A new genus and species of oriental Colobathristidae (Hemiptera: Heteroptera) with a key to eastern hemisphere genera and morphological and functional considerations.
Abstract--A female of Schuhacantha bifurcata gen. n. et sp. n. (Hemiptera: Heteroptera: Colobathristidae: Colobathristinae) is described from continental Malaysia (Pahang). The autapomorphies of the genus are a robust bifurcate process situated at the middle lobe of the pronotum and ah extremely short labium; a potential synapomorphy with Centromus Bergroth, 1910 is a strongly protruding, bill-shaped ovipositor. The first key to Eastern Hemisphere genera of the Colobathristidae which are distinct from the Neotropical fauna is provided. Morphology as well as diagnostic and functional significance of some structures (antennal sclerite, pronotal process, evaporatorial system, abdominal laterotergites, forewing venation, femoral spine, female terminalia) are discussed.Key words: Heteroptera, Colobathristidae, new genus and species, Malaysia, key Oriental genera, morphology, function.
INTRODUCTION
The family Colobathristidae is grossly understudied despite its fascinating unique morphology, biology and distribution and the abundance of undescribed taxa. The morphology and development remain unelucidated; in several Neotropical genera males are dimorphic with one morph being gynaecoidal with female-like somatic anatomy; and colobathristid distribution is tropical with the conspicuous absence in Africa and Madagascar. The present range of the family is disjunct, with taxa from the Oriental and Neotropical faunas distinct at the genus level.
The Oriental distribution extends from southern India and Sri Lanka (Kerzhner's, 2001 statement that no species are known from the Indian subcontinent is erroneous) to the northern and southern territories of China (Horvath, 1916; Hsiao, 1977) and Taiwan, and covers the entire Indo-Malayan continent, Great Sundas, at least part of Wallacea (including Philippine Is), Fiji, and New Guinea, with Phaenacantha (Phaenacantha) australiae Kirkaldy, 1908, reaching northern Queensland (Stys, 1966b). The New World distribution is limited to tropical parts of Neotropical region (Panama and northern parts of South America) and includes the high Cordilleras of Peru and Bolivia.
The classical period of study of the taxonomy of Colobathristidae (1835-1922) is marked by the early publications by Burmeister and Stal continued later by Breddin, Bergroth, Distant, Karsch, Kirkaldy and mainly Horvath who provided the only available monograph of the group (Horvath, 1904). In the post-war period only Kormilev and Stys published regularly on the family, and Carvalho, Coscaron, Costa, Dellape, Ghauri, Henry and Hsiao occasionally.
In the present paper, we describe a new curious genus and species from peninsular Malaysia. Description of the species is more detailed than usual as this single species from this poorly known family reveals many generally important and overlooked diagnostic characters and the general and functional morphology. We discuss the fragmentation of antennal sclerites, the possible function of the pronotal process and profemoral spine, the possible link between mesoscutellar spine presence and forewing shape, forewing venation, and the possible involvement of forewings and basiabdominal laterotergites in the spread of repellent secretion, and some aspects of potential antipredatory mechanisms. We include the first key to the Oriental genera.
DEDICATION
We dedicate the paper to our long-standing friend Randall Tobias Schuh on the occasion of his 70th birthday. We greatly appreciate his contribution to general hemipterology, theoretical systematics and phylogenetics as well as his organizational activities benefiting the entire community of bug-lovers and bug-students. The senior author will never forget his stay in Toby's home during his fellowship at the American Museum of Natural History and his dedication and friendliness during our joint work. Actually, the paper is dedicated both to Toby and to Randallius Tobiasius Schuhius.
MATERIAL AND METHODS
Only the holotype female of this new taxon is known; hence some characters could not be examined properly (e.g., thoracic sterna, female terminalia). We also did not attempt to clean some areas covered with glue, in particular the ventral laterotergites II and III that may function as evaporatoria. The antennal and tarsal units are conveniently called "segments." Authors of the Oriental genera of the Colobathristidae are quoted in full in the Key.
All illustrations are of Schuhacantha bifurcata Stys and Exnerova, gen. et. sp. n., female holotype. All photographs were made by a stacking method and are copyrighted to the Naturhistorisches Museum Wien, Austria. All the line drawings are free-hand schemes unless the size is recorded. All measurements are in millimeters.
SCHUHACANTHA, NEW GENUS
TYPE SPECIES: Schuhacantha bifurcata sp. n. by present designation.
ETYMOLOGY: Schuh- (surname of R.T. Schuh) and--acantha (latinized spelling of Greek akantha = thorn, spiny)--according to presence of a spiny pronotal process; gender feminine.
DIAGNOSIS: Female: Antennae and legs long and thin, cephalic stridulatory apparatus absent, mesoscutellum with an upright spine, corium with a triangular cell. Eyes shortly stylate; ocelli distant from each other, the interocellar distance distinctly shorter than distance from ocellus to eye; labium not reaching anterior coxae. Midlobe of pronotum with a strong and high perpendicular process bifurcating in a transverse plane; hindlobe of pronotum simple. Metapleuron with a rounded posterodorsal metepimeral process. Legs unarmed except for a curved spine situated subapically on fore femur; first tarsal segment much longer than the second and third together. All of mesopleuron, metapleuron and abdominal ventral laterotergite II with mycoid evaporatorial microsculpture; metapleural auricle vertical, narrow and pointed. All abdominal ventrites distinct, III and IV subconnate but intersegmental line present, ventrite V at least twice as long as any other ventrite. Abdominal segment VII simple, produced neither dorsally or ventrally; terminalia strongly protruding, bill-shaped, formed by a composite dorsal plate and a pair of lateroventral plates. Abdominal spiracles 2-4 on dorsal laterotergites, 5-7 on ventral laterotergites; set of abdominal trichobothria complete. Head and prothorax continuously covered by appressed tomentum; prothorax with a deep, dense and regular punctation.
