Mycterizon bellus (Distant, 1902), 2023

Salini, Santhamma, Gracy, R. G., Akoijam, Romila, Rabbani, Mehaboob K., David, K. Jacob & Roca-Cusachs, Marcos, 2023, Revision of Acesines Stal and Dunnius Distant, resurrection of Mycterizon Breddin (Hemiptera, Heteroptera, Pentatomidae, Pentatominae), and description of a new species from India, ZooKeys 1148, pp. 79-117 : 79

Mycterizon bellus (Distant, 1902) stat. rev.

Figs 63-68 , 69-75 , 76-79 , 80-85

Araducta bella Distant, 1900a: 427 (original description). Syntype: ♂, Punduloya, Ceylon, Atkinson Coll. 92-6, 116 (NHM), London, UK, lectotype (present designation); Syntype: ♀, Punduloya, Ceylon, Atkinson Coll. 92-6, 116 (NHM), London, UK, paralectotype (present designation).

Dunnius bellus Distant, 1902: 233, fig. 146 (redescription, figures of habitat in dorsal view, and mesothorax, metathorax and abdomen in ventral view; distribution); Bergroth (1908): 173 (catalogue); Kirkaldy (1909): 137 (catalogue); Distant (1918): 145 (synonymisation, additional distribution); Chatterjee (1934): 22 (host record, new records); Chandra (1953) (distribution); Mathur and Singh (1960): 20 (host); Salini and Viraktamath (2015): 12 (key to genera), 24 (checklist), 46, fig. 54 (illustration of dorsal habitus), 68, fig. 185 (illustration of external scent efferent system); Salini (2019): 126, fig. 8.20 (illustration of dorsal habitus).

Mycterizon bellus Breddin (1909): 279 (synonymisation); Kirkaldy (1909): 371 (catalogue).

Type locality.

Araducta bella . Ceylon (= Sri Lanka), Punduloya. Dunnius bellus . Ceylon (= Sri Lanka), Punduloya.

Type material.

Not examined, only type image was seen. The original description of A. bella is based on a male specimen whereas that of D. bellus was based on a female specimen. The syntype male specimen of Araducta bella Distant, 1900a: 427 (Ceylon: Punduloya, Atkinson Coll., 92-6, NHMUK 013588914) herein designated as lectotype (Figs 80-82 ) and the female syntype specimen of Araducta bella Distant, 1900a: 427 (Ceylon: Punduloya, Atkinson Coll., 92-6, NHMUK 013588915) is herein designated as paraletotype (Figs 83-85 ). Additionally, 31 specimens of this species are available in NHM (M Webb, pers. comm.). The image of the type is provided by courtesy of M Webb.

Material examined.

India: Andhra Pradesh: 1♀, Tirupathi , 22.x.2008, Yeshwanth, H. M. ex light trap (sodium vapour lamp) (NIM) ; 3♀, 3♂ ARS, Nellore , 14°25.790'N, 079°59.922'E, 03.iv.2009, Yeshwanth, ex light trap (sodium vapour lamp) (NIM) ; 2♂, ARS, Anakapalli , 17°41.855'N, 083°00.253'E, 5.iv.2009, Yeshwanth (NIM); Goa : 1♀, MRC. coll. Karnataka : 3♀, 1♂, Brahmavara, Udupi , 28.ix.2007, Naveen Kumar, ex light trap (sodium vapour lamp) (NIM) ; 2♀, Arabhavi, Belgaum , 12.ii.2008, Naveen Kumar, ex light trap (sodium vapour lamp) (NIM) ; 2♂, same data as former except 13.ii.2008, Yadava Babu ; 1♀, Bandipur, Hangla , 19.xi.2008, 11°42.075'N, 076°37.685'E, Yeshwanth (NIM) ; 1♀, Markanja, D. Kannada , 12.xi.2009, Umeshkumar, ex light trap (sodium vapour lamp) (NIM) ; 1♀, Hessaraghata , 1.xii.2008, Umeshkumar (NIM) ; 7♂, 2♀, Brahmavara, Udupi , 13°25'N, 74°45'E, 79 m, 29.v.2014, Naveen, ex light trap (NIM) ; 1♀, CPCRI, Vittal , 06.iv.2018, David, K. J. (NIM) ; Kerala: 2♀, Kozhikode, 24.i.2008, 11°16.678'N, 075°50.647'E, Naveen Kumar, ex light trap (sodium vapour lamp) (NIM) ; 1♂, 1♀, ZSI, Calicut, 11°25'N, 75°77'E, 18.xi.2012, Devaraj, R., ex light trap (sodium vapour lamp), NIM-2022 (NIM) ; 1♂, CPCRI, Kasaragod , 12°31'N, 74°57'E, 6.xii.2012, Umeshkumar, S., ex light trap (sodium vapour lamp), NIM-2022 (NIM) ; 1♂, same data as before except date 4.xii.2012 (NIM) ; 2♂, 1♀, ZSI, Calicut, 24.iv.2014, V. Naveen, ex light trap (NIM) ; 1♀, no label (NIM); Tamil Nadu : 1♀, Yelagiri, Javadi Hills , 16.vi.2016, Ramesh Kumar, A .

