Heliocypha biseriata
Creators: name: Orr, Albert G. W.
name: Dow, Rory A.
name: Steinhoff, Philip O. M.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Odonata
Chlorocyphidae
Heliocypha
Heliocypha biseriata

description: Heliocypha biseriata (Selys)
(Figs 4a, 5a, 6a, b, d, e, 7a, 8a, 9a, 10a, b, c, 12a, b, e, 13a–g, 16a, d, 18a)
Material examined. MALAYSIA, 2 ♀♀ F (RMNH. INS.557684, RMNH. INS.557685), Sungai Datai and tributaries, Lanjak Entimau Wildlife Sanctuary, Kapit Division, Sarawak, 1.6493N, 112.2627E, 22 viii 2013, leg. A. Pasang.
Habitus: small larva, squat body with long, thin banded legs and mottled pattern on the body and appendages (Fig. 4a); sagittate head; scape slightly less than half total length of antennae, pedicel with dark tip; lateral caudal gills form two rapier like tapered spikes with numerous short backward pointing spines and setae; central cone-like epiproct represents the vestigial median gill.
Head: in dorsal view rounded pentagonal, ca 5/6 th as long as broad, with occipital hind margin deeply excavated, producing overall sagittate outline (Fig. 5a), frontoclypeus smooth. Antennae 7-segmented (Fig. 5a); scape long and thick, about 2/5 th length of entire antenna with basal and apical markings, bearing short fine, curved setae, often recurved to touch integument (Fig. 6b), which create a warty appearance when wet (but not submerged) as they trap droplets of fluid held by surface tension; pedicel with distinct dark mark on apex; bearing sparse long setae; remaining segments thin and pale. Labrum (Fig. 6a) broadly curved with distinct dorsal and ventral parts, the latter boomerang shaped, the two parts meeting along thickened anterior ridge bearing small tubercles laterally; ventral part with median row of 12–13 ventrally directed strong setae, forming distinctive ‘moustache’, patches of shorter setae mid-ventrally and tufts of long fine setae towards corners; entire labrum forms a curved cavity into which anterior half of mandibles fit on either side. Vertex with three smooth swellings representing ocelli; eyes irregularly trapezoidal and prominent occupying outer 1/3 rd of lateral part of head but compound facets restricted to two small globular areas at the outer corners, clearly demarked by an anterior groove (Figs 5a, 7a); postocular lobes with prominent dorsolateral tubercle anterior to the posterior corner. Dorsal surface of head, excluding vertex scattered with small sparse low warty structures extending even onto inner marginal areas of eyes; antennal sockets swollen, with sparse long, fine setae laterally. Ventrally, genae bear a cluster of short heavy subocular spines, with one strong row dorsally, the anterior 2–3 acuminate, the remainder rounded, and below this a sparse irregular scattering of shorter rounded tubercles clearly visible in lateral and ventral view (Fig. 7a); postocular lobes with ventrolateral cluster of weakly developed spines and setae; strong ventral spur at margin of gena and occiput. Mask long and thin, articulation resting between anterior part of coxae of mesothorax (Fig. 8a); prementum narrow basally, gradually flared anteriorly with margins of anterior half weakly convex; lateral margins with sparse fine setae on distal 2/3 rd (Fig. 9a) anterior median lobe weakly convex with coarsely serrate margins; median cleft open and moderately deep with small nearly circular aperture at base (Fig. 10a); Lobe of labial palp bifid (Figs 10a–c), with dorsal process a long claw bearing secondary dorsal hook and ventral process a shorter claw with small interior beak like process; inner margin of lobe with fine sparse denticulations evident even on the inner process; movable hook stout, moderately long and curved especially in apical half. Maxillae as shown (Figs 12a–b, 12e); galeolacinea with four long strong teeth towards apex curved orally; apical tooth with row of three inner broad-based supplementary denticles (Fig. 12e), basal pair partially fused at base, longest one apicad; row of ca 5 strong setae along low ridge aligned with apical tooth; long fine setae present on internal margin of galeolacinea; palp tapering, not reaching tip of apical tooth, bearing long strong setae in all outward directions. Mandibles (Figs 13a–f)—both left and right with five distinct teeth on incisor visible in external view (Figs 13a, b); in inner view (Fig. 13c) right incisor lobe with four long teeth and one shorter one between fourth and fifth one ventrally and small supplementary tooth basal to strong ventral tooth; molar crest a low swelling with two small nipple-like points, lightly sclerotised (Fig. 13c, e); left incisor (Fig. 13d, f) with six teeth, the third from the dorsal being vestigial and only visible on inner face, pronounced gap between first and second teeth from ventral; molar crest bearing strong rounded cupped blade (Fig. 13d) with nine minute denticles along roughly straight distal margin (Fig. 13g). Single strong seta at exterior basal corner on each mandible (Fig. 13d), not always visible, depending on angle of view.
