Costalampys gen. nov. Silveira, Roza, Vaz & Mermudes Figs 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22

Type species.

Costalampys delicata sp. nov., by original designation.

Etymology.

Costalampys is proposed in honor of our dear Professor and friend, the entomologist Dr. Cleide Costa, which greatly influenced our lives and the study of beetles. Gender feminine.

Diagnosis.

Antenna with 11 antennomeres, covered in decumbent, short and thin bristles (Fig. 11A-B, 12L), antennal socket wide, about half as wide as eye, close-set, reniform, antennifer process conspicuous (Fig. 12A-F). Maxillary palpomere IV fusiform (Fig. 12A-F). Labial palpomere III securiform, with sides divergent posteriorly (Fig. 12A-F). Pronotum roughly semilunar, with a marginal row of wider, deep punctures; disc convex in lateral view; hypomeron with ventral margin sinuose (Fig. 13A-D). Abdominal terga with posterior angles almost right-angled to slightly produced (Fig. 14A). Tibial spurs present. Male with antennomeres III-X cylindrical and basally flabellate, lamellae up to five times longer than antennomere, sternum IX exposed, apically rounded (Fig. 14C). Phallus with dorsal and ventral plates; dorsal plate basally fused to parameres, with a subapical transversal keel, without transverse groove, apically rounded or acute, not indented (Fig. 16I-L). Female with antennae compressed and serrate (Fig. 15C).

Description. Head Figs 11A, B, 12A-F);