Redescription.

Colouration (Figs 63 , 64 ). Dorsum ochraceous with black irregular spots scattered over pronotum, scutellum and hemelytra; head ochraceous except narrow lateral margins of mandibular plates, two oblique, narrow longitudinal lines on disc of clypeus, black; antennae ochraceous; lateral margins of pronotum adjacent to humeri (including humeri), black; disc of scutellum with roughly anchor-shaped spot and one short oblique stripe each at basal angles of scutellum, black; connexivum with narrow, transverse, black stripe on anterior and posterior margin of connexivial segments, black; sometimes anterior 1/2 margin of each pleurite III-VII with longitudinal stripe, black; distal end of hemelytra with moderate size spot, ochraceous, sometimes with purplish shade; membrane smoky brown; ventral side ochraceous with the following markings: thoracic pleura laterally with irregular markings mainly formed by the coarse punctures, one roughly circular spot mesad at an oblique angle to each spiracles; short, narrow and transverse stripe below each spiracles on either side of abdominal sternites III-VII and anterior and posterior angles of each abdominal sternites III-VII, black; labium ochraceous with apex black; legs ochraceous except small nearly circular spots densely distributed on femora and tibiae (finer on tibiae) and apical 1/2 of claws, black.

Integument and vestiture. Body above covered with coarse, black punctures confluent to form irregular markings on dorsum especially on pronotum and scutellum. Ventral side of body with coarse and dense black punctures mostly concentrated towards lateral sides on thoracic sternites. Femora of legs with coarse, black, dense punctures and tibiae with fine black punctures. The punctures finer on abdominal sternites, concentrated towards laterally. Ventral side of genital capsule including posterolateral lobes with fine pale brown punctures; terminalia with valvifers VIII and laterotergite VIII with sparse, coarse, brown punctures.

Body glabrous, except the following: antennae with fine, golden pubescence; legs with setae moderately elongate and semi erect; tibiae with dense, brown, short, semi erect setae on ventral side and dorsally with moderately elongate brown setae, dense mat of setae at the posterior end of tibiae; tarsomeres on dorsal side with moderately elongate golden setae and dense mat of short, golden setae on ventral side of all tarsomeres; labium with sparse, golden setae. Genital capsule (middle margin of dorsal rim, posterolateral lobes and the caudal 1/2 of genital capsule on ventral side) with moderately elongate, dense, semi erect, golden setae. Female genitalia (valvifers VIII, valvifers IX, laterotergite VIII and IX) with moderately long, golden semi-erect setae.

Structure. See the generic redescription.

Male genitalia (Figs 66 , 68 - 76 ). Genital capsule (Figs 68 - 70 ) nearly quadrangular with posterolateral lobes (= caudal lobes) well developed and broadly rounded. Dorsal rim widely and deeply excavated concave with almost straight middle margin; infoldings of dorsal rim submedially with rounded lobe-like ingrowths (ls) towards posterior aperture. Ventral rim medially shallowly excavated and broadly concave. Paramere (Figs 71 , 72 ). Sclerotised, crown broad, subquadrate with one moderately elongate finger-like process at distal end and another short, stout, apically rounded process forming an acute angle with the distal finger-like process, short neck and small plate-like apodeme. Articulatory apparatus (Fig. 73 ). Support bridge complex excavated ventrally cup-like, for which the narrow, elongate, oval capitate processes (cp) attached with short dorsal connectives. Phallus. Phallotheca longer than broad, narrowed towards proximal end, dorsal region convex and ventral margin nearly straight (in lateral view); thecal process slightly developed on mid dorsal side at the distal end of phallotheca; a pair of minute, stout, sclerotised, ventrolateral tubercles at the posterior end of the phallotheca; four pairs of conjunctival processes; two pairs on dorsal side (inner pair, dcp I and outer pair dcp II), one pair each on ventral side (vcp) and lateral side (lcp) respectively. inner pair of dorsal conjunctival processes (dcp I) longest, broad and membranous, narrowed towards distal end; outer pair (dcp II) short, narrow, sclerotised with distal apex acuminate and membranous; ventral ones (vcp) moderately elongate, sclerotised and apically rounded; lateral pairs (lcp) shortest and membranous; processes of aedeagus (pa) fused mid longitudinally and sclerotised except median longitudinal part; partially enclosing aedeagus (ad) at the proximal end; aedeagus (ad) moderately elongate, sclerotised and tube-like with oblique phallotreme.

