Hydrophilus (Dibolocelus) pseudovatus Arce-Pérez & Arriaga-Varela, 2021

Arce-Pérez, Roberto, Arriaga-Varela, Emmanuel, Novelo-Gutiérrez, Rodolfo & Navarrete-Heredia, José L., 2021, Giant water scavenger beetles Hydrophilus subgenus Dibolocelus (Coleoptera Hydrophilidae) from Mexico with description of two new species, Zootaxa 5027 (3), pp. 387-407 : 392-393

Hydrophilus (Dibolocelus) pseudovatus Arce-Pérez & Arriaga-Varela sp. nov.

Figs. 3, 4 ; 11–14 , 41.

Etymology. Named H. (D.) pseudovatus (ancient Greek pseudes = false) in recognition of the external resemblance of this species to H. (D.) ovatus .

Type material (25♂, 14♀). Holotype male: MEXICO: Nayarit, San Blas, Matanchén, 80 m, 26.vii.2007, 21º30’ N, 105º14’ Oeste. G . Nogueira col. 1 ♂ ( IEXA) . Paratypes. San Blas 7.xi.1980, [21°32′23″N 105°17′08″O], M . Beltran col. 1 ♂; 6.xii.1980 M . Teresa Ortiz col. 1 ♂; 9.xii.1980, R . Arce col. 2 ♂ ( IEXA); San Blas 4.xi.1991, R . Barba y E . Barrera col. 5 ♂ ( CNIN), Guerrero, Técpan de Galeana, Papanoa xi.1970, [17°19′28″N 101°02′28″O] J . Hendrichs col. 1 ♂ ( CNIN), Técpan de Galeana, Tetitlán , [17°07′00″N 100°28′00″O], 19.xii.1981, V . Reyes col. 1 ♂ ( IEXA). Técpan de Galeana , 18.vi.1982, I . Abarca col. 1♂ ( IEXA). Colima, Tecomán, Tecomán, [18°54′32″N 103°52′29″O], xi.1970, 4♂, 5♀ (INIFAP-Celaya). Jalisco, Tomatlán , presa Cajón de Peñas , La Quebrada , BTC, 100 m, [19°56′3′′ N, 105°14’8′′ O], 12.x.1996, J. C . Rodríguez col. 1 ♂ ( CZUG); Punta Pérula , 19°36′18′′ N, 105°9’30’’ W, 28.x.1999, L. G . Martínez col. 1 ♀ ( CZUG); Punta Pérula , 19°37′27.1′′ N, 105°7′34.4′′ W, a la luz, 11.xi.1999, H. E . Fierros col. 2 ♂ ( CZUG) Chamela, Arroyo , [19°30′38″N 105°03′24″O], 13.x.1991, C . Mayorga y G . Ortega cols. 1 ♂ ( CNIN), Est. de Biol. Chamela , A . Pescador col. [19°30′38″N 105°03′24″O], 30.vii.1980 1 ♂ ( CNIN). Puebla, San José Acateno, Río Saltero , [20°08′00″N 97°12′00″O], 162 m, 19.vii.1999, G . Hernández col. 1 ♂ ( IEXA). Oaxaca, Putla Villa de Guerrero, [17°01′33″N 97°55′45″O] 740 m 12-vii.2013, Julian, H. C . col. 1 ♂ ( IEXA). Ve- racruz, Alto Lucero, 5 km. Norte de Palma Sola, 19°10′51″ N Longitud : 96°08′34″ O, 22.iv.1990, Luz Mercurial, F . Capistran y L . Delgado Cols. 2 ♀, Los Tuxtlas , [18° 35.11’ N, 95° 04 O], 130 m, 8.iv.1982, T . Ortiz Col. 1♀, Los Tuxtla, El Vigía, 700 m, 2/ 12.vii.1972 1♀, Tamiahua , Laguna de Tamiahua , [21°16′46″N, 97°26′49″O], 30.vii.1936, P . Roveglia 1♀, Jalcomulco, Bordes de selva mediana, [19°20′00″N 96°46′00″O], 380 m, 11.vi.2005 , Fdo. Escobar col. 1♀, Actopan, La Mancha, 19° 39N, 96° 27’O, 1♀ ( IEXA). Morelos, Jojutla , [18°36′53″N 99°10′49″O], 750 m, 1♀? ( CNIN) .

