Phaenostoma tupiniquim, Clarkson, Bruno & Takiya, Daniela Maeda, 2017

Clarkson, Bruno & Takiya, Daniela Maeda, 2017, A new species of Phaenostoma d’Orchymont, 1937 (Coleoptera: Hydrophilidae) from Brazil, Zootaxa 4236 (2), pp. 375-380 : 376-379

Phaenostoma tupiniquim sp. nov.

(Figs. 1 to 8)

Diagnosis. Large-sized species (4.0– 4.4 mm in length). Eyes separated by 5× the width of one eye in dorsal view (Fig. 1). Clypeus slightly arcuate in dorsal view. Elytral punctuation finer on disc and gradually becoming coarser laterally and posteriorly; with most trichobothria situated within large punctures (Fig. 1, Fig. 4, and Fig. 5). Mesometaventral keel narrow; anterior hood of preepisternal plate wide, distinctly bordered, on the same plane as the rest of the keel in lateral view (Fig. 2 and Fig. 3). Aedeagus (Fig. 7 and Fig. 8) manubrium very short; parameres wide, convex on outer margin, apex turned inwardly, acuminate; median lobe thick, margins slightly convex, gradually narrowing apically, blunt at apex, with corona subtriangular.

Description. Holotype male.

Size and form. Total length 4.10 mm; maximum width 2.53 mm; maximum width of the head 1.23 mm; elytral length 2.55 mm; maximum width of the pronotum 2.40 mm; maximum height 1.35 mm. Body broadly oval, moderately convex (Fig. 1).

Color. Dorsum of head, pronotum, and elytra dark brown to black: head dark brown, with the front darker (Fig. 1); pronotum dark brown, disc darker. Elytra disc black, with lateral and posterior margins dark-brown. Antennae and maxillary palpi uniformly pale brown; labial palpi brown (Fig. 2). Ventral face almost totally dark brown; ventral face of head and prothorax reddish brown; femora dark-brown; tibiae reddish brown, tarsus pale brown (Fig. 2).

Head. Labrum weakly sclerotized, not totally concealed by clypeus. Clypeus and frons finely and sparsely punctate; punctures about a third of the width of one ommatidium, distance between punctures three to four times the width of one puncture; interstices of clypeal disc without microsculpture. Trichobothria on clypeus and frons consisting of several scattered punctures of about same diameter as surrounding punctures, discrete, distinguishable only by bearing very short, fine setae. Frontoclypeal suture weakly marked. Eyes separated by five times the width of one eye in dorsal view. Maxillary palpomere 1 minute; palpomere 2 longer than palpomeres 3 and 4; palpomere 3 slightly shorter than palpomere 4; palpomeres 2 and 3 slightly curved inwards and widened distally; palpomere 4 narrowest. Labial palpi about half of the width of mentum. Mentum bare, with some scattered short setae, smooth, somewhat depressed on anterior half, with anterior margin sinuate (Fig. 2).

Thorax. Pronotum convex, with a bead on anterior and lateral margins; anterior corners rounded, posterior corners weakly angulate; posterior margin continuous. Pronotal punctation evenly distributed, very fine and sparse; distance between punctures three to five times the width of one puncture. Trichobothria on pronotum consisting of several scattered punctures similar to those on head. Elytral punctation coarse (but weakly impressed), sparser on elytral disc, distance between punctures ca. two to three times the diameter of one puncture (Fig. 1); gradually becoming coarser and denser on lateral and posterior portions, distance between punctures ca. half to twice the diameter of one puncture; most trichobothria set within larger punctures on lateral and posterior portions (Fig. 5). Sutural stria strongly marked on posterior third (Fig. 1 and Fig. 4). Elytral margins beaded laterally and posteriorly, weakly explanate on lateral margin. Prosternum flat, anterior margin slightly elevated medially, without carina. Mesoventrite highly elevated medially into preepisternal plate, widely attaching and as high as anterior portion of metaventral process, forming a meso-metaventral keel (Fig. 3); preepisternal plate narrow, laterally subparallel, with anterior hood wide, distinctly bordered, on the same plane as the rest of the process in lateral view; hood anteriorly blunt in ventral view. Metaventral process narrow, as wide as preepisternal plate near meso-metaventral suture, widening posteriorly until half-length of mesocoxae, evenly wide posteriorly until margin; bare at middle portion; with sparse setae laterally (Fig. 3). Lateral portions of metaventrite sparsely pubescent (Fig. 2). Procoxae pubescent; profemur pubescent on basal two-thirds; ventral surface of meso- and metafemur bare, reticulate, with scattered setiferous punctures (Fig. 2).