Thorax: prothorax saddle-shaped with narrow flange anteriorly fitted into occipital margin; dorsum with transverse central groove; two pairs of prominent broad tubercles, a central pair just behind groove and a lateral pair posterior to these and close to ends of posterior flange that curves broadly around posterior margin (Fig. 5a). Propleura swollen with small anterior ventral truncated spur, well ahead of coxae. Remainer of thorax with shallow grooves and bulges; entire dorsum of thorax with sparse fine warty texture, as on head, and with sparse long, fine setae collapsed in preserved specimens. Marking (not illustrated on body) variable and mottled but always with broad pale band pale between two anterior tubercles on prothorax. Wing sheaths slightly spatulate, not completely obscuring abdomen at sides, forewing reaching to end of S4, hindwing to 3/4 along S5 (Fig. 4a). Legs long and thin, metafemur reaching end of S7; femora all with three distinct evenly spaced dark bands on ochreous ground colour, with tiny dark mark at base sometimes also on trochanter; all femora with anterior ridge bearing very small outward directed spines, some bearing setae, and sparse fine setae towards tibial joint, some quite long; tibiae unmarked or with single basal darker band, with fairly sparse setae, mainly fine and straight but some stronger and curled, longer denser ventral patch of straight setae apically; tarsus (Figs 6d, e) bearing two rows each of ca 25 strong, tapering pectinate setae (Fig. 6e). Tarsal claws simple.
Abdomen: squat, mainly dark with well-defined pale narrow middorsal stripe (not figured). Laterally with patches of small spine like setae and mixture of curved and fine long setae; each segment from S4 with submarginal row of small ventral spines; ventrolateral margin of S9 with 4–5 strong, long spines intermingled with 4–5 smaller spines partly placed a little above margin and four strong spines along ventral margin; S10 hind-margin with 4 strong rearward pointing ventrolateral spines and 3 long spines extending to lateral hind-margins, smaller spines along ventral hind margin and on venter (Figs 16a, d). Outer female gonapophyses arising from base of S9 and extending well beyond hind margin of S10 (Fig. 16a), ventral margin with series of sparse heavy spines and terminating in a single long heavy spine deflected ventrally in lateral view (Fig. 16d); inner apophyses smooth, curved smoothly upward to a rounded point extending well beyond outer apophyses and epiproct. Male gonapophyses unknown. Epiproct, short, subconical, in shape of elongated onion dome. Caudal spikes long, about 55% body length, broad basally and from just before midpoint tapered gradually and smoothly to a sharp point (Fig. 18a); bearing numerous backwardly curved strong sharp spines, heavy setae, and also long fine setae too entangled to assess accurately.
Measurements (in mm): body length excluding antennae, caudal appendages and spikes 11.8; lateral caudal spikes 6.5; head width 2.7; prementum 2.65; palpal lobe (to tip of dorsal branch) 0.85; movable hook 0.72; maxillae base to distal hook of galeolacinea (1.24), maxillary palp (0.54); mandibles long axis (0.85); antenna 1.70, 0.65, 0.70, 0.50, 0.28, 0.19, 0.10 (total 4.11).
