Diaphanes pectinealis Li & Liang

Li, Xueyan & Liang, Xingcai, 2007, A new species of the genus Diaphanes Motschulsky (Coleoptera: Lampyridae) from Gaoligong Mountains of Yunnan, Southwest China, Zootaxa 1533, pp. 53-61 : 54-59

Diaphanes pectinealis Li & Liang , new species

( Figs. 1 –3, 6–8, 10–16)

Description. MALE ( Figs. 1 –3, 7, 10, 12–16), BL 16.5–18.6 mm; BW 5.6–7.0 mm. Body ( Fig. 1 ) elongate, depressed dorsally. Coloration pale grayish brown; head black; pronotal disc, prosternum and mesosternum, hypomera vivid red but fading in dried or alcohol specimens ( Figs. 1 , 2 ); the remaining part of pronotum, scutellum, elytra pale grayish brown but with black markings at the base of elytra; antennae, femora to tarsi in pro- and mid-legs, entire hind legs, metasternum, ventrites 1–4 and non-luminous regions of ventrites 5–6 black; ventrite 7 and pygidium pale yellow. Head 0.45–0.53 times as wide as pronotum. Antenna (Fig. 10) pectinate, almost as long as 1/2 body length; 1st antennomere cone-shaped; 2nd very short, cylindrical, only 1/4 as long as 3rd one; 3–10th compressed, with branches originating from entire segment; branch of 3rd antennomere short, triangular, 4–10th with long branches; 11th almost twice as long as the proceeding segment, gradually dilated from base to apex, with asymmetrical bimucronate appendage at apex; antennal sockets broadly separated from each other. Eyes large, weakly reniform laterally; interspace between eyes almost uniformly wide from frons to ventral angle, about 0.23–0.27 times as wide as head width. Clypeus and labrum fused together, elongate oval. Mandibles a little shorter than clypeus+labrum. Maxillary palpi (Fig. 12) with M2 longest and M3 shortest, M4 brief but with a conspicuous flat rim on inner margin. Labial palpi (Fig. 13) small, with L3 pointed at apex. Pronotum semi-elliptical (PW/PL= 1.4–1.5); apical and lateral margins moderately elevated; longitudinal carina distinct; lamp area translucent and densely punctuate, with areolet areas large and clear. Scutellum ligulate and covered with brown hairs. Elytra elongate, subparallel or broadest in apical 2/3. Legs long and slender; 1st tarsomere as long as 2nd+3rd tarsomeres of all legs (Fig. 14). Abdominal terga shorter than elytra; apicolateral angles of terga acute; pygidium trisinuate, with middle lobe either shorter or as long as lateral ones; photic organs (Fig. 7) on apical 1/2 of ventrites 5 and 6, respectively; ventrite 7 (Fig. 7) emarginate. Abdominal spiracles on lateral edges of each abdominal segments. EL/EW= 2.14–2.47; EL/PL=4.17–5.00.

Aedeagal sheath (Fig. 15) about 2.3 mm long, covering dorsal and left lateral side of male genitalia. TS subtrapezoidal, with base broadly rounded; T9 round apically; T10 a little longer than T9, trapezoidal, with apex truncate and slightly surpassing S9; S9 elongate, moderately asymmetrical. Aedeagus (Figs. 16a, b, c) about 1.88 mm long, typically trilobate in form. Median lobe slender, broadest at base, becoming narrower in apical 1/2, then elliptically expanding and becoming narrower near apex and then dilated weakly at apex, longer than parameres. Parameres robust in basal 2/3, subparallel-sided; apical arm thumb-like and slender, about 1/3 as long as paramere length, extended to apex of elliptic expansion of median lobe; dorsal inner margin with a strong incurved lobe just beyond apical arm, correspondent to the narrower position of apical 1/2 of median lobe and clamping median lobe; incurved lobe with apex round and sclerotized. Basal piece Yshaped, skewed and curled at apex, slightly shorter than parameres.

FEMALE (Figs. 6, 8,11), BL 17.0 mm; BW 5.0 mm. Larviform; body (Fig. 6) elongate, without elytral rudiments. Coloration milky white; thoracic notal and sternal discs, lateral margins of abdominal terga and pleurites pink which fade in alcoholic specimens; eye black, small; epicranium, antennae, labrum, mouthparts black, except M4 and apex of L3, and legs yellowish brown. Vertex weakly concave. Antenna (Fig. 11) pectinate but with branches not very long and with antennomeres condensed so that they seems serrate, a little longer than pronotum, 11-segmented; antennal sockets rounded, widely separated from each other. Clypeus+labrum fused with frons, trapezoidal. Pronotum semi-elliptical (PW/PL=1.1), with apical and lateral margins moderately elevated; no aerolet; longitudinal visible. Mesonotum transverse with center of apical edge concave, wider than pronotum (MsW / PW = 1.13). Metanotum sub-trapezoidal; a little wider than mesonotum (MtW/MsW = 1.11). Legs robust. Abdomen gradually smaller from basal to apical segments; apicolateral angles of terga dull at apices. Pair of two-spot photogenic organs on each of sternites+plurites 5– 6 (Fig. 8). Spiracles on pleurites.

Etymology. The specific name pectinealis refers to the pectinate antennae of the species.

Types. Holotype: male ( Fig. 1 ), near Nankang Nature Reserve Station of Gaoligong Mountains, N24.13810° / E098.12793°, 2186m, Nujiang Township, Baoshan City, Yunnan Province, China; labeled KIZ_F237, October 26–30, 2003, Collected by Xueyan Li. Allotype (Fig. 6) female, with the same collecting data as holotype. Paratypes: 10 males, with the same collecting data as holotype; one male (IOZ specimen), Son Tay County, Viet Nam, November, 1964, collected by Weiyi Wu. Holotype, allotype and most paratypes are deposited in Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming; other paratypes are deposited in Institute of Zoology, the Chinese Academy of Sciences, Beijing.