Abdomen. Surface of abdominal ventrites with mesh-like microsculpture; sparsely pubescent (Fig. 2). Sternite IX wide basally; bearing rather narrow tongue-shaped median projection; lateral struts arcuate; slightly shorter than median projection (Fig. 6). Aedeagus (Fig. 7 and Fig. 8) 0.80 mm long. Phallobase symmetrical; short, ca. 0.20 times the aedeagal length; widest than long, maximum width on apical portion; manubrium distinct, narrow, rounded at base; about a third of phallobase length. Parameres longer than median lobe, outer margin convex; apex acuminate, turned inwardly; inner margin sinuate on dorsal view. Median lobe thick; outer margins slightly convex, gradually narrowing on apical third; apex blunt, almost reaching apex of parameres; corona distinct, subtriangular; wider than longer, subapical; basal apophyses within parameres, almost extended into phallobase, subparallel.

Etymology. The specific name “ tupiniquim ” refers to an indigenous tribe of the tupi nation. They were the first indigenous people to face the Portuguese fleet of Pedro Alvares Cabral on April 23rd 1500, upon their arrival in Northeastern Brazil. “ Tupiniquim ” (or “tupiniquins”) is often used as a synonym of Brazilian (Brazilians). The name stands as a noun in apposition.

PLATE 1. Figs. 1 to 8. Phaenostoma tupiniquim sp. nov., 1: dorsal habitus; 2: ventral habitus; 3: meso-metaventral keel in ventral view; 4: elytra in posterior view; 5: left elytron in lateral view, white arrows indicate the trichobothria, red arrows indicate trichobothria set within larger punctures; 6: sternite IX; 7: aedeagus in dorsal view; 8: aedeagus in ventral view.

Distribution. Brazil: Ceará, Mato Grosso (?), and Pará (?) states.

Differential diagnosis. The new species is one of the largest species of the genus described so far, with body length 4.0 mm or larger, together with P. urichi (4.1–4.6 mm), while the remaining species are smaller than 4.0 mm in length. However, both species are quite distinct regarding the remaining diagnostic characteristics. Similar to P. kontax , P. tupiniquim sp. nov. have finer punctuation on elytral disc which becomes coarser laterally and posteriorly, with most trichobothria situated within large punctures mainly on lateral and posterior portions. Nonetheless, P. kontax shows lateral and posterior punctures conspicuously shallower and coarser forming “recessed discs” as described by Gustafson & Short (2010). The dorsal sculpture is evenly coarse in P. stochasma and in P. urichi . Similar to P. stochasma , the new species have anterior hood of preepisternal plate at the same plane as the rest of the keel in lateral view (preepisternal plate of P. urichi does not have an anterior hood and the remaining species have hood located above the plane of the meso-metaventral keel). Nevertheless, both species are quite distinct regarding the remaining diagnostic characteristics.

In general, P. tupiniquim sp. nov. seems to be quite similar to the widespread species P. posticatum . However, the new species can be distinguished by the length of the manubrium (longer in P. posticatum ), shape of parameres (more convex laterally and more strongly turned inwardly in P. tupiniquim sp. nov., subparallel and sinuate apically in P. posticatum ), and shape of median lobe (with margins slightly convex and gradually narrowing in apical third in P. tupiniquim sp. nov. and slightly convex only at basal half and abruptly narrowing in apical half in P. posticatum ). The elytral sculpture (coarser on pronotal disc becoming finer laterally and posteriorly in P. posticatum ), together with the aspect of the hood near meso-metaventral keel (located above the plane of the mesometaventral keel in P. posticatum ), helps distinguish the new species.

Type material. Holotype (male): “ BRASIL: Ceará, Ubajara, Parque Nacional / de Ubajara, Ponte sobre Rio Miranda ,/ 15.II.2013, 03°50’07” S 40°54’48” W,/ 792m, pennsylvania light trap, Santos, A.P.M. & Takiya, D.M. col.” ( CZMA) ; Paratypes (2): BRAZIL: Mato Grosso (?): “ Chapada / Brazil / Acc. No. 2966// Chapada / Forest // July ” (1 female, SEMC) ; Pará (?): “ Taquara / Brazil / Acc. No. 2966// July ” (1 male, SEMC) .

Additional material examined. BRAZIL: Mato Grosso (?): “ Chapada / Brazil / Acc. No. 2966// Chapada / Forest // July ” (3 exs., CMNH) ; Pará (?): “ Taquara / Brazil / Acc. No. 2966// July ” (1 ex., CMNH). These four specimens were quickly examined by BC and, although they agree in external morphology with this distinctive species, we decided not to designate it as part of the type material since they were not properly dissected.

Remarks. Phaenostoma posticatum was described from Panama and subsequently recorded from Brazil and Peru ( Orchymont 1943a, b). Concerning the Brazilian records, Orchymont (1943a) mentioned three specimens of P. posticatum from Pernambuco and one from Alagoas, both states in the Northeastern Region, as is the typelocality of the new species. These records are old and the disjunct distribution between Central America and Northeastern Brazil is unusual for Coelostomatini - known only for P. posticatum and Phaenonotum globulosum (Mulsant, 1844) ( Orchymont 1943a) . The examination of specimens cited by Orchymont (1943a) is needed in order to confirm the identification of the species, especially because of the substantial increase of knowledge on the genus since these records were made.