Diagnosis. The specimens of H. (D.) pseudovatus sp. nov. are very similar to those of H. (D.) ovatus from North America. The new species can be distinguished from H. (D.) ovatus because [the characters of H. (D.) ovatus are provided in brackets for comparative purposes the characters of H. (D.) ovatus ] third maxillary palpomere shorter and wider, curved towards apex, markedly flattened and broadened toward the apex, with 0.085 mm in its side wider ( Fig. 7 ) [third maxillary palpomere slightly flattened and broadened towards its apex, with its internal margin slightly convex (near 0.80 mm in its widest part) ( Fig. 11 )]; the fifth protarsomere shorter than basal tar- someres together, flat and with a slight but evident internal laminar expansion ( Fig. 12 ) [fifth protarsomere is long and wide, longer than the basal tarsomeres together, no internal expansion ( Fig. 8 )]; the metaventral spine shorter, not exceeding 3/4 of the second abdominal ventrite ( Figs. 4 , 13 ) [metaventral spine longer, reaches or exceeds the posterior margin of the second abdominal ventrite ( Figs. 2 , 9 )]; ventrites 3 and 4 slightly raised, with their apical margin slightly rounded and very slightly projecting over the following ventrite ( Fig. 13 ) [ventrites 3 and 4 raised, with their apical margin slightly acute and slightly projecting over the next ventrite ( Fig. 9 )]; abdominal ventrites without evident yellowish-reddish lateral oval spots [ventrites with evident yellowish-reddish lateral oval spots]; median lobe broad ( Fig. 14 ) [narrower in H. (D.) ovatus ( Fig. 10 )].

Description male holotype. Body elongated-fusiform, length 32–36 mm (male holotype: 35 mm), width 17– 17.5 mm at humeri (Holotype: 17 mm), 2× longer than wide, dorsally strongly convex and glabrous, ventrally flat and pubescent; dorsal color black with dark green tone; ventrally black with reddish yellowish hue, ventral vestiture pale yellow; antennae, palpi and legs dark-reddish ( Figs 3, 4 ).

Head: Antennae short with nine antennomeres, scape large and robust, longer than the next four antennomeres together, pedicel subequal to the following three antennomeres, sixth antennomeres long and oval, subequal to the previous four together, not covering the first article of antennal club ( Fig. 11 ). Maxillary palpi long and slender, with four palpomeres, with lengths: 0.04, 0.29, 0.27, 0.14 mm; first palpomere small, sub-conical, second long, curved, slightly broadened towards apex, third shorter and wider, curved towards apex, markedly flattened toward the apex, with 0.085 mm in its side wider, fourth short, oval, with truncated. Mentum hexagonal, 1.7× wider at base than long, lateral margins parallel at basal half, apically converging straightly, apex truncated and straight. Labial palpi short, length of palpomeres: 0.02, 0.09, 0.06 mm; first palpomere small and broad, second long and slightly broadened towards apex, 1.5× longer than the third, with short golden setae near the internal marginapex, third palpomere short and oval, with apex rounded ( Fig. 11 ).

Thorax: Prosternal lobes raised and apically rounded, with short reddish-yellow setae at apex; mesoventrite with keel long and narrow, with lateral margins rounded and convergent towards apex, with a broad and shallow concavity at basal 3/5, deeper near apex. Metaventrite with keel wide and flat, with feeble median longitudinal groove, ending as a long spine reaching half-length of the second abdominal ventrite ( Fig. 4 ). Elytra with four wellmarked rows of black spots, two on the disc, one sublateral starting after the humerus, and other more incomplete on the sides ( Fig. 3 ).

