Fungiseius, Moraza, María L. & Lindquist, Evert E., 2011

Moraza, María L. & Lindquist, Evert E., 2011, A new genus of fungus-inhabiting blattisociid mites (Acari: Mesostigmata: Phytoseioidea) from Middle America, with a key to genera and subgenera of the subfamily Blattisociinae, Zootaxa 2758, pp. 1-25 : 4-6

Fungiseius new genus

( Figs 1–60 )

Type species: Fungiseius armatus new species

Diagnosis. Adults of Fungiseius are distinguished apomorphically from those of other blattisociine genera by the following attributes: dorsal shield with lateral margins bearing a delineated strip extending from setae z2 to S5 and bearing some of r -marginal setae anteriorly and the series of S - lateral setae posteriorly; sternal or sternitigenital shield with gland pore at apex of endopodal extensions between legs I and II; female with small ventrianal or anal shield; female with deep postgenital furrow; male and female with deep postanal furrow and lacking opisthogastric setae JV3; hypostomatic setae hp2 minute; legs II greatly thickened, and with enlarged, curved, spine-like setae on dorsolateral surfaces of tarsus; genua III and IV with eight and nine setae respectively, lacking pv -1; tarsus I with one dorsobasal seta pd attenuate, erect; claws on legs I–IV with a basal swelling. Among the genera of Blattisociinae, adults of Fungiseius are strikingly similar to those of another fungus-inhabiting genus, Hoploseius , in having legs II greatly thickened and provided with spine-like setae. In contrast to Fungiseius , leg II of Hoploseius has enlarged spine-like setae on the ventral faces of the femur, genu, tibia and tarsus, and lacks enlarged curved setae on the dorsolateral face of the tarsus. Adults of Hoploseius differ in other apomorphic ways from those of the new genus in having the apical margin of the fixed cheliceral digit with a curved row of small, rasping teeth; females with an expansive ventrianal shield; genu I lacking setae pd -3 and av -2, and genua III-IV retaining seta pv -1, although lacking al -2.

Description. Idiosomal dorsum. ADULT FEMALE AND MALE ( Figs 9 , 38 ). Dorsal shield entire, without lateral incisions, well sclerotized and with delineated lateral rim extending from setae z2 to S5 and bearing a variable number of s or r setae, and all S1-S5; surrounding soft integument smoothly striate. Dorsal shield with a maximum complement of 37 pairs of setae ( Fig. 38 ), including 22 podonotal (j1-j6, z1- z6, s1-s6, r2-r5) and 15 opisthonotal pairs (J1-J5, Z1-Z5, S1-S5), or with complement reduced to 28 pairs ( Fig. 9 ), including 17 podonotal (j1-j6, z1, z2, z4, z5, s1-s6, r2) and 11 opisthonotal pairs (J5, Z1-Z5, S1-S5); dorsal setae moderately short, smooth, of similar lengths, or with two pairs of posterior setae (Z4-Z5) enlarged and modified. Dorsal shield with complement of 18 pairs of discernible pore-like structures (eight podonotal, ten opisthonotal), of which seven pairs (four podonotal, three opisthonotal) superficially appear secretory (gland pores) and 11 pairs (four podonotal, seven opisthonotal) non-secretory (poroids). Soft surrounding cuticle with five to eight pairs of r -R marginal setae and pair of marginal poroids idRp. Peritrematal plates narrowly uniting with dorsal shield anteriorly at level of setae z1 or free there ( Fig. 11 ); peritremes well developed, reaching to level between setae s1 and z1.