DIFFERENTIAL DIAGNOSIS (see also the Key): Schuhacantha differs from all other genera of Colobathristidae by the extremely short labium (Fig. 1B) and the presence of a bifurcating vertical process on the midlobe of the pronotum (Figs. 1C, D, 2E). The pronotal midlobe of all the other Oriental (as well as Neotropical) genera is unarmed; if any pronotal spines are developed, they occur on the hindlobe--a pair of humeral spines in Centromus or an unpaired discal spine in Discocentrus. Centrornus also shares with Schuhacantha (Fig. 3D, E, F) a strongly protruding ovipositor (a potential convergence shared with the Neotropical Peruda Distant, 1888) whereas Discocentrus (jointly with Phaenacantha) differs from the all the other Colobathristidae by absence of the apicicorial triangular cell. Possibly also a deep and anteriorly bifid interocellar pit of Schuhacantha (Fig. 2B) is unique. Extremely long and thin antennae and legs, and left and right abdominal laterotergites VII mutually free substantiate inclusion of Shuhacantha within the Colobathristinae.
SPECIES INCLUDED. Only the type species, Schuhacantha bifurcata sp. n., based on a female from peninsular Malaysia.
Schuhacantha bifurcata, new species Figures 1-4
HOLOTYPE FEMALE: MALAYSIA: Benom Mts.: 15 km E Kampong Dong: 700 m, 3.53 N 102.01 E, 1.iv. 1998, Dembicky et Pacholatko leg. Card-mounted; right antennal segment IV and right hind leg missing; right part of the pronotal bifurcate process broken and missing; part of thoracic and base of abdominal cuticle covered by glue. Deposited in the Department of Entomology, Naturhistorisches Museum, Wien.
TYPE LOCALITY: Peninsular Malaysia, Pahang Province, Benom Range.
GENERAL FACIES (Fig. 1A): Slender, macropterous, with very long and thin extremities, inconspicuous coloration, head and thorax with silky appressed tomentum. Body length 11.2, ratio body length: max. body width = 5.54.
COLORATION (Fig. 1A,B): Head and pronotum: Black, with somewhat variegate appearance owing to small piceous (e.g., humeral tubercles) to light brown (e.g., clypeus) areas, middle and hind lobes of pronotum concolorous. Mesoscutellum: Black, lateral margins and proximal part of scutellar spine yellowish. Lateral and ventral parts of thorax (incl. supracoxal lobes) black to piceous. Antenna: Segment I pale brown with blackish streaks, segments II-IV dark piceous, IV with a basal non-contrasting pale-brown ring. Labium and legs yellowish brown, profemoral spine black, distal halves of tarsi blackish; some faces of femora and tibiae appearing infuscate (depending on the angle of observation). Hemelytra: Transparent, live veins and a short basal stretch of RP on the membrane yellowish brown; distal sector of costal margin posterior to triangular cell (=apicicorial plate) with a contrastingly dark brown submarginal streak. Abdominal dorsum: Dorsites I and II (incl. dorsal laterotergites) and proximal part of mediotergite III piceous, dorsal laterotergites III-VII yellowish with orange hue, linear inner laterotergites III-VI contrastingly dark brown, distal part of mediotergite III and mediotergites IV-VII orange with an indistinctly delimited infuscate medial streak on IV-VII. Venter: Ventrite II and sternum III piceous to gradually brown, ventral laterotergites III-VII pale yellowish, sterna and terminalia orange, lateral parts of sternum IV and trichobothria-bearing areas V-VII infuscate. VESTITURE AND SCULPTURE: Head mostly covered by silvery-golden appressed tomentum (Fig. 1A, B) obscuring rough and irregular sculpture. The same true for the prothorax, tomentum covering the large, deep, dense, and regularly distributed punctures as well as the stem of the pronotal process (Figs. 1C,D, 2E), only the long branches of the process, humeral tubercles, and transversally wrinkled supracoxalia without tomentum. All punctures with short and erect stiff setae making for a stubby appearance of prothorax. Black proximal part of mesoscutellum densely punctured, the spine and posterior margin smooth, punctures and basis of spine with similar vestiture as on prothorax. Lateral wall of pterothorax with moderately long and moderately curved stiff setae arising from deep pits. For mesopleuron, metapleuron and ventral abdominal laterotergites II and III see under "Pterothorax--lateral parts." Ventral pilosity of first tarsal segment strikingly dense. Forewings glabrous, smooth, and shiny. Dorsal abdominal laterotergites smooth to shagreened, mediotergites VI and VII with dense, fully appressed pubescence. Ventral abdominal laterotergites IV-VII smooth to shagreened, bare to covered by fully appressed macrotrichia. Abdominal sterna II, III and lateral parts of IV heavily punctured, the others without punctation, covered with short, appressed macrotrichia, some parts pruinose. Terminalia smooth, segment IX, ventral laterotergites VIII, ventrolateral plates (particularly on ventral face) and valvular projections with long and strong macrotrichia. STRUCTURE: Head: Very short, dorsum sub-horizontal, eyes shortly stylate, anterior part nearly vertical. Dorsum (Fig. 1A): Antennal insertion situated only slightly anterad to eyes. Anteclypeus only slightly protruding in dorsal view. Eyes: large, multifacetted, eye stalks formed by enlarged ocular sclerite, in lateral view much exceeding the dorsum of head. Dorsal ocular index 0.40. Ocelli small, nearly flat, widely separated, interocellar distance 0.8 times as long as distance from