Head capsule about a 1/3 × longer than wide (in dorsal view, Fig. 12A), lateral margins slightly convergent posteriorly (Fig. 12A), slightly longer than tall (in lateral view, Fig. 12 C). Frons slightly prominent and swollen (Fig. 12C). Antennal sockets reniform, 1/2 as wide as eye; antennifer process conspicuous (Fig. 12A-D). Vertex somewhat convex, posterior margin bisinuose (Fig. 12A, B). Antenna with 11 antennomeres, scape constricted proximally, pedicel almost as long as wide and constricted medially, antennomeres III-X subequal in length, with decumbent bristles; Frontoclypeus slightly curved anteriorly (Fig. 12C). Labrum connected to frontoclypeus by membrane; about 3 × wider than long, anterior margin straight to somewhat rounded, sclerotized or evanescent (Fig. 12D). Mandibles long and slender, monotonically arcuate, apex acute, internal tooth absent, external margin very sparsely setose at basal 1/2, bristles very thin and bright, barely visible (Fig. 12A-D). Maxilla with cardo well-sclerotized, triangular; stipe oblong in ventral view, internal margin slightly curved, posterior margins truncate, palp with four palpomeres; palpomere III triangular (dorsal view); IV lanceolate, with internal margin covered with minute, dense bristles, 2-3 × longer than III (Fig. 12A-D). Labium with mentum well-sclerotized and bristled, completely divided sagittally, forming two plates, each plate elliptic, with inner margin almost straight, outer margin rounded; submentum sclerotized and bristled, subcordiform, elongate; palp with three palpomeres, palpomere III securiform, sides divergent, apical margin slightly curved (Fig. 12A-D). Gular sutures conspicuous; gular bar transverse and strongly emarginate posteriorly, as wide as submentum greater width. Occiput pyriform, about a 1/3 × as wide as head posterior width (Fig. 12F). Tentorium long and slender, just slightly curved backwards, projected internally at basal 1/3, projection internally rounded (Fig. 12I-K). Thorax (Fig. 13A-L). Pronotum semilunar, posterior angles somewhat acute; disc slightly wider than long in dorsal view, convex, regularly punctured, punctures small and bristled; with a line of distinct deep marginal punctures; pronotal expansions well developed, anterior expansion maximal length almost half as long as disc, posterior expansion slightly sinuose, especially where disc meets lateral expansion, and by median line; slightly wider than humeral distance (Fig. 13A-D); lateral expansions straight in posterior view (Fig. 13C-D). Hypomeron slightly over 2 × longer than tall (Fig. 13C). Prosternum about 4 × as wide as its major length (Fig. 13B). Proendosternite apically clavate, as long as core prosternum major length (Fig. 12B, D). Mesoscutellum with posterior margin rounded (Fig. 13E). Elytra ellipsoid, 3-4 × longer than wide, pubescent, secondary pubescence present, with a line of conspicuous punctures all over sutural and lateral margins (Fig. 11 A, B). Hind wing well-developed, posterior margin sinuose, slightly over 2 × wider than long, r3 almost as long as r4, radial cell 2.5 × wider than long, almost reaching anterior margin, costal row of setae inconspicuous (Fig. 13L); CuA2 crossvein absent, mp-cu crossvein present; RP+MP1+2 as long as 3/4 × r4 length, reaching distal margin, J indistinct (Fig. 13L). Alinotum slightly wider than long, lateral margins slightly convergent posteriorly, posterior margin slightly curved; prescutum extending slightly beyond than half metascutum length (Fig. 13E); rounded area of scutum weakly sclerotized, scutum-prescutal plates sclerotized and extending ridges to alinotum posterior margin; metascutellum glabrous. Mesosternum weakly sclerotized, posterior margin medially acute (Fig. 13F, G). Mesoepimeron connate to metasternum (Fig. 13G). Mesosternum-mesepisternum suture barely visible (Fig. 13G). Mesepisternum-mesepimeron suture conspicuous (Fig. 13F, G). Metasternum strongly depressed by mesocoxae, anterior medial keel prominent up to anterior one third, discrimen reaching basal 1/2 of metasternum length, lateral margins divergent posteriorly up to lateral-most part of metacoxa, then convergent posteriorly, posterior margin bisinuose (Fig. 13F, G). Profemur about as long as protibia, meso and metafemora slightly shorter than respective tibiae (Fig. 13I-K). Tibial spurs present (Fig. 13I-K). Tarsomere I about 2 × longer than II, II 2 × longer than III, III subequal in length to core IV, IV bilobed, lobes reaching two thirds V length, V with claws simple, without inner teeth (Fig. 13I-K). Mesendosternum with two parasagittal projections directed outwards, irregularly alate (Fig. 13I-K). Metendosternum spatulate, roughly rhomboid, diamond-shaped (2 × longer than wide, median projection acute anteriorly and posteriorly, with two acute lateral laminae) (Fig. 13H). Abdomen (Fig. 14A-H). Tergum I with anterior margin membranous (Fig. 14A), laterotergite membranous, roughly rectangular, with sparse bristles (Fig. 14A); spiracle elliptical, obliquely attached to thorax, more vertically so (Fig. 14A). Terga II-VII with posterior corners almost right-angled to slightly projected, somewhat rounded, posterior margins somewhat rounded (Fig. 14A, B). Sterna II-IX visible (Fig. 14B), VI often bearing a rounded lantern, of variable size. Spiracles dorsal, at sternum anterior th (Fig. 14A, B). Sternum VIII with lateral “larval” lanterns, posterior margins medially sinuose or mucronate (Fig. 14A, B). Pygidium with posterior margin centrally rounded (Fig. 9H) or almost truncate (Fig. 17H), sometimes posteriorly mucronate (Fig. 14C) posterior corners weekly produced or barely present. Male. Antennomeres III-X cylindrical and flabellate, with lamellae long and slender, of variable length, apical antennomere at least slightly longer than subapical one (Fig. 12L). Syntergite consisting of paired lateral plates convergent posteriorly (putatively tergite IX or paraproct), median transversal suture absent, anterior margin mildly to strongly convergent (Fig. 14D, E); not posteriorly fused to sternum IX. Sternum IX roughly symmetric, posterior margin rounded. Phallus (Fig. 14F-H) with a dorsal and a ventral plate; dorsal plate basally fused to parameres, without a transverse groove apically rounded or acute, not indented), curved dorsally or straight (in lateral view), with a subapical transversal keel; ventral plate elongate, with sides straight. Paramere slightly longer than dorsal plate, with a ventral subapical tooth. Female (Fig. 15D-I). Antenna compressed and serrate, with apical corners almost right-angled or projected and acute (Fig. 15A-C). Sternum VIII as long as wide, spiculum ventrale long and slender, 3/4 × as long as sternum (Fig. 15D, E). Internal genitalia with a slightly sclerotized, elongate spermatophore-digesting gland, almost twice as long and slightly wider than the spermatheca, which is membranous and globose (Fig. 15F-I). Ovipositor short, valvifers free and slightly curved, slightly over 2 × longer than coxite; proximal plates sclerotized, fused medially in a somewhat C-shaped structure (with sides straight and convergent apically, medially straight anteriorly, posterior margin slightly curved), coxites apically free (i.e. not fused), coxital baculi well-developed, sclerotized, apically convergent; styli as long as 1/4 × coxite length, well-sclerotized; proctiger well-developed, formed by two elongate plates, convergent apically, laterotergite rudimentary, subquadrate in ventral view, weakly sclerotized, barely attached to valvifers (Fig. 15 F,G).

