Crenitulus clarksoni Pes 2017, sp. nov.
Creators: name: Pes, Ana Maria
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Hydrophilidae
Crenitulus
Crenitulus clarksoni

description: Crenitulus clarksoni sp. nov.
(Figs. 1 A–C, 2 A–F, 3)
Type locality. Brazil: Amazonas State, Manacapuru Municipality, flooded banks of a river, in backwaters (03°13'49.3''S 060°38'33.7''W).
Type material. Holotype male (INPA): Brazil: Amazonas State, Manacapuru Municipality, flooded banks of a river, in backwaters (03°13'49.3''S 060°38'33.7''W), 09.vi.2017, leg. C.J. Benetti & L. Santana. Condition of holotype: stored in 80% ethanol with the dissected male genitalia stored in microvials with glycerin (INPA). Paratypes (76): BRAZIL: Amazonas State: same data as holotype, [five males stored in 80% ethanol, and eight males and 15 females stored in 99% ethanol; 20 deposited at INPA, four deposited at SEMC, four deposited at MZUSP]. Roraima State: Boa Vista Municipality, pond near the RR-205 road (02°53'03.5''N 060°52'45.5''W), 13.viii.2015, leg. C.J. Benetti, K.D. Silva, L. Santana. [three males and five females stored in 80% ethanol, deposited at INPA]; Boa Vista county, pond near the RR 205 and "estrada do contorno" (02°49'20.0''N 060°48'43.9''W), 13/viii/2015 [16 males and one female stored in 80% ethanol, 13 deposited at INPA, four deposited at SEMC]; Alto Alegre county, pond near the RR-205 road (02°59'48.7''N 061°07'48.7''W), 05/vi/2015 [two males and three females stored in 80% ethanol, deposited at INPA]; GUYANA: Region IX: large shallow lagoon/marsh, near Kusad Mountains (02°52'12.24''N 059°55'00.18''W), 26.x.2013, leg. A. Short, Isaacs, Salisbury [18 specimens deposited at CBDG, INPA, SEMC].
Differential diagnosis. Crenitulus clarksoni sp. nov. can be distinguished from other species of Crenitulus by the following combination of characteristics: body size 1.6–1.8 mm in length; clypeus, frons, pronotum and elytra black, pronotum with distinctly demarcated yellow lateral margins, reaching the anterolateral angles and posterior margins and elytra with yellow margins on its posterior half (Fig. 1 A); presence of dorsal pubescence (Fig. 1 A); presence of longitudinal rows of coarser punctures on lateral margins of elytra (Fig. 1 B); apical antennomere 1.5 times longer than wide and 2.5 times longer than antennomere 8 (Fig. 2 A); maxillary palpi 2.5 times longer than wide and 2.2 times longer than palpomere 3 (Fig. 2 B); mesoventrite nearly flat; procoxae with strong, large spines; femoral pubescence confined to anterior margin and proximal portion (Fig. 2 E) and by the male genitalia shape (Fig. 2 F, 3), with phallobase as long as parameres, parameres narrowed apically with the apex rounded and median lobe slightly shorter than parameres with corona in subapical position.
Description. Habitus (Fig. 1). Shape oval, greatest width and maximum convexity near the elytral base; elytra about three times as long as pronotum.
Color. Head, pronotum and elytra black; pronotum with distinctly demarcated yellow lateral margins, reaching the anterolateral angles and posterior margins; elytra with yellow margins on its posterior half; ventrally black, legs dark-brown with distal portion light brown.
Measurements (n = 10). BL: 1.6–1.8 mm; BW: 0.9–1.0 mm; PL: 0.3–0.4 mm; PW: 0.8–0.9 mm; EL: 1.0– 1.2 mm.
Head. Labrum moderately narrow. Labrum, clypeus and frons entirely black. Irregular fine punctures, mixed with a few slightly coarser punctures, densely distributed, denser towards clypeal margins and on frons; diameters of punctures slightly smaller than interstices, with minute setae inserted in a few of the punctures; a series of very fine densely arranged punctures present along inner margins of eyes; interstices shiny without microsculpture; eyes not emarginated anteriorly, dorsal portion slightly oval shaped; clypeus moderately long in longitudinal diameter, slightly convex anteriorly, with blunt angles between lateral and anterior portion; frontoclypeal suture scarcely visible; antennae nine-segmented; pedicellus short and stout, antennomere 3 as long as or longer than antennomeres 4 and 5 together; apical club segment oval, up to 1.5 times as long as wide; maxillary palpi stout, palpomere 2 inflated; palpomeres 1–3 yellow, palpomere 4 black with terminal infuscation; mentum, gula, submentum, cardo, and stipes black; mentum 1.7 times as wide as long, posterior portion flat, anterior portion with protruding median region; setiferous punctures distributed mainly in the median and posterior region; labial palpi yellow, slender, palpomeres 2 and 3 of same length, together approximately as long as lateral margin of mentum.
