Triangulara Pimpasalee

Ballantyne, Lesley A., Lambkin, Christine L., Luan, Xin, Boontop, Yuvarin, Nak-Eiam, Sorasak, Pimpasalee, Suttisan, Silalom, Sommyot & Thancharoen, Anchana, 2016, Further studies on south eastern Asian Luciolinae: 1. Sclerotia Ballantyne, a new genus of fireflies with back swimming larvae 2. Triangulara Pimpasalee, a new genus from Thailand (Coleoptera: Lampyridae), Zootaxa 4170 (2), pp. 201-249 : 238-242

Triangulara Pimpasalee gen. nov.

( Figs 139 −151)

Type species. Triangulara frontoflava Pimpasalee sp. nov., by monotypy.

A description of a new genus and new species of fireflies from Thailand further highlights several of the taxonomic problems facing workers in this subfamily.

The first is the problem of identification. While Thailand is recognised as a biodiversity ‘hotspot’ ( Brooks et al. 2002), the only recent survey of firefly species in Thailand indicated 15 species in seven genera ( Hutacharern et al. 2007) (see Table 5). Such surveys especially in Thailand and other areas of SE Asia rely on previous catalogues and little on results of new fieldwork and collections (Ballantyne 2012). Thus mistakes and misinformation are perpetuated and the seven Luciolinae species in this list are reassessed below in Table 5.

Species Comments

Luciola brahmina Bourgeois 1890 %* Occurs in Thailand but was confused for years with a species subsequently described as L. aquatilis Thancharoen (Thancharoen et al. 2007) . Identity and range assessed here.

Luciola cruciata Motschulsky 1854 Not confirmed in Thailand

Luciola ovalis ( Hope 1831) Incorrect identification; confirmed as Asymmetricata circumdata (Motsch.)

by LB (see Ballantyne & Lambkin 2009)

Luciola substriata Gorham 1880 #* Identity and range addressed here

Pteroptyx malaccae ( Gorham 1880) # Identification confirmed by LB

Pteroptyx valida Olivier 1909 # Identification confirmed by AL

Pyrophanes indica ( Motschulsky 1854) Luciola indica incorrectly assigned to Pyrophanes by McDermott 1966 (Ballantyne & Lambkin 2013: 111); Ballantyne et al. (2015) assigned this species to a new genus Inflata Boontop

Many Luciolinae species (like the species described here) share the same colour patterns and often very similar external morphology. Examination of type material using external morphology only is often inadequate. Ballantyne & Lambkin (2009) indicated the importance of examination of, and if possible, dissection of, types, in any exercise involving these similarly coloured species. Thancharoen et al. (2007) discussed the problems that arose with their attempts to reliably identify a common species from Thailand which they eventually described as Luciola aquatilis . We faced the same problems here.

This large and distinctive firefly, first found by LB in the collections at Kasetsart University among specimens of L. aquatilis / L. substriata , and in NHML among specimens of Luciola cingulata Olivier , was distinguished initially by Ballantyne by dissection. It was scored in Fu et al. (2012a) as undescribed Thailand ‘species 8’ and distinguished in their Fig. 8 node 44, blue number 20 as Species 8, and in Ballantyne & Lambkin (2013) in Fig. 4 node 44 as Species 8.

Diagnosis. Triangulara gen. nov. belongs to a group of SE Asian Luciolinae which have a pale coloured dorsal surface (including a pale pronotum), with black tipped elytral apices. In the male the aedeagal LL are visible beside the ML when viewed from beneath. Males are most obviously distinguished from Sclerotia gen. nov. by the triangular outline of the LO in V7, no anteromedian emargination of the V7 LO, and no sclerites surrounding the aedeagal sheath (In Sclerotia gen. nov. the LO may occupy all of V7, or may appear heart shaped, with an anterior median emargination often so deep that the LO appears U shaped; a set of 3 sclerites surround the posterior area of the aedeagal sheath). It is distinguished from the similarly coloured Abscondita Ballantyne most obviously by the triangular shape of both the LO and V7, the separation of the aedeagal LL along most of their dorsal length and the absence of bulbous projections from the lateral margins of the LL (n Abscondita the LO in V7 occupies most if not all the area of V7 which is broadly rounded behind and often very flat; the LL are fused along almost all of their dorsal length, and bulbous projections arise from the lateral margins of the LL). Confused in collections with Luciola aquatilis and L. substriata Gorham which are assigned here to Sclerotia gen. nov. Female macropterous and coloured as for male except for pale terminal ventrites 6 and 7. Larva unknown but preliminary observations by Pimpasalee indicate it may be aquatic.