Biology.

Five species of Costalampys gen. nov. have been observed active during daytime, namely C. decorata (Olivier, 1888) comb. nov., C. delicata sp. nov., C. joanae sp. nov., C. pauper (Olivier, 1899) comb. nov., and C. tricolor (Gorham, 1880) comb. nov. Males and females were observed perching on leaves of understory bushes and growing trees (as in Fig. 10). Males will sustain the antennae erect and pointed out towards the wind current, very similar to other firefly taxa with flabellate antennae, like many Ethra Laporte, 1833, Amydetes Illiger, 1807 and Cladodes species (L. Silveira pers. ob.). Given the similarity in overall morphology, it is likely that other Costalampys gen. nov. species in the genus are also diurnal. Where observed, lanterns are functional, and individuals will glow if disturbed. Other roles of bioluminescence (e.g., in courtship) are unknown.

Distribution.

In the Atlantic rainforest, with occasional records in adjacent Caatinga patches.

Remarks.

Costalampys gen. nov. superficially resembles the neotropical genera Psilocladus (type genus of Psilocladinae), Amydetes (type genus of Amydetinae), and Ethra ( Lampyrinae) due to the branched antennae. Costalampys gen. nov. was found closer to lampyrine taxa in all our analyses, and never clustered with Amydetes ( Amydetinae) or Psilocladus ( Psilocladinae). Therefore, Costalampys gen. nov. is here tentatively placed as Lampyrinae, notwithstanding the lack of definitive diagnostic characters for the Lampyrinae (cf. Jeng 2008, Martin et al. 2019). While the tribal classification within Lampyrinae remains unsteady (Martin et al. 2019), we place Costalampys gen. nov. as incertae sedis within the subfamily.

Males of Costalampys gen. nov. especially resemble those of Ethra ( Lampyrinae), and specimens we now recognise as Costalampys were often found in collections identified as Ethra (L. Silveira, unpublished results). However, Costalampys gen. nov. can be distinguished from Ethra by: antennal lamellae (Fig. 12L) basally inserted (apically inserted in Ethra); labial palpi (Fig. 12A-F) with sides apically divergent (parallel-sided in Ethra); and pygidium with sides rounded (Fig. 14C) (straight in Ethra). Females of all Ethra spp. remain unknown.

Costalampys gen. nov. shares several similarities with Scissicauda McDermott 1964, such as: antennal sockets large and close-set; maxillary palp with palpomere IV large and fusiform, submentum cordiform, pronotum semilunar, proendosternite apically clavate, elytral outline ellipsoid; metaendostenrite elongate, rhomboid; abdominal sternum II bearing paired vitreous spots medially; aedeagus with phallus bearing dorsal and ventral plates, dorsal plate enlarged apically, projecting ventrally and partially embracing the internal sac. It is also noteworthy that the genotypic S. disjuncta also has basally flabellate antennae, although its bristles are long and erect (Silveira et al. 2016b). However, Costalampys differs from Scissicauda by: pronotal disc strongly convex in lateral view (almost flat in Scissicauda); hypomeron strongly sinuose (mildly sinuose in Scissicauda); sternum VIII as long as VII, posterior margin medially mucronate or slightly sinuose (at least a 1/5 × longer, and posterior margin strongly sinuose in Scissicauda); sternum IX visible (concealed in Scissicauda); male pygidium rounded posteriorly, sometimes mucronate (with sides divergent and posterior margin strongly indented in Scissicauda); phallus with dorsal plate without a transverse medial groove (present in in Scissicauda); internal female genitalia with spermatheca (absent in Scissicauda [based on the type species S. disjuncta]), ovipositor in Scissicauda [based on the type species S. disjuncta]).