Thorax. Pronotum black, with distinctly demarcated yellow lateral margins, reaching the anterolateral angles and posterior margins; irregular punctuation even finer than on head, densely distributed, punctures slightly coarser and denser towards lateral margins; very fine setae inserted in some of the lateral punctures; interstices smooth, shiny, without microsculpture; prosternum dark brown to black, flat, very slightly projecting towards gula mesally; lateral portion of hypomeron light brown, mesal portion dark brown; scutellar shield dark brown to black, smooth, feebly punctured; elytra black, with yellow margins in its posterior half; elytral punctures coarser than on pronotum, with subserial arrangement, finer on anterior portion, with longitudinal rows of coarser punctures on lateral margins; elytra distinctly pubescent, with a fine seta in each puncture; sharply impressed sutural stria present in posterior two thirds of elytra; mesoventrite dark brown to black, nearly flat; anapleural sutures S-shaped; epipleura, meso- and metaventrite dark brown to black.
Legs. Dark brown as ventrites; procoxae pubescent and with some large spine-like setae on mesal face near trochanteral join; mesofemur almost entirely pubescent except extreme apical portion; on metafemur pubescence confined to anterior margin and proximal portion; metatibia with moderately strong spines on lateral margin; Tarsi with setae on dorsal face of tarsomeres; metatarsus as long or slightly longer than metatibia.
Abdomen. Ventrites dark brown to black, entirely covered with dense hydrofuge pubescence.
Aedeagus. Phallobase as long as parameres; parameres narrowed apically, regularly convex on outer margin and almost straight on inner margin, apices rounded; median lobe slightly shorter than parameres, corona in subapical position, basal apophyses short, with very short extension into phallobase.
Etymology. This species is named in honor of Bruno Clarkson, a good friend and colleague, in recognition of his contribution to the knowledge of water scavenger beetles.
Distribution. Southwest Guyana and northern Brazil (Fig. 4).
Biology. The specimens were collected in several lentic habitats: in a large shallow marsh, in some shallow ponds with abundant macrophyte cover and in flooded banks of a river, in backwaters (Fig. 5).
Taxonomic comments. Crenitulus clarksoni sp. n. is close to C. suturalis (LeConte, 1866), C. hirsutus (Komarek, 2005), C. attiguus (d’Orchymont, 1942) and C. perpennus (Orchymont, 1942) in the combination of the following characters: antennae with nine antennomeres; antennomere 9 slightly longer than wide; procoxae with strong spines; dense pubescence of metafemur reduced to anterobasal portion; phallobase ca. as long as parameres and parameres acute apically. It differs from all of them by the combination of the mesoventrite nearly flat, only with slightly elevated posteromedian portion and the large spines of procoxae much longer than in the all other Crenitulus species. Apart from that, the new species differs from C. attiguus by the smaller length of body (1.6–1.8 mm; 2.1–2.4 mm in C. attiguus), pattern of femoral pubescence, presence of dorsal pubescence (absent in C. attiguus) and male aedeagus, with the phallobase larger than in C. attiguus and median lobe with outer margin almost parallel (slightly tapering towards apex in C. attiguus). Crenitulus clarksoni sp. n. differs from C. hirsutus in the shorter apical antennomere (longer in C. hirsutus), presence of longitudinal rows of coarser punctures on lateral margins of elytra (absent in C. hirsutus), apical and second maxillary palpi longer (shorter in C. hirsutus), pattern of femoral pubescence and male genitalia shape, with the parameres not pointed apically (pointed in C. hirsutus).
Crenitulus clarksoni sp. n. differs from C. suturalis in the apical antennomere shorter (longer in C. suturalis), presence of longitudinal rows of coarser punctures on lateral margins (absent in C. suturalis) and male genitalia shape, with phallobase as long as parameres (longer than parameres in C. suturalis), parameres almost straight on inner margin (slightly convex in in C. suturalis) and median lobe with outer margin almost parallel (slightly tapering towards apex in C. suturalis). The new species differs from C. perpennus in the shape of maxillary palpi, with the apical palpomere longer (shorter in C. perpennus) and the second palpomere 2 times longer than wide (1.5 times longer than wide in C. perpennus) and in the male genitalia shape, with outer margin of median lobe parallel, continuous (discontinuous in C. perpennus).
description: Published as part of Pes, Ana Maria, 2017, A new species of Crenitulus Winters, 1926 (Coleoptera: Hydrophilidae: Chaetarthrinae: Anacaenini) from northern South America, pp. 169-176 in Zootaxa 4319 (1) on pages 170-175, DOI: 10.11646/zootaxa.4319.1.9, http://zenodo.org/record/888683