Idiosomal venter. ADULT FEMALE ( Figs 15 , 46 ). Tritosternum with laciniae free for most of length, their fused bases with a series of denticles or smooth ( Figs 5 , 42 ). Ventral shields variably ornamented, well sclerotized. Presternal region ornamented with pair of weakly sclerotized plates consolidated with sternal shield. Sternal shield entire, with strongly developed endopodal extensions between coxae I–II and II–III, that between legs I–II with a gland pore apically where abutting peritrematal/exopodal shield; sternal shield with three pairs of setae and two pairs of lyrifissures; setae st4 and poroids iv3 on metasternal plates that are free or narrowly connected to sternal shield ( Figs 15 , 46 ). Endopodal strips between coxae III and IV free, well defined. Epigynal shield with its rounded, hyaline anterior margin between legs III abutting or overlapping posterior edge of sternal shield, its posterior margin truncate; setae st5 on shield’s lateral margins, paragenital poroids iv5 on soft cuticle; deep postgenital furrow present with small postgenital platelets usually discernible. Opisthosomatic venter with well-developed metapodal platelets, nine pairs of setae (JV1, JV2, JV4, JV5, ZV1-ZV5), and three pairs of poroids, ivp conspicuous; setae JV3 absent. Opisthogaster with either small ventrianal shield bearing three pairs of ventral setae (JV1, JV2, ZV2) or oval anal shield, with paranal setae inserted at mid level of anus, and more elongate postanal seta; shield with a pair of gland pores gv3 on posterolateral margins, and a well-developed cribrum behind level of postanal seta; deep postanal furrow present. Peritrematal shield connecting with exopodal strips behind coxae IV, with two poroids and one gland pore in area behind stigma, and with poroid (ip1) and two weakly developed gland pores (gp1, gp2) along length of peritreme ( Fig. 9 ); exopodal strip continuous alongside peritrematal shield by coxae I– IV, with extensions between bases of coxae I–II, II–III and III–IV. Spermathecal apparatus of phytoseioid-type, but sometimes with minor duct difficult to discern emanating from embolus near base of sclerotized calyx ( Figs 18 , 47 ).

ADULT MALE ( Fig. 37 ). Form of tritosternum and presternal area as in female. Ventral shields ornamented with reticula, well sclerotized. Sternitigenital shield with five pairs of setae and three pairs of poroids, and with endopodal extensions between coxae I–II, II–III, and partially fused with those between coxae III–IV ( Fig. 37 ). Opisthosomatic venter with one or two pairs of metapodal platelets; soft integument with two or three pairs of setae and three pairs of poroids. Ventrianal shield large, narrowed at level of anal region, with four pairs of opisthogastric setae (JV1, JV2, ZV1, ZV2) and the three circumanal setae; attributes of circumanal setae, cribrum, and deep postanal furrow as in female; setae JV3, ZV3-ZV5 absent. Posteriorly, peritrematal shield and peritreme as in female.

Gnathosoma . FEMALE AND MALE. Gnathotectum with convex, denticulate anterior margin ( Figs 1 , 43 ). Chelicerae large ( Fig. 8 ), or small ( Fig. 41 ), without any conspicuous process along antiaxial or paraxial lateral surfaces basal to the digits; fixed digit with tiny pilus dentilis and row of small teeth along distal half of masticatory surface and one or two small rasping teeth (gabelzähne) subapically; movable cheliceral digit with three coarse teeth; arthrodial envelope margin smooth; movable digit of male unidentate; spermatodactyl digitiform ( Figs 35, 36 ). Deutosternum with seven transverse rows of denticles of similar width ( Fig. 45 ) or progressively wider basally ( Fig. 2 ), rows multidenticulate, all rows connected, or basal row free. Corniculi normal in form, well-separated from base to apex, shorter and stouter in male ( Fig. 32 ); internal malae highly variable in form ( Figs 2 , 45 ). Subcapitular setae smooth, hp1 and hp3 similar in length and longer than cp, lateral hp2 minute. Palpi with normal setation as described for Gamasina by Evans (1964); palpfemoral seta al and palpgenual setae al -1 and al -2 more or less spatulate; palptarsal apotele two-tined, with spatulate tips ( Figs 6, 7 ).

Legs. FEMALE AND MALE. Legs I to IV with pretarsi bearing paired small claws with basal swelling, paradactyli and rounded pulvillae ( Figs 30 , 57 ). Legs II enlarged, much stouter than other legs ( Figs 20 , 49 , 59, 60 ), and with strongly thickened, claw-like setae on dorsal and lateral surfaces of tarsus ( Figs 27 , 57 ). Legs II to IV with tarsus (excluding pretarsus) at most two times (1.3–1.5 for II, 1.7– 2.1 for III–IV) as long as tibia. Distal margins of coxae I–IV without prominent serrations or spur-like processes. Tarsus I with sensilla s inconspicuously lanceolate ( Fig. 26 ), and without markedly elongated setae apically; one solid, dorsobasal seta long, erect ( Fig. 25 ). Tarsi II– IV with apical setal processes ad -1, pd -1 long, as long as pretarsi (to the base of claws), and with acutely triangular apical process ventrally. Complement of setae on segments of legs I-II-III-IV normal for Blattisociinae as presented by Lindquist & Evans (1965): coxae, 2-2-2-1; trochanters, (4-6)-5-5-5; femora, 12 (2 2/1 3/2 2) - 11 (1 2/1 3/2 2) - 6 (1 2/1 1/0 1) - 6 (1 2/1 1/0 1); genua, (2 3/1 or 2 3/1 2) - (2 3/1 2/0 2) - (2 2/1 2/0 1) - (2 2/1 2 or 3/0 1); tibiae, (2 3/1 3/1 or 2 2) - (2 2/1 2/1 2) - (2 1/1 2/1 1) - (2 1/1 3/1 2); genua II and III each lacking pv -1 ( Figs 19-22 , 48-51 ). Leg setae collectively smooth. Legs of male without dimorphically modified setae.