Male. BL/ W 2.9 –3.0. Colour: dorsally yellow with elytral apices black. Pronotum: W/L 1.8–2.0; L/BL 0.16– 0.17; W/GHW 1.4–1.5; dorsal surface without irregularities in posterolateral areas and longitudinal groove in lateral areas (1, 2); punctation dense; anterior margin not explanate; not subparallel-sided; pronotal width subequal to humeral width; anterolateral corners rounded obtuse; lateral margins divergent posteriorly, often with rounded convergence before posterolateral corners; lateral margins without indentation at mid-point (15), or sinuousity in either horizontal or vertical plane (16); without indentation in lateral margin near posterolateral corner, and irregularities at corner (17, 18); posterolateral corners rounded obtuse; posterolateral corners projecting as far as median posterior margin or slightly beyond, and separated from it by shallow emarginations; median posterior margin widely and very shallowly emarginated or not; most of dorsal surface appears slightly convex; without depressed areas except anterior to posterior emarginations.

Hypomera: closed; median area of hypomeron not elevated in vertical direction; anterior area of hypomeron not flat, posterior area flattened only at corner and not closely adpressed.

Elytron ( Fig. 139 ): EL/BL 0.8; subparallel-sided in anterior 2/3; punctation dense, linear in some areas close to suture, not linear over rest of surface, not as large as that of pronotum, nor widely and evenly spaced (34); apices not deflexed; epipleuron and suture extend beyond mid-point, almost to apex but not as ridge around apex, neither thickened in apical half; interstitial lines barely visible; elytral carina absent (54); in horizontal specimen viewed from below epipleuron at elytral base wide, covering humerus or almost so, viewed from above epipleuron arises anterior to posterior margin of MS; epipleuron developed as a lateral ridge along most of length; sutural margins approximate along most of length in closed elytra.

Head ( Figs 140, 144 ): SIW/GHW 0.15–0.16; not deeply depressed between eyes; well exposed in front of pronotum, not capable of complete retraction within prothoracic cavity; eyes moderately separated beneath at level of posterior margin of mouthpart complex; eyes above labrum moderately separated; frons-vertex junction rounded, without median elevation; posterolateral eye excavation not strongly developed, not visible in resting head position (61); antennal sockets on head between eyes, not contiguous, separated by less than ASW; clypeolabral suture present, flexible, not in front of anterior eye margin when head viewed with labrum horizontal; outer edges of labrum reach inner edges of closed mandibles. Mouthparts: functional; apical segment of labial palpi strongly flattened, of form of wide triangle, with inner edge dentate (3 or more teeth; dentition may differ from R to L palpomere in the one individual). Antennae: 11 segmented; length>GHW to <twice GHW; no segments flattened, shortened, or expanded; pedicel not produced; FS1 approximately twice as long as pedicel; all FS elongate slender about 4 times as long as wide.

Legs ( Figs 139, 140 ): with inner tarsal claw not split; without MFC (96); no femora or tibiae swollen or curved; no basitarsi expanded or excavated (97−104).

Abdomen ( Fig. 140 ): without cuticular remnants (sclerites) in association with aedeagal sheath; no ventrites with curved posterior margins nor extending anteriorly into emarginated posterior margin of anterior segment. V6: LO occupying all of V6. V7: longer than wide and triangular in outline, with posterior margin narrow and rounded; LO in V7 triangular in outline, entire and occupying more than half area, not reaching to sides or posterior margin and margins following outline of V7; LO reaching into MPP; LO laterally margined by a distinct longitudinal groove; areas at sides of LO slightly rounded; posterior area behind LO not arched or swollen, muscle impressions not visible in this area; neither anterior nor posterior margin of LO emarginate; MPP present, symmetrical, apex rounded, entire, not laterally compressed, L=W or L>W, sometimes inclined slightly dorsally when it may be partially covered by slightly downturned T8 apex; if MPP L>W then it usually extends beyond the posterior margin of T8; MPP without dorsal ridge, median longitudinal trough; V7 without median carina, median longitudinal trough, anteromedian depression on face of LO, PLP, incurving lobes or pointed projections, median ‘dimple’, or reflexed lobes. T7: without prolonged posterolateral corners. T8: strongly sclerotised, symmetrical, longer than wide, visible posterior area subparallel-sided along anterior half or more in pinned specimens, not narrowing abruptly towards posterior end but lateral margins may converge gently in softened specimens prepared for dissection, without prolonged posterolateral corners, median posterior emargination, median posterior projections, often inclining weakly ventrally and sometimes partially engulfing posterior margin of MPP, not extending conspicuously beyond posterior margin of V7; T8 ventral surface without flanges, lateral depressed troughs, median longitudinal trough (traces of a trough can be seen in softened specimens), asymmetrical projections, median posterior ridge; concealed anterolateral arms of T8 as long as or longer than posterior entire portion, not laterally emarginated before their origins, narrow and slightly expanded dorsoventrally, without bifurcation of inner margin and ventrally directed pieces; lateral margins of T8 not enfolding sides of V7.

