its similarities to C. ocliferius Skorupski & Witaliński, 1997.

Differential taxonomy

The newly described species is morphologically similar to adults of C. ocliferius in the setal locations, shape and number on the podonotal shield and the absence of ambulacrum on tarsus I (Skorupski & Witaliński 1997; Witaliński 2014; Negm 2016; Hruzova & Fend'a 2017). The male of C. ocliferius was reported as a holotype. C. pseudocliferius n. sp. male is distinguished from C. ocliferius by the shape of setae, of which j4, JV3, ZV2, ZV3 and SV1 are smooth rather than finely pilose; C. pseudocliferius n. sp. male is also distinguished from C. ocliferius by the armature of legs, of which the genu I and genu Ⅳ are smooth rather than bearing a spur; as well as by the number of spurs on leg Ⅱ. In C. pseudocliferius n. sp., the femur Ⅱ bears calcar and axillary spur and genu Ⅱ is equipped with a spur, whereas in C. ocliferius there is only a small conical spur on femur Ⅱ and the spur on genu Ⅱ is absent.

In the famale, C. pseudocliferius n. sp. is distinguished from C. ocliferius by the form of the setae on the membranous cuticle of opisthosoma, of which eight pairs are thick and distally pilose rather than ten pairs; C. psuedocliferius n. sp. is also distinguished from C. ocliferius by the number of presternal platelets, it has two pairs rather than one pair; as well as by the arrangement of poroid idZ3, which is located anterolaterally to seta Z3 rather than posterolaterally.

In the deutonymph, C. pseudocliferius n. sp. is distinguished from C. ocliferius by the dental number on the fixed digit of chelicera, which has three teeth rather than five teeth; C. psuedocliferius n. sp. is also distinguished from C. ocliferius by the number of setae on the membranous cuticle of opisthosoma, which bears nine pairs rather than twelve pairs.

Key to species of the genus Cornigamasus known in China

Females

1. Ambulacrum on tarsus I absent; opisthonotal shield with two pairs of distally pilose seta
...... C. pseudocliferius n. sp.

— Ambulacrum on tarsus I present; opisthonotal shield with three or 12 pairs of distally pilose setae
...... 2

2. Podonotal shield with four and opisthonotal shields with three pairs of distally pilose setae
...... 3

— All dorsal setae distally pilose setae
...... C. oulaensis

3. Endogynium with lateral lines forming a curtain-shaped decoration bilaterally and a conchoidal base
...... C. allotritosternus

— Endogynium with a transversely oriented granular band at posterior margin with a forward-protruding tooth on one side
...... C. lunaris

Males

1. Ambulacrum on tarsus I absent; podonotal shield with five pairs of distally pilose setae
...... C. pseudocliferius n. sp.

— Ambulacrum on tarsus I present; podonotal shield with four or 23 pairs of setae pilose distally
...... 2

2. Podonotal and opisthonotal shield with four pairs of distally pilose setae
...... 3

— All dorsal setae distally pilose
...... C. oulaensis

3. Tritosternum present; spurs on genu Ⅱ and tibia Ⅱ located close to a middle position
...... C. allotritosternus

Tritosternum absent; spurs on genu Ⅱ and tibia Ⅱ located at the distal margin
...... C. lunaris

Deutonymphs

1. Opisthonotal shield with nine pairs of setae
...... C. pseudocliferius n. sp.

— Opisthonotal shield with 12 pairs of setae
...... 2

2. Some setae (j1, j4, r3, z5, Z3, J5, Z6) thick and distally pilose
...... C. allotritosternus

— All dorsal setae distally smooth and pointed
...... 3

3. Podonotum with 18 pairs of setae
...... C. lunaris

— Podonotum with 19 or 20 pairs of setae
...... C. oulaensis

Acknowledgement

We express our thanks to two reviewers for their insightful comments on the manuscript. We sincerely thank Dr. Bruce Halliday offered the help to revision for English writing. This work was supported by the National Natural Science Foundation of China (No. 31872275 and 32160118), PhD Foundation of Anshun University (asxybsjj202211 and asxybsjj202212), Key Laboratory of Plants Protection Informatization for Featured and Efficient Agriculture in Central Guizhou Province (Qianjiaoji KY [2022] No. 052).

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