Female genitalia. (Figs 67 , 77-79 ). Valvifers VIII (vf VIII) transverse, broad and roughly quadrangular, with medial margins nearly straight; inner posterolateral angles rounded; posterior margin nearly straight; valvifers IX (vf IX) single, transverse, broad sclerite; laterotergites IX (lt IX) oblique, elongate with inner and outer margin straight, caudal margin orbicular or rounded, caudal apex smooth, without any denticle; laterotergite VIII (lt VIII) subtriangular, caudal margin smooth, slightly convex. A pair of ring sclerites (rs) oblong. Spermatheca. Spermathecal dilation long, regularly, obliquely fluted; proximal end of sclerotised rod, at the middle of lumen of spermathecal dilation, curved upwards and continued as distal spermathecal duct; proximal flange 1/2 the size of distal flange; apical receptacle (ar) orbicular with three elongate ductules, all facing towards distal rim and surpassing distal rim.

Measurements

(mm). Males (n = 5) as median (minimum-maximum). Body length 8.63 (8.08-9.09); head: length 1.90 (1.82-1.98), width (including eyes) 2.91 (2.85-3.01), interocular width 1.74 (1.65-1.78); lengths of antennomeres: I - 0.56 (0.46-0.68), II - 0.68 (0.54-0.77), III - 1.25 (1.20-1.33), IV - 1.58 (1.47-1.68), V - 1.55 (1.50-1.63); lengths of labiomeres: I - 0.63 (0.51-0.73), II - 0.86 (0.79-0.93), III - 0.60 (0.56-0.63), IV - 0.52 (0.46-0.60); pronotum: length 2.12 (1.92-2.33), width (including humeri) 5.07 (4.82-5.32); scutellum: length 4.17 (3.84-4.31), width (at basal angles) 3.33 (3.28-3.48).

Females (n = 5) as median (minimum-maximum). Body length 10.26 (9.83-10.73); head: length 2.05 (2.01-2.13), width (including eyes) 3.19 (3.12-3.37), interocular width 1.99 (1.97-2.04); lengths of antennomeres: I -0.59 (0.55-0.64), II - 0.68 (0.56-0.74), III - 1.35 (1.26-1.44), IV - 1.72 (1.71-1.76), V -1.74 (1.73-1.75); lengths of labiomeres: I -0.61 (0.54-0.66), II -0.97 (0.91-1.04), III - 0.61 (0.56-0.75), IV - 0.53 (0.51-0.60); pronotum: length 2.63 (2.40-2.78), width (including humeri) 5.95 (5.62-6.44); scutellum: length 4.94 (4.64-5.31), width (at basal angles) 3.90 (3.70-4.11).

Differential diagnosis and remarks.

Though the species Araducta bellus neither possess the basal abdominal tubercle nor the metasternal cruciform process, Distant (1900a) placed Araducta bellus in Araducta ; however, he mentioned in the redescription of Araducta : “… Metasternum with central, cruciform process, not notched posteriorly. Second abdominal segment with a central, broad, obtuse, spinous tubercle..." Later, Distant (1902) proposed the genus Dunnius and the original description of Dunnius again mentioned the characters of the central cruciform process and the basal abdominal tubercle, but he transferred Dunnius bellus from Araducta to Dunnius . Breddin (1909) recognised D. bellus as a distinct species (see comments under Mycterizon ) and found that it was not congeneric with Dunnius , hence proposed Mycterizon to accommodate it. However, Distant (1918) synonymised this genus with Dunnius and transferred Dunnius bellus back to Dunnius without justifying his action. The present study is in agreement with Breddin (1909) (see comments under Mycterizon ) and therefore Mycterizon bellus (Distant, 1902) is removed from synonymy with Dunnius bellus (Distant, 1902). The single male syntype of Araducta bella , presently lodged in NHM, London, UK, is herewith designated as lectotype and the female syntype as paralectotype, also currently in NHM, London, UK.

Distribution.

India: Bihar, Odisha, Tamil Nadu ( Distant 1918); Ceylon (= Sri Lanka) ( Distant 1900a).