ocellus to eye. Areas without vestiture: (a) depressed paired subcircular spots lateral to ocelli, (b) very deep, unpaired interocellar pit (Fig. 2B) gradually raising anterad, provided with a linear median, and extending anterad as a pair of spikelike depressions, (c) a pair of C-shaped spots between and posterior to the insertions of antennae. Antennal selerite (Fig. 2C, D): No outstanding antennal tubercle present. A low, semi-ring-shaped mesal and dorsal (posterior) wall of the antennal sclerite entire, whereas the higher ventral (anterior) and lateral wall fragmented into seven sclerites, four of them crescent-shaped and distinctly delimited, the fifth forming basis of antennifer, an indistinctly delimited sixth represented by a sclerotization within the basi-antennal membrane (a diffused prescapite?). Antennifer individualized, rectangular, plate-shaped, prominent, perpendicular to the cranial wall, articulating with the stalk of the pedicel; distal part turning mesad. Anterior, anterolateral and ventral faces (Figs. 1B, 2A): Clypeus: vertical, sharply delimited, formed by flat and broad postclypeus, delimited by a constriction from a laterally compressed and apically truncate anteclypeus. Distal half of anteclypeus flanked by narrow and smooth, apically widening lateroclypeal areas. Anteclypeus much longer than pointed mandibular plates, the latter reaching half the length of anteclypeus and flanked by extremely narrow, only subapically arcuately extended maxillary plates reaching the dorsal side of bucculae. Apex of anteclypeus thus surrounded in front by labrum, and from sides by lateroclypeal extensions attached ventrally to maxillary plates. Bucculae short and low, embracing basis of first labial segment and fusing together immediately behind the latter. Gula simple, bisinuate in profile. Labrum (Fig. 2A): Triangular, basis of epipharyngeal process sclerotized, rounded, triangular, its distal part simple, with sparse transverse corrugation, reaching nearly the apex of 2nd labial segment. Labium (Fig. 1B): Four-segmented, extremely short, scarcely exceeding, prosternal collum, labial formula (the longest segment first) I = IV--II--III. Segment I stout, much higher than the other segments, III basally constricted, IV apically diagonally (dorsally) and vertically (ventrally) truncate, intersegmental boundaries I-II diagonal, II-III and III-IV vertical. Antennae (Fig. 1A): Long and thin, 0.95 times as long as the body, antennal formula (the longest segment first) IV-III-II-I. Segment I 1.23 times as long as the transocular width, thicker than others, gradually thickening distad, basis stalked; II-IV flagelliform, II slightly incrassate distad, IV apically pointed, subarcuate. Prescapite absent; prepedicellite, preflagellite and interflagellite present, inconspicuous. PROTHORAX, DORSAL PART (Fig. 1A; sternum not examined): Collum: Dorsally narrow, linear, with a regular row of large punctures. Midlobe of pronotum (ratio max W: L 0.38): Strongly convex and somewhat gibbous (higher than head), posterior margin deeply impressed, submedially concave, medially convex and produced, the medial extension bearing a strong and high, twice forked pronotal process (Figs. 1C,D, 2E).The process formed by unpaired thick vertical stalk, the short and thick anterior branches directed anterad and acutely pointed, long posterior branches directed diagonally laterad, much longer and more slender, diverging and glabrous; span of the tips of long branches taking 60% width of midlobe. Posterior lobe of pronotum (ratio max W : L 0.68): More gibbous than midlobe, subproximally with well marked humeral tubercles and medial boulder-shaped protuberance; the very posterior sector depressed, flat, with hardly marked posthumeral lobuli, posterior margin straight. PROTHORAX, EATERAL PARTS: Collum: Widening lateroventrally and forming a complete multipunctate ring. Midlobe: Continuing laterad, delimited from short propleuron by horizontal notopleural sulcus anterior to supracoxal lobes; a depression delimiting the "proepimeral lobe" (=ventral continuation of posterior lobe of pronotum) short, pointed, contacting posterior prosupracoxale and bearing a groove starting in front of humeral angles and terminating at the posterior margin of "proepimeral lobe." MESOSCUTTELLUM (Fig. 1A): Broadly semicircular (ratio L : max W 0.49); lateral marginal fringes flat, impunctate; disc elevated, punctate, apically produced in a smooth, diagonal or subvertical spine (details unknown). PTEROTHORAX, LATERAL PARTS: Both the mesopleuron and metapleuron as well as the ventral abdominal laterotergltes II and III seem to be involved in the distribution and maintenance of repellent secretion; for this reason they are described together as a potential functional unit. Mesopleuron: Entire, densely but roughly and irregularly punctured excepting (a) a transverse area in front of anterior supracoxal lobe, (b) anterior supracoxal lobe, and (c) posterior supracoxal lobe provided with two deep longitudinal grooves. The whole of mesopleuron [inclusive (a) and (c)] with mycoid evaporatorial sculpture, only (b) smooth and brilliant. Metathoraeie spiracle: Unusually high, filling the entire length of meso-metapleural sulcus. Lateral metathoraeic wall (Fig. 3A): Formed by (a) triangular anterodorsal sclerite (ventrally turned part of metascutum?), (b) long, broad and compact metepisternum forming unusually large precoxale, (c) auricle of the