Curtos Motschulsky

Fu, Xinhua, Ballantyne, Lesley & Lambkin, Christine, 2012, Emeia gen. nov., a new genus of Luciolinae fireflies from China (Coleoptera: Lampyridae) with an unusual trilobite-like larva, and a redescription of the genus Curtos Motschulsky, Zootaxa 3403, pp. 1-53 : 17-23

Curtos Motschulsky

Curtos Motschulsky, 1845:36 ; 1853:51. Lacordaire, 1857:337. Olivier, 1907:55; 1910:47. McDermott, 1964:47; 1966:118. Chûjô & Satô 1970:59. Jeng et al. 1998:331.

Type species. Curtos mongolicus Motschulsky by original designation.

Diagnosis. Males distinguished from all other Luciolinae by the elytral punctation, which is wide and regularly spaced, and a pronounced longitudinal humeral carina; one of a group of Luciolinae in which the aedeagal lateral lobes are visible from beneath at the sides of the median lobe, differing from other Luciolinae in that the lateral lobes are of uneven length. Females macropterous with the same elytral characteristics as the male. Larva pale, terrestrial and soft bodied, with no plates heavily sclerotised nor darkened, and laterotergites visible at the sides of the body.

Redescription. This redescription is based on the two species Curtos costipennis (Gorham) and C. okinawanus Matsumura , scored in this analysis.

Male ( Figs 32, 33 ). Pronotum dorsal surface without irregularities in posterolateral areas and longitudinal groove in lateral areas; punctation dense. Anterior margin not explanate. Pronotum usually subparallel-sided, with margins straight (B=C); if not subparallel-sided then with B>A and C or C> A and B often in the one species; pronotal width subequal to humeral width; anterolateral corners rounded obtuse; lateral margins without indentation at mid-point, or sinuousity in either horizontal or vertical plane; without indentation in lateral margin near posterolateral corner, and irregularities at corner; posterolateral corners rounded, obtuse, or angulate, and subequal to 90°; posterolateral corners not projecting as far as median posterior margin and separated from it by defined emarginations.

Hypomera closed. Median area of hypomeron not elevated in vertical direction; posterior area of hypomeron flattened and closely adpressed; pronotal width/ GHW index 1.2 or less.

Elytron punctation dense, not linear, as large as that of pronotum, and regular in size and distribution; apices not deflexed; epipleuron and suture extend beyond mid-point, almost to apex but not as ridge around apex, neither thickened in apical half; no interstitial lines; elytral carina present; in horizontal specimen viewed from below epipleuron at elytral base wide, covering humerus; viewed from above the anterior margin of the 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; lateral margins sub-parallel-sided.

Head moderately depressed between eyes; moderately 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; antennal sockets on head between eyes, not contiguous, separated by <ASW or up to 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 non-lunate, laterally compressed, of form of a narrow triangle (widest at base and length 2– 3 X width), with inner edge entire, and at least half as long as apical maxillary palpomere. Antennae 11 segmented; length> GHW up to 2 X GHW; no segments flattened, shortened, or expanded; pedicel not produced; FS1 not shorter than pedicel.

Legs with inner tarsal claw not split; without MFC; no femora or tibiae swollen or curved; no basitarsi expanded or excavated.

Abdomen ( Fig. 33 ) without cuticular remnants in association with aedeagal sheath; no ventrites with curved posterior margins nor extending anteriorly into emarginated posterior margin of anterior segment; LO in V7 entire usually occupying half or less of V7, and often not reaching to sides or posterior margin or into MPP (see Jeng et al. 1998 Figs 22–31 ); (reaching posterior margin in some examples of okinawanus and costipennis scored here); posterior half of V7 not arched or swollen, muscle impressions not visible in this area; neither anterior nor posterior margin of LO emarginate; LO present in V6, occupying almost all V6. MPP present, symmetrical, apex rounded, not laterally compressed, about as long as wide (L=W), not inclined dorsally nor engulfed by T8 apex, without dorsal ridge, median longitudinal trough. V7 without median carina, median longitudinal trough, anteromedian depression on face of LO, incurving lobes or pointed projections, median ‘dimple’, or reflexed lobes; posterior margin of V7 without PLP and posterolateral corners rounded. T7 without prolonged anterolateral corners. T8 symmetrical, width=length (some of the species depicted by Jeng et al. 1998 Figs 22–31 have T8 wider than long), visible posterior area not narrowing abruptly, median posterior margin not emarginated in specimens of costipennis and okinawanus scored here ( Jeng et al. 1998 Figs 22–31 depict the posterior margin of T8 medially emarginated); widest across middle with lateral margins slightly convex-sided; without prolonged posterolateral corners, median posterior projections, not extending conspicuously beyond posterior margin of V7; posterior margin not inclined ventrally not engulfing posterior margin of V7 nor MPP; T8 ventral surface without median longitudinal trough; without lateral depressed troughs, asymmetrical projections, median posterior ridge; concealed anterolateral arms of T8 short and narrow, not laterally emarginated before their origins, not expanded dorsoventrally; without bifurcation of inner margin and ventrally directed pieces; lateral margins of T8 not enfolding sides of V7.