Tribal placement of Mycterizon

The genus Dunnius originally included four species, viz., D. bellus , D. fulvescens , D. minor , and D. sordida (Kirby) (Rider, 2022). The aforementioned nomenclatural changes and new taxa descriptions ( A. sordida (Kirby, 1891), comb. nov; M. bellus (Distant, 1902), stat. rev.; D. laticeps (Zheng & Liu, 1987), comb. nov.; D. tridentatus (Xiong & Liu, 1995), comb. nov.; D. trifasciatus (Xiong & Liu, 1995), comb. nov.; and Dunnius barpetensis Salini & Rabbani, sp. nov.) led to the addition of two more species to the genus Dunnius . The genus Mycterizon , monotypic with M. bellus , is designated as type species by monotypy and presently considered as a member of Menidini , although its tribal placement is dubious. Breddin (1909) opined that Mycterizon is closely related to Antestia , a member of Antestiini . The tribe Menidini is a large and variable one, the monophyly of which has not yet been proved. It was formally named by Atkinson (1888) as Menidaria and was defined based on a wide variety of characters: basal abdominal segment is obtusely convex or with a slender spine or rounded or compressed; if tuberculate, tibiae rounded; very rarely obtusely tuberculate at middle; metasternum not elevated, mesosternal ridge with uniform breadth throughout its length; labium usually extending beyond mid coxae, either reaching or extending beyond basal abdominal segment; third labial segment sometimes slightly longer than second; tibiae usually sulcate, if rounded, basal abdominal sternum with a spine, which usually does not extend beyond mid coxae.

Based on the examination of Indian Menidini and perusal of literature revealed that the members of this tribe do not appear to share a common ancestor and can be broadly assembled into three groups based on the combination of characters like shape of the scutellum, presence/absence of abdominal spine/tubercle, development of metasternal carinae:

Group 1 - spatulate scutellum, elongate abdominal spine present, metasternal carina narrow throughout its length;

Group 2 - subtriangular scutellum, elongate abdominal spine present, metasternal carina narrow throughout its length;

Group 3 - subtriangular scutellum, abdominal tubercle present, apex of which is placed in metasternal carina (broadening posteriorly).

Mycterizon bellus does not fit into any of the above-mentioned groups, but rather possesses a unique combination of characters such as a spatulate scutellum, a narrow metasternal carina, and the absence of either an abdominal spine or a tubercle. It also possesses other characters such as the head flat above, as broad as 1.5 times the head length, the external scent efferent system with peritreme well developed, short, nearly reaching mid-metapleuron, spout-like, obliquely elevated to the pleural surface, the shape of the genital capsule including a dorsal rim (slightly concave medially) and ventral rim (broadly concave, without denticles on infoldings), the shape of parameres (broad crown-shaped with stout, straight, finger-like process), and the phallus with elongate conjunctival processes. Considering these remarkable differences, it cannot be considered as a member of Menidini . Therefore, it is removed from the tribe and its tribal status cannot be decided except through phylogenetic studies using both morphological and molecular characters of the taxa included in Menidini and other related tribes.

Figures

Figures 63 - 68. Mycterizon bellus (Distant), stat. rev. 63 habitus (dorsal) 64 habitus (ventral) 65 external scent efferent system (arrow showing the peritreme) 66 close up of posterior end of ventral side of male abdomen 67 close up of posterior end of ventral side of female abdomen (terminalia) 68 genital capsule (dorsal). Scale bars: 1 mm (63, 64); 0.5 mm (65); 0.1 mm (66 - 68).

Figures 69 - 75. Mycterizon bellus (Distant), stat. rev. 69 genital capsule (ventral) 70 genital capsule (caudal) 71, 72 paramere 73 articulatory apparatus 74 phallus (dorsal) 75 phallus (ventral). Scale bar: 0.1 mm. Abbreviations: ad - aedeagus; cp - capitate processes; ls - lobe-like ingrowths; pa - processes of aedeagus; dcp I - dorsal conjunctival processes (inner one); dcp II - dorsal conjunctival processes (outer one); lcp - lateral conjunctival processes; vcp - ventral conjunctival processes.

Figures 76 - 79. Mycterizon bellus (Distant), stat. rev. 76 phallus (lateral) 77 terminalia (dorsal) 78 terminalia (ventral) 79 spermatheca. Scale bar: 0.1 mm. Abbreviations: ad - aedeagus; ar - apical receptacle; rs - ring sclerites; lt VIII - laterotergite VIII; lt IX - laterotergite IX; vf VIII - valvifers VIII; vf IX - valvifers IX.

Figures 80 - 85. Mycterizon bellus (Distant), stat. rev. 80 label data of lectotype 81 lectotype (dorsal habitus) 82 lectotype (ventral habitus) 83 label data of paralectotype 84 paralectotype (dorsal habitus) 85 paralectotype (ventral habitus). Photographed by Mick Webb, NHM, London, UK.