metathoracic gland opening (Fig. 3C) nearly attached to (d) anterior supracoxale, and (e) posterodorsal rounded metepimeral process (Fig. 3A, B) continuous with a small wedgelike area behind anterior supracoxale and with major part of metepisternum (b). The whole of lateral wall (a-e) with distinct mycoid evaporatorial sculpture (possibly excepting the smooth ventral part of the auricle). Punctation shallow, sparse and regular on (a), deep, dense and irregular on most of (b); punctation lacking the part of (b) dorsal and posterior to supracoxale, and on (c), (d) and (e). Macrosculpture of metepisternum becoming villiform ventrad. Anterior supracoxale delimited from metepisternum by deep dorsal longitudinal groove, and with 3-4 anterior longitudinal grooves. Auricle (Fig. 3C) simple, elongate, pointing dorsally, terminating at half the height of the supracoxale, the apex narrow and roundedly pointed, considerably exceeding the orifice, the latter far beneath the apex. The metepimeral process (Fig. 3B; posterodorsal to supracoxale) simply rounded, kidney-shaped, delimited from metepisternum by deep, trilobate impression, and produced dorsally and posteriorly, contacting and covering the dorsolateral basis of abdomen. Ventral abdominal laterotergites (vLTG) II, III (Fig. 3A): Dorsal margins narrow, linear, clearly delimited, canaliculate, and both sharply delimited by longitudinal sulci from sternal parts of their ventrites. Basis of vLTG II overlapped by metepimeral process and contacting mesal face of the latter; the whole vLTG with very rough sculpture formed by boulderlike elevated elements forming a major irregular longitudinal groove with an indication of some subsidiary branches; overhanging mesal margin of vLTG with similar macrosculpture forming a more mesal, major groove parallel with the lateral one; all the vLTG II probably with an evaporatorial mycoid sculpture. Proximal third of vLTG III. organized as vLTG II, also with two parallel, broad grooves [the dorsal (ectal one) mesally delimited by a strong ridge] but the boulderlike sculpture limited to the mesal part; the overhang distinct only basally. Grooves and rough sculpture gradually disappearing on the second third of vLTG, the last third conforming with the more posterior vLTGs. Ventral delimitation of vLTG III from the sternum sharp and linear. Evaporatorial microsculpture limited to proximal third, if present at all. Legs (Fig. 1A): Anterior edge of ventral face of fore femur with straight or curved anteapical spine (Fig. 2F) directed diagonally distad and not longer than diameter of fore tibia. Some faces of all femora with sequence of transverse nicks (fore femur: posterior face, ca. 10; middle femur: anterior face, ca. 20; hind femur, dorsal face, ca. 15); dorsal faces of femora with a percurrent edge on each. Middle and hind femora and all tibiae unarmed. Each tibia with anterior cleaning comb, the combs on middle and hind tibiae short and not well delimited. Tarsi three-"segmented," first segment longer than second and third together (fore tarsus 1.32 times, hind tarsus 1.95 times) and with strikingly different ventral vestiture, the second tarsal segment very short. Claws slender and small, strongly and regularly curved. Forewings: Macropterous, representing ca. 70% of body length when closed (Figs. 1A, 4) slightly exceeding intersegmental sulcus VI-VII. Marginal vein (Sc?) and stem R closely apposed along anterior wing margin, fusing distad to triangular cell and forming marginal apicicorial plate (Sc&RA), projecting up to 9/10 of forewing length. Median (postradial) furrow absent. Stem Cu apposed to AA1 + 2 (both veins only separated by freely terminating claval furrow); AA3 + 4 only basally and terminally distinct, AP absent. The sclerotized apex of AA1 + 2 terminating at about end of clavus whereas apex of stem Cu turning diagonally anterodistad (as CuA?), forming a dividing vein (dividing corium from membrane); the anterior sector of the latter being met by a diagonal, posterodistally directed RP, delimiting thus a triangular corial cell. RP produced beyond the dividing vein and continuing onto membrane as a fiat sclerotized dead vein (see below). Meeting point of RP with dividing vein, point of anterior turn of Cu and corial termination of AA 1 + 2 each provided with irregularly shaped tubercle. Only the above veins are live; the dead veins are formed by membranous and usually transparent folds, as follows: Corium and clavus: (a) M arising near bases of stem R and stem Cu, and not reaching dividing vein; (b) medial part of marginal AA3 + 4 along claval margin. Membrane (c) RA forking distally, (d) RP arising from a partly sclerotized stub, (e) CuP, (f) submarginal AA. Altogether membrane with five dead veins. Hypocostal lamina forming broadproximal plate followed by narrow deflected lateral wing margin formed apparently by apposed C and Sc; the latter veins separated proximally by furrow, distally by short linear series of small pits, uniting distally; hypocostal lamina disappearing gradually along apicicorial plate. Hindwings: not examined. Mediotergal region of abdomen: mostly not examined. Abdomen (Fig. 1A): Dorsum: Mediotergites (I-III not examined) mostly fiat; IV-VI fused, their original intersegrnental sulci produced posterad, marked by positions of orifices of dorsal glands III-IV, IVV and V-VI; orifices situated much more posteriorly than relevant laterotergal intersegmental boundaries. Distal