Aedeagal sheath approx. 3 times as long as wide; without bulbous paraprocts; similar in outline to aedeagal sheath of Atyphella Olliff species with sheath sternite emarginate on its right side from point of articulation with tergite; anterior half of sternite broad, apically rounded; tergite without lateral arms extending anteriorly at sides of sheath sternite; tergite with small projecting pieces along posterior margin of tergite 9, anterior margin without transverse band.

Aedeagus length/width 2.5–3/1; LL lack lateral appendages; LL visible from beneath at sides of ML, LL/ML moderate to wide; LL of unequal length, slightly shorter than ML, separated longitudinally by most of their length; LL apices rounded and inturned when viewed from the side; dorsal base of LL symmetrical, not excavated; LL without lateral hairy appendages along their outer ventral margins, not produced preapically nor narrowly on inner apical margin; without projection on left LL; inner margins without slender leaf-like projection; ML symmetrical, 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, in two distinct pieces while not strongly emarginated along anterior margin.

Female ( Figs 34, 35 ). Macropterous and assumed capable of flight. Similar in colour and dorsal facies to male. Elytral punctation as large as that of pronotum, evenly spaced; no interstitial lines; elytral carina present. No legs or parts thereof swollen and /or curved. LO in V6 entire, without any elevations or depressions or ridges on V7; median posterior margin of V7 shallowly emarginate; median posterior margin of V8 broadly and shallowly. No obvious bursa plates.

Larva ( Figs 36–42 ). Terrestrial, pale soft bodied; with 3 thoracic and 10 abdominal terga; lateral margins of thoracic and abdominal terga not explanate and flattened; lateral margins of abdominal tergum 10 parallel-sided; arrangement of ventral surface conforming to that described for Pteroptyx valida Olivier (Ballantyne & Rasainthiran Menayah 2002) : an elongate pleural suture runs from anterior margin of mesothorax to posterior margin of abdominal segment 9, delimiting laterotergites bearing spiracles above and laterosternites and a single median sterna element below; the median thoracic sternal elements are divided into two, each margined by laterotergites (only the mesothoracic laterotergites bearing spiracles). Head and antennae of typical Luciolinae form as described in Ballantyne and Rasainthiran Menayah (2002); mandibles lacking inner tooth; antennae with short slender terminal segment surmounted by hairs; sense cone shorter than AS 3; maxillary and labial apical palpomeres elongated pointed with terminal sense organs. Legs: without brush of hairs from apex of tibiotarsus.

Discussion. The genus Curtos was established by Motschulsky (1845) for a single species C. mongolicus which he designated as the type. It appears that no subsequent revision of the genus actually included an examination of the type (Jeng pers. com.) and here we address Curtos sensu Chûjô & Satô (1970) and Jeng et al. (1998).

Motschulsky’s (1845) description, in citing but not elaborating on differences between Curtos (Lampyridae) and Drilus (a non firefly genus of the family Drilidae ) was inadequate, as were supplementary descriptions of both the genus and type species ( Motschulsky 1852, 1854). Curtos was redefined by Chûjô & Satô (1970) who highlighted several features they considered distinctive including the strong elytral punctation and the presence of a ‘post-humeral costa’ (the elytral carina). Ballantyne and Lambkin (2009) found these two characters useful in helping to define the genus. Chûjô & Satô’s key (1970 page 60) distinguished Curtos from Luciola . While Ballantyne and Lambkin (2009) have begun the process of subdividing the genus Luciola and defining Luciola s. str., it has not been possible to determine what species of Luciola Chûjô and Satô used in their key. Of the five characters they used, the usefulness of two, the shape and dentition of the apical labial palpomere and the semicircular shape of the pronotum is hereby challenged. The dentition of the apical labial palpomere is very variable in the Luciolinae (see Table 3 ) with the type species Luciola italica (L.) having a broad triangular apical palpomere with the inner margin dentate.