Variation: outwardly no noticeable variation, other than minor differences in the mottling on the head, in the numbers of large setae in the ‘moustache’ of the labrum, and in the number of spines present on S9 and S10, was evident in the two female specimens examined. The unusual dentition of the mandibles differed slightly in the two specimens examined in that in the second specimen (not illustrated) the vestigial inner tooth at the base of the 2 nd and 3 rd incisor teeth from the dorsal is minute, no more than 15 μm long. No significant differences were evident in the male specimen photographed in some detail by POMS; no image was made of the gonapophyses hence these cannot be described, but they are unlikely to present useful diagnostic characters.
Remarks
While unusual characteristics of the mouthparts, especially the dentition of the mandibles appear to be consistent it is possible that the inner vestigial left incisor tooth is entirely lacking in some specimens. The labrum, while similar in other species examined (see below), is unique among odonates and is probably an autapomorphy for the family. Pectinate setae confined to tarsi, previously recorded by Kumar (1973) and Kumar & Prasad (1977), are another probable family apomorphy.
Two other species of Heliocypha larvae have been described in some detail: H. biforata (as H. biforata beesoni, now considered a synonym of H. biforata biforata), by Kumar & Prasad (1977) and H. p. perforata by Xu (2015). The drawing of the antenna in the former paper depicts the scape as 0.33 times the overall length of the antenna, but by the measurements given in the text and the depiction of the antennae on the habitus drawing this proportion should be 0.42, which is very close to the other species considered, hence the detailed drawing itself must be regarded as a lapsus, perhaps because it was inadvertently observed at an angle. The authors do not comment on an obviously relatively short scape. They also illustrate the scape with a rough warty texture, but in H. biseriata it was found that these apparent structures were an illusion (seemingly present in photographs taken independently by AGWO and POMS) created by short recurved setae trapping fluid in wet specimens and giving the appearance of small tubercles where none were present. The shape of the prementum in H. biforata, although basically similar, differs from that of H. biseriata in being relatively shorter, and the anterior median lobe is strongly convex with only a small notch representing the median cleft. The subocular spines on the gena appear very similar. Similarly, in H. p. perforata the prementum is relatively shorter than in H. biseriata but is otherwise very similar. There are also strong similarities in the female genital apophyses. The depiction of the labial palp by Xu (2015) is erroneous, as it omits the secondary upper branch of the palpal lobe, a structure clearly evident in photographs of this species (Ng 2024). However both Kumar & Prasad (1977) and Xu (2015) depict the caudal spikes of H. biforata and H. perforata respectively and they are very similar in form to those of H. biseriata, being rather heavy and tapering gradually to a point from around the midpoint (in this respect the drawing by Xu 2015 is misleading, but this character can clearly be seen in the habitus photograph provided). The spikes are relatively long in H. perforata (ca 55% body length) but are figured as shorter in H. bisignata (ca 46% body length) depicted by Fraser (1928) and later briefly described by the same author (Fraser 1934).Although lacking subtlety, the 1928 illustration agrees quite well with other Heliocypha species, especially in the form of the caudal spikes. Neither Xu (2015) nor Ng (2024) examine the subocular spines on the gena, of H. perforata but it seems these, and the form of the caudal spikes, may be characteristic of the genus. Both H. biforata and H. perforata also have long legs, with the metafemur reaching the hind margin of S 7 in F stadium larvae. The depiction of the prementum and labial palps of H. fenestrata by Lieftinck (1962), is very reminiscent of H. biseriata but the habitus drawing does not depict the caudal spikes convincingly. This, and the style, strongly suggest the drawing was executed by a Bogor Museum staff member such as G. Abdulkadir rather than Lieftinck himself (see van Tol 1992), and it is well known that many such drawings are more decorative than accurate.
description: Published as part of Orr, Albert G. W., Dow, Rory A. & Steinhoff, Philip O. M., 2024, Descriptions of larvae of four mainly DNA barcode-matched species of chlorocyphids from south-east Asia (Odonata: Chlorocyphidae) with notes on the generic and species level larval identification of Oriental region members of the family., pp. 301-337 in Zootaxa 5486 (3) on pages 307-314, DOI: 10.11646/zootaxa.5486.3.1, http://zenodo.org/record/13210005