Legs: Anterior tibiae with two spurs; internal one shortest, flat, sub-rectangular with apex truncate straight, with a small notch close to the external margin; external spur longer, sub-triangular, acute; fifth protarsomere shorter than the previous ones together, broadly flattened, with a small but evident internal laminar expansion; tarsal claws curved, without basal tooth, internal claw slightly longer than external one, protarsomeres 2–5 with tufts of golden setae in the external margin ( Fig. 12 ).

Abdomen: Vestiture leaving a wide and long glabrous oval area at mid-line in ventrites 3–4; and a broader subrectangular one in ventrite 5. Ventrites 3 and 4 raised and flattened above, with apex rounded and slightly projected on the next ventrites ( Figs 4 , 13 ).

Genitalia: Total length 6.0 mm; phallobase long (length: 2.9 mm width 2.1 mm) narrow with apex of manubrium rounded; parameres long (length: 4.1 mm), broadened at basal 3/5, elongated-oval at apical 2/5, with a deep oval concavity not reaching the apex, with minute teeth in the internal margin at the apical half, getting more abundant apically. Median lobe slightly shorter than the parameres (3.7 mm), broad sub-triangular with rounded apex, with a median sulcus, apex rounded ( Fig. 14 a, b ).

Sexual dimorphism. Females similar to males but with palpi more slender, anterior tibiae with spurs elongate sub-triangular, tarsal claw long, curved and acute, with a basal acute tooth.

Variation. Body length 32–36 mm, humeral width 17.0–17.5, 18–2.0× longer than wide; coloration can be brown-reddish (in old specimens); sixth antennomere and antennal club can be reddish-yellow to dark red; average length of maxillary palpomeres: 0.04, 0.29, 0.26, 0.15 mm; average width third palpomere: 0.085 mm; average length of labial palpi: 1.8 mm; prosternal lobes with apex rounded to acute; internal spur of protibiae with apex truncate, sometimes without notch in the external margin.

Distribution. Mexico: Colima, Guerrero, Jalisco, Morelos, Nayarit, Oaxaca, Puebla, Veracruz (Fig. 41).

Taxonomic comments. Since this species differs from H. (D.) ovatus in characters of key taxonomic importance like the shape of male maxillary palps, the protarsal structure and the male genitalia we consider that these differences support the description of H. (D.) pseudovatus as a new species. However, both species seem to share a large part of its distribution in Mexico (Fig. 41). Furthermore, according to Andrew E.Z. Short (personal communication) some H. (D.) ovatus specimens from Veracruz, Mexico are somewhat intermediate in morphology with H. (D.) pseudovatus sp. nov. In order to fully elucidate the nature of the relation between these two species more sampling in Mexico is needed as well as to study their genetic information.

Figures

FIGURES 1–6. Dorsal and ventral view of Hydrophilus (Dibolocelus) spp. 1–2 H. (D.) ovatus Gemminger & Harold; 3–4 H. (D.) pseudovatus sp. nov.; 5–6 H. (D.) nucleoensis sp. nov.

FIGURES 7–18. Morphological structures and male genitalia of Hydrophilus (Dibolocelus) spp. 7-10 H. (D.) ovatus Gemminger & Harold; 7 ventral view of head (arrow: third labial palpomere); 8 protibia and tarsi, 9 ventral view of abdomen; 10a aedeagus ventral; 10b aedeagus dorsal; 11–14 H. (D.) pseudovatus sp. nov.; 11 ventral view of head(arrow: third labial palpomere); 12 protibia and tarsi, 13 ventral view of abdomen; 14a aedeagus ventral; 14b aedeagus dorsal; 15–18 H. (D.) nucleoensis sp. nov.; 15 ventral view of head (arrow: third labial palpomere); 16 protibia and tarsi, 17 ventral view of abdomen; 18a aedeagus ventral; 18b aedeagus dorsal.