Aedeagal sheath ( Figs 141, 146 ): approximately 3 X as long as wide; without paraprocts (250); asymmetrical in posterior area with sheath sternite emarginated on right from point of attachment of tergite and narrowing to an acute apex; sternite not angulate on L or R sides, not subparallel-sided, posterior margin very narrow, irregular; anterior half of sternite broad, apically rounded; tergite without lateral arms extending anteriorly at sides of sheath sternite; tergite not subdivided, without projecting pieces along posterior margin of tergite 9, anterior margin without transverse band, evenly and shallowly emarginated ( Fig. 141 ).

Aedeagus ( Figs 147, 148 ): asymmetrical due to asymmetry of apex of ML which bends to one side, and the differing shapes and inclinations of the LL; L/W slightly less than 3/1; lateral margins of LL not subparallel-sided; LL lack lateral appendages; LL visible from beneath at sides of ML, LL/ML wide to moderate; depending on orientation of aedeagus LL are not of equal length, are slightly shorter than ML, diverging along inner dorsal margins along apical half, and slightly separated at their base; LL base width not=LL apex width which is narrower than that of ML; apices of right LL expanded slightly more than that of left; dorsal base of LL symmetrical, median anterior margin of LL strongly prolonged and rounded with its outline following that of the inner margin of the BP; LL without lateral hairy appendages along their outer ventral margins, not produced preapically nor narrowly on inner apical margin; apex of left LL out–turned; inner margins without slender leaf-like projection; ML asymmetrical and bending at its apex slightly to the left; without paired lateral teeth and tooth to left side, not strongly arched, apex not shaped like arrowhead, not bulbous, not inclined ventrally; BP not strongly sclerotised, not hooded, not strongly emarginated along anterior margin, elongate (slightly less than half as long as aedeagus) with anterior margin truncate; lateral margins of BP project posteriorly for slightly less than half the aedeagal length.

Female ( Figs 142, 143, 145 , 149 ). Macropterous, not observed in flight. Pronotum: without irregularities in posterolateral areas; punctation moderate to dense; width subequal to humeral width; without indentation of lateral margin, irregularities at posterolateral corner; outline similar to that of male. Elytral punctation not as large as that of pronotum, nor evenly spaced; elytral carina absent. No legs or parts thereof swollen and/or curved. LO in V6 only, without any elevations or depressions or ridges on V7; median posterior margin of V7 squarely truncated, V8 broadly rounded across posterior margin and scarcely projecting posteriorly beyond the acute lateral projections of V7 posterior margin. No bursa plates. Female reproductive anatomy not further investigated here.

Larva. Unknown (however see discussion).

Etymology. The generic name is latinised from the English word triangular and refers to the distinctive shape of both V7 and the V7 light organ in males; Triangulara gen. nov. is to be regarded as a feminine singular noun.

Figures

FIGURES 139 − 146. Triangulara frontoflava gen. et sp. nov. paratypes (CUMZ). 139, 140 141, 144 male; 142, 143, 145 female. 139, 142 dorsal; 140, 143 ventral; 141, 146 aedeagal sheath dorsal (141) and ventral (146); 144, 145 head anterior.

FIGURES 4 − 12. Luciolinae Table 3. 4 − 6 Luciola ambita male (MNHN). 7 − 9 Luciola delauneyi male (MNHN). 10 − 12 Luciola flebilis female (MNHN). 4, 7, 10 specimen label; 5, 9, ventral (9 abdomen only); 6, 8, 11 dorsal (6 anterior body only; 8 elytra only); 12 right lateral. Scale line is 1 mm. Figs 6, 8, 9, 11, 12 are not to scale.

FIGURES 147 − 149. Triangulara frontoflava gen. et sp. nov. paratypes (CUMZ). 147, 148 male aedeagus ventral (147) and dorsal (148); 149 mating pair male to left. 150 − 151 pond weed with eggs of Triangulara frontoflava gen. et sp. nov.