Additional specimens examined. Twenty-one males ( Fig. 2 ), near Nankang Nature Reserve Station of Gaoligong Mountains, N24.13810° / E098.12793°, 2186m, Nujiang Township, Baoshan City, Yunnan Province, China, October 29–30, 2006, Collected by Xueyan Li, Qingbai Hou, Meng Xie; Fourty-four males, Yangjie Township (Wubulu reservoir, altitude 1950 m) and Yinyuan Township (altitude 2010 m), Yuanjiang County, Yunnan, November 5–6, 2006, collected by Hong Hui.

Distribution. China: Gaoligong Mountains and Yuanjiang, Yunnan Province; Viet Nam: Son Tay County.

Ecological remarks (Figs. 3, 9). Males were found along roadsides in primary forest (Fig. 9) during winter. Males were usually active from 20:00–21:30 hrs and then gradually ceased activity. When active, they leave the forest and fly along the road. Males produce a continuous green glow during flight or sometimes at rest (Fig. 3). The glow is brighter than that of the sympatric species D. nubilus Jeng & Lai. One female was found on earthen walls along the roadside and it strongly glowed with a green light.

Discussion (Figs. 4–5). Diaphanes pectinealis is very similar in general characteristics to the sympatric species D. nubilus Jeng & Lai (Fig. 4) and to D. lampyroides (Olivier) from Xishuangbanna of south Yunnan (Fig. 5). Among these three species, distinct differences are mainly in antennae and male genitalia. Diaphanes pectinealis possesses pectinate antennae (Fig. 10) and male genitalia (Fig. 16) with a developed and sclerotized incurved lobe along the dorsal inner margin of parameres. Diaphanes lampyroides , transferred from Pyrocoelia by Lai et al. (1998), possesses serrate antennae and male genitalia with a less developed and less sclerotized incurved lobe along the dorsal margin of parameres than those of D. pectinealis . Diaphanes nubilus , with filiform antennae, agrees completely with all former Diaphanes definitions, including those of Motschulsky (1852), Gorham (1880), Olivier (1907a), McCermot (1964) and Jeng et al. (2001). Jeng et al. (2001) pointed out that D. nubilus from Taiwan is similar to D. luniger , the type species of Diaphanes . Even so, at first it was not certain if D. pectinealis should be placed into the same genus as D. nubilus , because of the different antenna from that of known species of the genus and it resembles species of Pyrocoelia such as P. r u f a in length of the 2nd antennomere and antennae.

FIGURE 3. (Figs. 10–16): 10. Male antenna; 11. Female antenna; 12. Male maxillary palpus; 13. Male labial palpi; 14. Male middle leg; 15. Male aedeagal sheath; 16. Male genitalia (16a. dorsal; 16b. ventral; 16c. lateral view). (scale lines = 1mm in Figs.10,11; scale lines = 0.5 mm in Figs. 12, 13, 14, 15, 16)

Analysis of molecular data ( Li et al. 2006) from the mitochondrial 16S rRNA gene from D. pectinealis , D. nubilus and D. lampyroides and characteristic Pyrocoelia species, including nine Japanese species and subspecies (P. r u f a Olivier, P. m i y a k o Nakane, P. atripennis Lewis , P. discidollis (Kiewenwetter) , P. f u m o s a Gorham, P. oshimana Nakane , P. matsumurai Nakane, P. m. kumejimensis Chûjô et Satô, P. abdominalis Nakane ) ( Suzuki, 1997), one Korean species (P. r u f a Olivier) ( Kim et al., 2000) and five Chinese species ( P. thibetana Olivier , P. amplissima Olivier , P. praetexta Olivier , P. motschulskyi (Motschulsky) , P. pygidialis Pic ), shows that D. pectinealis clusters with D. nubilus very well and then is joined by D. lampyroides . These molecular data imply that specimens with pectinate antennae are congeneric with Diaphanes with filiform, serrate or moniliform antennae, such as D. nubilus and D. lampyroides .

Regarding characteristics of the larviform female, it is again the antennal structure that distinctly differs D. pectineali s from D. nubilus and D. lampyroides . The female of D. pectinealis has pectinate antennae (Fig. 10) just like those of its male individuals, although the branches of each segment are much shorter than those on the males. According to Jeng et al. (2003) and our study of females specimens of these three species, the females of D. lampyroides possesses moderately serrate and very compact and thick antennae, while the antennae of D. nubilus females have typical filiform antennae.

The discovery of Diaphanes pectinealis and its combination of characters of both Diaphanes and Pyrocoelia , show that the traditional generic diagnoses and the limits between these two genera are greatly challenged. Further study may suggest a possible congeneric assessment of these genera.

Figures

FIGURE 1. (Figs. 1 – 8): 1. Habitus of holotype of Diaphanes pectinealis Li & Liang, new species, dorsal view; 2. live specimen of male of D. pectinealis; 3. Male of D. pectinealis glowing at rest; Fig. 4. Diaphanes nubilus from Nangkang, Gaoligong Mountains; Fig. 5. Diaphanes lampyroides from Xishuangbanna of South Yunnan; 6. Habitus of allotype of D. pectinealis, dorsal view; 7. Male abdomen and photic organs on each of ventrites 5 – 6; 8. Female abdomen and its photic organs on ventrites + plurites 5 – 6. (Scale lines = 10 mm in fig. 1 and 6; scale lines = 1 mm in Figs. 7, 8)

FIGURE 2. (Fig. 9): 9. The habitat of Diaphanes pectinealis in Nangkang, Gaoligong Mountains.