part of dorsal lateroterglte III (posterior to spiracle) and dorsal laterotergites IVVI with linear inner dorsal laterotergites. Mediotergite VII (Fig. 3D) moderately convex, narrowing caudad, posterior margin straight; ratio length: maximum width 1.35; dorsal laterotergites VII elongate and triangular, pointed, lacking inner laterotergites. Venter: Sterna II and III simple, IV strongly convex, widening and inflating distad, V-VII simple, posterior margin of VII convex, lateral margin concave, all ventral laterotergites (II-VII) distinctly delimited by sharp, linear impression (sinuated on V-VII), only the mid-part of ventral laterotergite IV fusing with sternum (laterotergal sulcus lacking). All ventrites distinct, III and IV subconnate but intersegmental line distinct; ventrite V twice as long or longer than any other (proportional lengths of ventrites II-VII approximately 7 : 9 : 15 : 30 : 11 : 12). Spiracles (1 and 2 not examined): 3 and 4 on dorsal laterotergltes, 5, 6, 7 on ventral laterotergites (in 2/3, 1/2, 1/3 of segment lengths, respectively). Trichobothria (on III and IV not examined): V 1(2) prespiracular + 2 transverse postpiracular, VI 1 prespiracular + 2 diagonal, postspiracular, the mesal one more anterior, VII 0 prespiracular + 2 postspiracular, transverse; a considerable fluctuating asymmetry in number and length:(L = long, s = short; the more mesal one of the two recorded first): V left : L + sL, right sL + ss; VI left L + Ls, right L + LL; VII left 0 + Ls, right 0 + LL. Female terminalia (Fig. 3D, E, F): Strikingly protruding, the exerted part (measured diagonally) nearly as long as abdominal segment VII, with general facies of a triangular bill with rounded apex. Dorsite VIII invisible, fully telescoped. Dorsal part of posterior foramen of segment VII, including (a) a pair of large, ventral laterotergites VIII connected by (b) an unpaired segment IX formed by a transversely rectangular sclerite (with a thin dorsal bridge and lateral arms, and a complex ventral, not fully understood ventral connective), and (c) the frame IX filled up by a large, circular proctiger including a ring-shaped segment X (c1) and bivalved segment XI (c2). The ovipositor proper relatively simple, formed by (d) unpaired, subtriangular dorsal plate with a chromatically differentiated basis (dl), a large intermediate and strongly convex major part (d2) and a depressed apical and terminally rounded part (d3), (e) paired and mutually apposed elongate ventral plates closing the complex from ventral and lateral sides, and (f) two sub-cylindrical valvular projections between (d) and (e) provided with markedly long and strong macrotrichia.
MEASUREMENTS (all in mm; L = median length, W = width, max. = maximum, med. = median, min. = minimum): Total body length: 11.2. Head: dorsal L 0.50, max. height (excl. eyes) 0.87, max. transocular W 1.67, rain. interocular W 0.93; eye, max. L 0.43, max. height 0.465, min. interocellar W 0.25, distance ocellus--eye 0.31. Antenna: total L over 10.6, L of segment 1 2.05, II 2.325, III 2.80, IV over 3.26. Labium: total L 1.05. max. length segment I 0.34, II 0.28, III 0.31, IV 0.34. Pronotum: total L 1.86; midlobe L 0.59, max. W 1.55, max. height from sternum 1.61; hindobe L 1.27, max. W 1.86, max. height from sternum 2.11. Mesoseutellum: max. W 1.03, med. L 0.51. Bifurcate pronotal process: height 0.93, span 0.93, stem height 0.465, long furcal process max. L 0.62. Fore wing (visible part), L 7.7, max. W of wings combined 1.86. Abdomen: max. ventral L 8.5, max. W 2.05; max. ventral L ventrite II 0.84, III 1.40, IV 2.80, V 1.00, VI 1.09 VII 0,75; protruding terminalia, max. lateral L 0.65. Mediotergite VII L 0.71, max. W 0.53. Fore leg, femur L 3.41. tibia L 3.10, tarsus L 1.27 (max. L segment I 0.775, II 0.185, III 0.40). Hind leg femur L 3.72, tibia L 4.03, tarsus L 1.74 dorsal L of segment I 1.14, II 0.22, III 0.37).
ETYMOLOGY: bifurcata (adj., fem.)= twice forked; according to shape of the pronotal process.
DISCUSSION
Structures surrounding antennal insertion
There is some confusion regarding the general terminology of the structures surrounding the insertion of the antenna. Both homonymical and synonymical usage abounds with anatomical terminology of insects, namely Heteroptera, such as "antennal tubercle, antennal sclerite, antennifer, antenniferous tubercle, antennal socket, torus, torulus." We apply here a simple English terminology. The antennal socket containing the articulatory antennal membrane is surrounded by a usually ring-shaped antennal sclerite provided with the antennifer--an inward articulatory projection directed towards the basis of the scape (or prescapite). The antennnal sclerite is delimited from the rest of the cranium by an antennal sulcus. All of these structures may be situated on a prominent antennal tubercle that, in some cases, may possibly be identical with an enlarged antennal sclerite.
The Colobathristinae do not have prominent antennal tubercles. Instead, the insertion of the antenna is always more or less at level with the surrounding parts of the cranium. However, the antennal sclerite, though low, is rather conspicuous and complex, and is always fragmented (Fig. 2C, D) and formed by several distinct sclerites (similar to that described for Schuhacantha). This is also true for the Dayakiellinae (PS and AE, unpublished), in which the fragments are elevated; the illustrations and descriptions by Stys (1966a) were simplified.