Of the Luciolinae examined by Ballantyne and Lambkin (2009) over ten genera have a pronotum that could be described as semicircular in outline from above (see Ballantyne & Lambkin 2009 Figs 4, 5 , 12, 15 , 17, 19, 21, 23, 25 , 34 , 40 , 63, 64, 65, 67, 68–74, 76, 77, 78, 118, 122–129, 137, 147, 150, 151, 158, 159, 166, 169, 177, 187, 196, 207–210, 229, 230, 255–263, 284, 285, 317, 318, 330–335, 337–340, 379, 382, 397, 407, 417, 418, 446, 447, 462, 469, 480, 490, 499, 504). The two species examined here, as well as most of the species pictured by Jeng et al. (1998) have a pronotum where the sides are best described as subparallel.

Jeng et al. (1998) revised Curtos species from Taiwan and while not giving a generic redescription they mentioned the usefulness of the non toothed apex of the apical maxillary (not labial) palpomere (error confirmed by Jeng pers. com.), and the humeral carina, as taxonomic characters. All the species they figured had distinctive elytral punctation, a well defined humeral carina and lateral lobes of the aedeagus of uneven lengths, all features used in defining Curtos in keys to genera in Ballantyne and Lambkin (2009) and herein.

Geisthardt (2004) considered Curtos well defined in the Luciolinae by the presence of the “impressions at the base of the posterior angles” in the pronotum. This feature was not used in the male characters analysed by Ballantyne and Lambkin (2009), nor herein, as such depressions are common to almost all species of Luciolinae examined thus far (see Ballantyne & Lambkin 2009 previously quoted figures of dorsal pronota). Jeng et al. (1998) indicated the females of Curtos are macropterous, and the larvae milky white, living in moist soil and preying on small snails. Chen (2003) illustrated the larvae, and Ballantyne and Lambkin’s phylogenetic analysis (2009) included the scoring of the morphological characters for one species of Curtos larva.

Curtos is presently known from 19 species from SE Asia especially China including Taiwan ( Table 4 ). No recent revision addresses all these species and there is as yet no key to all the species of Curtos .

Figures

FIGURES 32 – 36. Habitus Curtos costipennis. 32, 33 male, 34, 35 female, 36 larva. (32, 34, 36 dorsal, 33, 35 ventral) (Scale bar = 5 mm).

FIGURES 16 – 25. Emeia pseudosauteri male 16 – 22, female 23 – 25. 16, 17 aedeagal sheath (right margin of posterior section of sheath sternite arrowed in 16). 18, 19 aedeagus. 20 – 21 entire abdomen. 22 T 8. 23 genitalia, anterior end to top of page. 24, 25 female after prolonged soaking in ethanol, illuminated from below (extent of hind wing arrowed in 24). (16, 18, 20 22, 24 ventral, 17, 19, 21, 25 dorsal). (Scale bar = 1 mm).

FIGURES 26 – 30. Emeia pseudosauteri fifth instar larva SEMs. 26, 27 head. 28 maxillary palp. 29 apex apical maxillary palpomere. 30 body. (27, 28 ventral, 26, 30 dorsal).

FIGURES 1 – 6. Habitus Emeia pseudosauteri. 1, 2 male; 3, 4 female; 5, 6 larva (1, 3, 5 dorsal; 2, 4, 6 ventral) (Scale bar = 5 mm).

FIGURES 10 – 15. Characters and states. Adult males. 10 – 12 Luciola indica Motschulsky male. 13 – 15 undescribed species 7 (Figure 7 number 4) male. 10, 11 whole body, (character 119); 12 aedeagus (character 271); 13, 14 terminal abdomen; 15 T 8 (10, 13, 15 ventral, 11, 12, 14 dorsal (characters 121 – 123).

FIGURES 37 – 42. Curtos costipennis larval head SEMs. 37 anterior; 38, 39 entire head; 40 detail anterior margin; 41 outer margin tip of mandible; 42 left antenna (37 dorsal surface uppermost; 38 dorsal; 39, 40 42 ventral).