Etymology. The name of the genus is a Latinized combination of the term fungus, meaning fungus, and seius or sejus, a Roman surname commonly used by authors to form names for genera of mesostigmatic mites. The name is masculine in gender, and indicates the habitat from which these mites have been collected.

Distribution and habitats. This genus is based on material associated with perennial fungal growths on decaying logs in two widely separated, subtropical to tropical New World localities, one from pine-oak forest south of the Isthmus of Tehuantepec in Mexico, and one from a locality in coastal lowland rainforest of Costa Rica.

Remarks. The genus Fungiseius is based on their adults having several apomorphies, some of which appear to be unique among the known taxa of Blattisociidae : (1) dorsal shield with delineated lateral rim extending from setae z2 to S5 and bearing z2 or s2, r2-r5, and S1-S5; (2) apex of endopodal extension of sternal or sternitigenital shield between legs I and II with a gland pore; (3) female with deep postgenital furrow; (4) male and female with deep postanal furrow; (5) opisthogastric setae JV3 absent; (6) hypostomatic setae h2 minute; (7) legs II much stouter than other legs; (8) strongly thickened claw-like setae on tarsi of legs II to IV, especially leg II; (9) genua of legs III–IV lacking seta pv -1. Attributes (1), (3), (4) and (8) appear to be unique to this genus. Although attribute (1) is superficially similar to a condition found in Orthadenella , the latter genus does not belong to this subfamily, in view of its females not having an apparently phytoseioid-type spermathecal system ( Athias-Henriot 1973; see discussion below). Also, the delineated rim of attribute (1) in Fungiseius is unique in carrying lateral setae S1-S5, leaving the R - marginals on soft cuticle, while the rim found in Orthadenella and among genera of the ascoid family Melicharidae differs in bearing most or all of the R - marginal setae, with the laterals inserted mediad the rim (personal observations). Attribute (7) is shared only with Hoploseius , whose members are also restricted to bracket fungi. Attributes (2) and (6) are uncertainly unique in that their presence or absence among other taxa of this and related families has not been confirmed, while (5) and (9) are homoplastic.

The apomorphic attribute of a “phytoseioid-type” sperm access system in adult females, on which the superfamily Phytoseioidea is based ( Athias-Henriot 1968, 1971; Alberti & Di Palma 2002; Lindquist et al. 2009), is difficult to observe in both species of Fungiseius , due to the reduced size and relatively weak sclerotization of the calyx, such that discernment of a minor duct emanating from the embolus is problematical. However, other, more readily observable attributes detailed by Lindquist & Moraza (2010) as diagnostic for the family Blattisociidae support placement of Fungiseius in this family.

Among the genera of Blattisociinae, adults of Fungiseius are strikingly similar to those of Hoploseius , whose members also dwell in bracket fungi, in having greatly thickened legs II. However, this appears to be an interesting case of convergence. Legs II of Hoploseius bear strongly thickened, spine-like setae on the ventral faces of the femur, genu, tibia and tarsus; these setae are apposed to one another, apparently for grasping structures, most probably those of the drosophilid flies used for phoresy ( Lindquist 1963). As adult males are similarly armed, but have not been found to be phoretic, the grasping function may also be used by both sexes in copulation. In contrast, legs II of both sexes in Fungiseius have slender setae on the ventral faces of the femur and genu; strongly spine-like setae are restricted to the tarsus, primarily on the dorsal and lateral faces. The latter setae are claw-like, not apposable, and probably are used for scraping or burrowing. Other than a within-genus tendency towards hypotrichy among some of the leg segments, which is subject to considerable homoplasy, members of these two genera do not share other apomorphic attributes that would indicate a sister-group relationship. Even the loss of seta pv -1 on genua III and IV in Fungiseius differs from the losses of setae al -2 and av -1 on genu III and of pd -3, al -2, and pl -1 on genu IV among some species in Hoploseius ( Lindquist & Evans 1965) . The affinity of Hoploseius with Lasioseius , based on the tricarinate form of at least some of the dorsal shield setae and the strongly formed ventrianal shield, is distinct from Fungiseius .