Breddin (1904) was the first hemipterist who noticed that the antennal sclerite ("Fuhlergrubenumrandung") of the Colobathristidae is low and complex and used the shape and length of the antennifers ("Stutzhaken der Fuhlergrube") as a diacritic character to distinguish?? between the Neotropical Colobasiastes fulvicollis Breddin, 1903 and C. analis Breddin, 1904. Stys (1966a) used differences in size of the antennal sclerite as a diagnostic character for Dayakiella species. However, the details of the structure of the antennal sclerite have remained mostly undescribed and unexploited though their prospective usage in diagnostics is indicated.
Here we offer a few preliminary functional interpretations of several structures characteristic of the Colobathristidae as revealed by the study of Schuhacantha. All our observations will be elaborated and documented in more detail elsewhere.
Enlarged antennifer and the ante-apical spine of the fore femur
All the Colobathristinae have extremely long and thin antennae and legs. The ability to maintain the integrity and control of their movements is potentially more difficult than in the most other Heteroptera. The strong spine of fore femur (Fig. 2F) in S. bifurcata, and identical or similarly situated devices in other Colobathristinae, might prevent an excessive anterad (cephalad) slip of the fore tibia relative to the fore femur, as may the size and shape of the antennifer (Fig. 2C,D) prevent an excessive mesad slip of the scape.
Pronotal process
The curiously forked pronotal process (Figs. 1C, D, 2E) may potentially function as a mechanical antipredatory device against small vertebrate predators, such as small birds, particularly if combined with chemical defense. Our personal experience (PS and AE, unpublished) with several species of pentatomoids endowed with spines, cutting edges and other such armaments shows that these structure may cause a painful immediate injury and thus potentially interrupt or stop the attack. Though any observational or experimental evidence for colobathristids is missing, this may be true for their armature as well.
Mesoscutellar spine and forewing shape
The diagonal or erect, apical or subapical, long, pointed mesoscutellar spine is characteristic of most Colobathristinae; the spine is horizontal in Dayakiellinae and only few Neotropical colobathristine genera. The defensive function of the erect spine may be the same as that of the pronotal process.
In Panheteroptera, the plesiomorphic mesoscutellum is moderately sized and triangular. The sides are co-apted with the proximal margins of clavi, with the claval margins forming a distinct postscutellar angle, and the left and right distal claval margins joining to form the claval suture. The elongate forewings of the Colobathristidae (Figs. 1A, 4) and some other Pentatomomorpha and Cimicomorpha resemble those of some more basal clades of the Heteroptera (Enicocephalomorpha, some Dipsocoromorpha, most Gerromorpha) --there is no claval angle, no claval commissure, the outlines of the forewings are smoothly elongate and the forewings overlap freely at the level of about the proximal 1/4-1/2 of the clavus. Moreover, the taxa concerned usually share tegrninal nature of forewings.
The likely apomorphic reversal of shape of the colobathristid forewings has probably co-evolved jointly with transformation of the shape of mesoscutellum. Formation of an erect mesoscutellar spine leads to a decrease in size of the mesoscutellar disc, loss of its coaptation with forewing clavi and concurrent loss of the claval commissure and claval angles that became unnecessary. The shape of the forewings can thus be reversed to a quasi-ancestral state.
The metepimeron
The metepimeron of the terrestrial infraorders of "higher" Heteroptera is usually regarded as greatly reduced to absent or part of the thoracic endoskeleton (cf. summary by Matsuda, 1970); also the posterior supracoxale is absent on the metathorax. The uniqueness of what we have called a "metepimeral process" and its contiguity with the area behind the anterior supracoxale suggests the real metepimeral nature of these structures.
Forewing venation
The forewing venation of colobathristids was studied by Stys (Dayakiella, 1966a: fig. 17; Phaenacantha, 1966b: fig. 1), and further comparative studies are in progress (or "are needed"). The important points are as follows (Fig. 4): (1) The dorsal costal edge in colobathristids is formed by two closely apposed longitudinal veins that may distally fuse to form an apicicorial plate (Dayakiella, Shuhacantha) or remain distinct (Phaenacantha). (2) A dead stem M runs in the middle of the corium, and is universally present, although this was overlooked by Stys (1966a, b) due to its transparent nature. (3) The formation of the dividing vein, triangular corial cell and stubs (terminations of corial veins transgressing over the dividing vein or over its level in case of AA1 + 2) may be diverse and may offer new diagnostic characters. (4) There are only 4-5 membrane veins, all dead, possibly with live bases in Dayakiella (cf. Stys, 1966a: fig. 17).
Female terminalia
The elements forming the bill-shaped ovipositor of Schuhacantha (and Centromus) are impossible to homologize without dissection and comparative study. They are much different from the also highly modified but still understandable plate-shaped ovipositors as described in Phaenacantha (Anorygma) and Symphylax by Stys (1974, 1977, respectively). However, we assume that the bill-shaped ovipositor seen in Schuhacantha facilitates the insertion of eggs into plant tissues or crevices, whereas the plate-shaped type is used for oviposition onto the surface of the substrate.
System of repellent secretion spread
The system of spreading repellent secretion has never been studied in colobathristids. However, the evaporatoria is clearly important for the family as it spans almost the entire mesopleuron and metapleuron. Kment et al. (2012) suggested the metathoracic spiracle is likely to play a role in spreading the secretion in terrestrial heteropterans and discussed the problems encountered by half-spherical species. We stress that analogous but opposite kinds of problems may be encountered by overly narrow heteropterans. The available space for the evolution of the evaporatoria is limited, but may be expanded by an extension of the evaporatorial areas anterad onto the mesopleuron and further as well as posterad onto the base of the abdomen. The expiration of air by the metathoracic spiracles may be assisted by wing fluttering, which must be easy in taxa with forewings shaped like those in colobathrisrids and enicocephalomorphans. The grooves observed on the basiabdominal ventral laterotergites (Fig. 3A) and their close association with the metapleuron support this interpretation. Moreover, a similar but more elaborate system of apparently fluid-carrying laterotergal abdominal grooves has been recently identified (Stys and Banar in prep.) in the Megenicocephalinae, an odd and plesiomorphic enicocephalid clade. Our assumption based on structural considerations has to be confirmed by the study of living colobathristids.
KEY TO ORIENTAL GENERA OF COLOBATHRISTIDAE
We present the following key to Oriental Colobathrisitidae to compensate for Horvath's (1904) global generic key, which is outdated and limited. Although Kormilev (1953) wrote that his key to the Oriental genera of Colobathristidae is "under printing" in Proceedings of the U.S. National Museum," to the best of our knowledge no such study was published nor mentioned in Kormilev's bibliography (Froeschner, 1995). The key to Oriental genera is intended to be easy. When counting abdominal ventrites, note that ventrite I is not developed and that some more distal ventrites can be fused ("connate" is a term customarily used). Only the genera Symphylax and Phaenacantha are species-rich; all other genera (11) contain no more than three species each. The names of species classified in monotypic genera (8) are given in parentheses as well as ranges of the genera and subgenera. F and M indicate that females and/or males have been described, respectively.
1 (2) Extremities short and moderately thick. Antennae half as long as the body, scape shorter than transocular width. Mesoscutellar spine horizontal. Left and right abdominal laterotergites VII mutually fused posteriorly; enclosing thus a genito-anal chamber; (Java, Borneo); M, F. DAYAKIELLINAE Stys, 1966 Dayakiella Horvath, 1922
2 (1) Extremities strikingly long and extremely thin. Antennae at least subequal to the length of the body, scape longer than transocular width. Mesoscutellar spine diagonal to vertical. Left and right abdominal laterotergites VII mutually free; no genito-anal chamber present. COLOBATHRISTINAE Stad, 1865
3 (22) Corium with an apical triangular cell adjoining the costal margin.
4 (7) Pronotum armed with spine(s). Ovipositor acutely protruding, bill-shaped.
5 (6) Midlobe of pronotum simple, hindlobe with two simple humeral spines. Labium nearly surpassing fore coxae; C. trispinosus Bergroth, 1910 (Malaysia:Sarawak); F Centromus Bergroth, 1910
6 (5) Midlobe of pronotum with an unpaired double-forked spine, hindlobe simple. Labium extremely short, slightly exceeding collum of prothorax; S. bifurcata sp.n. (peninsular Malaysia); F Schuhacantha gen. n.
7 (4) Pronotum unarmed. Ovipositor concealed within segment VII or only slightly protruding, plate-shaped.
8 (11) Ocelli widely separate, interocellar distance equal to distance from ocellus to eye or longer.
9 (10) Eyes slightly stylate. Interocellar distance longer than distance from ocellus to eye. Labium not exceeding fore coxae. Fore femur with two subapical spines; (Philippine Is); M, F Diplodontella Horvath, 1922
10 (9) Eyes sessile. Interocellar distance equal to distance from ocellus to eye. Labium reaching middle of mesosternum. Fore femur with one subapical spine; E. bergrothi Horvath, 1922 (Malaysia: Sabah); F Elopura Horvath, 1922
11 (8) Interocellar distance shorter than distance from ocellus to eye.
12 (15) Some abdominal ventrites (either III/IV or IV/V) fused. Labium reaching middle of mesosternum or less.
13 (14) Ventrites III and IV fused. Ocelli subcontiguous; P. tipuliformis Kormilev, 1953 (Java); M, F Paraelopura Kormilev, 1953
14 (13) Ventrites IV and V fused. Ocelli widely separated; N. geniculata (Stal, 1870) (Philippine Is); F Narcegaster Horwith, 1904
15 (12) All ventrites free. Labium reaching middle of mesosternum or beyond.
16 (17) Eyes weakly stylate. Labium reaching middle of mesosternum; T. robustum (Breddin, 1903) (Buton I.); F Taphrocranum Horvath, 1904
17 (16) Eyes sessile. Labium reaching middle coxae or beyond.
18 (19) Midlobe of pronotum gibbous, strikingly higher than head; (New Guinea); M, F. Brachyphyma Horvath, 1904
19 (18) Midlobe of pronotum not gibbous.
20 (21) Distance from ocellus to eye twice as long as interocellar distance or more; (Oriental) M, F Symphylax Horvath, 1904
21 (20) Distance from ocellus to eye only slightly longer than interocellar distance; M. horvathi Bergroth, 1910 (Malaysia: Sarawak); F. Molybditis Bergroth, 1910
22 (3) Corium lacking an apical triangular cell adjoining the costal margin.