Among other genera of Blattisociinae, adult females of Fungiseius are similar to those of Aceodromus and Opilioseius in having a reduced ventrianal shield or an anal shield, and in the spermathecal apparatus having a weakly sclerotized calyx. These attributes are subject to considerable homoplasy among other genera of this subfamily, especially the species-rich Lasioseius (personal observations).

Figures

FIGURES 1 – 8. Fungiseius armatus n. sp., adult female: 1, gnathotectum; 2, subcapitulum; 3, corniculi, dorsal view; 4, labrum; 5, tritosternum, showing denticles at base of laciniae; 6, palpus, dorsolateral view; 7 a, detail of seta al of palpgenu; 7 b, detail of seta al of palpfemur; 8 a, chelicera, lateral view; 8 b, separate paraxial view of fixed digit.

FIGURES 9 – 14. Fungiseius armatus n. sp., adult female: 9, idiosoma, dorsal aspect with detail of peritrematal shield (arrows indicate delineated strip of dorsal shield margins bearing some of r - marginal and all S - lateral setae); 10, detail of separate views of dorsal setae denoted and lyrifissure; 11 a – b, detail of ventral view of dorsal and peritrematal shields; 12, detail of exopodal IV with peritremal poroidotaxy at level of coxa IV; 13, detail of denoted dorsal setae; 14, detail of dorsal ornamentation.

FIGURES 15 – 18. Fungiseius armatus n. sp., adult female: 15, idiosoma, ventral aspect; 16, detail of peritrematal shield, fused to exopodal strips between legs II – III and III – IV; 17, detail of sternal shielding; 18 a, b, detail of spermatheca.

FIGURES 19 – 24. Fungiseius armatus n. sp., adult female: 19 – 22, legs I – IV, excepting tarsi: 19, leg I excluding tarsus, laterodorsal view; 20, leg II, posterolateral view; 21, leg III, dorsal view; 22, leg IV, anterolateral view; 23, trochanter I, ventral view; 24, detail of denoted setae of tibia I.

FIGURES 25 – 31. Fungiseius armatus n. sp., adult female: 25, tarsus I, anterolateral view; 26, detail of apical seta on tarsus I; 27, tarsus II, posterolateral view; 28, tarsus III, dorsal view; 29, tarsus IV, dorsal view; 30, detail of ventral aspect of tarsus IV with ventral process; 31, detail of lateral aspect of tarsus IV. Abbreviation: t p, tarsal process.

FIGURES 32 – 37. Fungiseius armatus n. sp., adult male: 32, subcapitulum; 33, chelicerae, dorsolateral view; 34, chelicerae, detail of fixed digit with pilus dentilis; 35, chelicera, detail of movable digit and spermatodactyl; 36, detail of spermatodactyl; 37, idiosoma, ventral view.

FIGURES 38 – 41. Fungiseius clavulisetis n. sp., adult female: 38, idiosoma, dorsal aspect (arrows indicate delineated strip of dorsal shield margins bearing r - marginal and S - lateral setae); 39, detail of denoted dorsal setae; 40, chelicera, detail of movable digit; 41, chelicera, dorsal view.

FIGURES 42 – 47. Fungiseius clavulisetis n. sp., adult female: 42, tritosternum; 43, gnathotectum; 44, corniculi, dorsal view; 45, subcapitulum; 46, idiosoma, ventral aspect; 47, detail of spermatheca.

FIGURES 48 – 55. Fungiseius clavulisetis n. sp., adult female, legs I – IV, excluding tarsus: 48, leg I, posterolateral view; 49, leg II, posterolateral view; 50, leg III, dorsal view; 51, leg IV, posterolateral view; 52, coxa I, ventral view; 53, coxa II, ventral view; 54, coxa III, ventral view; 55, coxa IV, ventral view.

FIGURES 56 – 58. Fungiseius clavulisetis n. sp., adult female: 56, tarsus IV, dorsal view; 57, tarsus II, posterolateral view; 58, tarsus II, anterolateral view. Abbreviation: t p, tarsal process.

FIGURES 59 – 60. Photomicrographs of adult females in dorsoventral habitus view: 59, Fungiseius armatus n. sp.; 60, Fungiseius clavulisetis n. sp.