23 (24) Posterior lobe of pronotum with an erect discal spine; D. notabilis Horvath, 1922 (Philippine Is); M Discocentrus Horvath, 1922
24 (23) Posterior lobe of pronotum without a spine. Phaenacantha Horvath, 1904
25 (26) A median unpaired sulcus or a foveole present in front of the ocelli; (Oriental, Philippine Is., Moluccas, New Guinea, Fiji, Australia: Queensland); M, F Phaenacantha subg. Phaenacantha
26 (25) A pair of closely approached linear impressions present in front of the ocelli; (Oriental, E Palaearctic, Philippine Is; Guatemala?); M, F Phaenacantha subg. Anorygma Horvath, 1904
Horvath (1904) did not fix the type species of Anorygma. The type species of Anorygma is Colobathristes saccharicida Karsch, 1874 = Phaenacantha (Anorygma) saecharicida (Karsch, 1874) as subsequently designated by Stys (1974: 226). Kerzhner (2001: 243) was not aware of that fixation and invalidly designated type species for Anorygma. Fortunately, it was the same type species as Stys (1974).
Anorygma Horvath, 1904 = Phaenacantha subgenus Tagalisea Horvath, 1904 (type species Colobathristes pallidus Stal, 1870, by monotypy), junior subjective synonym; synonymy substantiated by Stys (1974) acting as a first reviser.
ACKNOWLEDGEMENTS
We acknowledge the support of the Czech Science Foundation grant (P505/11/1459) to AE and PS, and Synthesys 2 AT-TAF 1315 project (Colobathristidae (Hemiptera: Heteroptera of the World: Systematics, Morphology, Biogeography) granted to PS. For a kind assistance while working in the Department of Entomology, Naturhistorisches Museum, Wien, Austria, we are grateful to Herbert Zettel and Harald Bruckner, who also took the photographs. Our manuscript has been considerably improved by reviews of Thomas Henry, Christine Johnson and an anonymous reviewer.
LITERATURE CITED
Breddin, G. 1904. Noch einiges uber Colobasiastes Bredd. (Rhynchota heteroptera). Wiener Entomologische Zeitung 23: 245-250.
Froeschner, R. C. 1995. Nicholas A. Kormilev: A list of his entomological publications and proposed taxa. Proceedings of the Entomological Society of Washington 97: 515-554.
Hovath, G. 1904. Monographia Colobathristinarum. Annales Musei Nationalis Hungarici 2:117-172.
Horvath, G. 1916. Colobathristidarum species nova. Annales Musei Nationalis Hungarici 14: 422.
Horvath, G. 1922. Colobathristidae novae in Musei nationali himgarico. Annales Musei Nationalis Hungarici 19: 154-160.
Hsiao, T. Y. 1977. Colobathristidae, pp. 288 290, 305 in T. Y. Hsiao, et al. A Handbook for the Determination of the Chinese Hemiptera-Heteroptera. Vol. I. Science Press, Beijing (in Chinese, English summary).
Kerzhner, I. M. 2001. Family Colobathristidae Still, 1865, pp. 243-245 in B. Aukema and C. Rieger (eds.), Catalogue of the Heteroptera of the Palaearctic Region. Vol. 4. Pentatomomorpha I. Netherlands Entomological Society, Amsterdam.
Kment, P., P. Stys and J. Vilimova. 2012. Thoracic scent efferent system and exponium of Aphylidae (Hemiptera: Heteroptera: Pentatomoidea), its architecture and function. European Journal of Entomology 109: 267-279.
Kormilev, N. A. 1951. Notas sobre "Colobathristidae" neotropicales (Hemiptera), con la descripcion de tres generos y siette especies nuevas. Revista Brasileira de Biologia 11: 63-84.
Kormilev, N. A. 1953. Notes on Colobathristidae from Borneo and Java in the collections of the Museum of Natural History in Basle (Hemiptera). Mitteilungen der Schweizerischen Entomologisehen Gesellschaft 26: 287-292.
Matsuda, R. 1970. Morphology and evolution of the insect thorax. Memoirs of the Entomological Society of Canada 76: 1-431.
Stys, P. 1966a. Revision of the genus Dayakiella Horv. and notes on its systematic position (Heteroptera: Colobathristidae). Acta Entomologica Bohemoslovaca 63:27-39.
Stys, P. 1966b. Morphology of the wings, abdomen and genitalia of Phaenacantha australiae Kirk. (Heteroptera, Colobathristidae) and notes on the phylogeny of the family. Acta Entomologica Bohemoslovaca 63: 266-280.
Stys, P. 1974. A Synopsis of the genus Phaenacantha Horv., I. Subgenus Anorygma Horv. (= Tagalisca Horv.) (Heteroptera, Colobathristidae). Annales Historico-Naturales Musei Nationalis Hungarici 66: 225-234.
Stys, P. 1977. Revision of Symphylax (Heteroptera: Colobathristidae). Acta Zoologica Academiae Scientiarum Hungaricae 23: 427-451.
PAVEL STYS AND ALICE EXNEROVA
Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic, e-mail: [email protected], [email protected]
(1) Kormilev (1951) described Phaenacantha (Anorygma) saileri Kormilev, 1951, based on a single male from Guatemala (no further data; leg. D.C.Eisen; M holotype in coll. U.S. National Museum, Washington). Because no genus of the family is known from both the Eastern and Western Hemispheres, Stys (1974) discussed and doubted the natural occurrence of Kormilev's species in Guatemala in the subgenus Anorygma. However, the classification and distinctness of the species had not been challenged and was subsequently confirmed by examination of the holotype in 1990. Phaenacantha saileri had been most likely introduced to Guatemala from an unknown Oriental site or the holotype was accidentally mislabelled.
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| Author: | Stys, Pavel; Exnerova, Alice |
|---|---|
| Publication: | Entomologica Americana |
| Article Type: | Report |
| Geographic Code: | 9MALA |
| Date: | Jan 1, 2012 |
| Words: | 6603 |
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