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Research Article
Redescriptions and lectotype designations of Central American species of Phaenonotum Sharp (Coleoptera, Hydrophilidae) based on the type material from the David Sharp collection
expand article infoAlbert Deler-Hernández, Martin Fikácek§
‡ Charles University, Prague, Czech Republic
§ National Museum, Prague, Prague, Czech Republic
Open Access

Abstract

In order to understand the identity of the Central American species of the genus Phaenonotum Sharp, 1882, the type specimens of the species described by Sharp (1882) deposited in the David Sharp collection in the Natural History Museum in London have been re-examined. The following species are redescribed: Phaenonotum apicale Sharp, 1882, P. collare Sharp, 1882, P. dubium Sharp, 1882 (confirmed as junior synonym of P. exstriatum (Say, 1835)), P. laevicolle Sharp, 1882, P. rotundulum Sharp, 1882 and P. tarsale Sharp, 1882. Lectotypes are designated for P. apicale, P. collare, P. rotundulum and P. tarsale. External diagnostic characters and morphology of male genitalia are illustrated. A table summarizing diagnostic characters allowing the identification of the species is provided.

Resumen

Para entender la identidad de las especies del género Phaenonotum Sharp, 1882 de América Central, se han reexaminado los especímenes tipo de las especies descritas por Sharp (1882) depositadas en la colección de David Sharp, del Museo de Historia Natural en Londres. Las especies redescritas son: Phaenonotum apicale Sharp, 1882, P. collare Sharp, 1882, P. dubium Sharp, 1882 (confirmado como sinónimo más reciente de P. exstriatum (Say, 1835)), P. laevicolle Sharp, 1882, P. rotundulum Sharp, 1882 y P. tarsale Sharp, 1882. Se designan lectotipos para las especies Phaenonotum apicale, P. collare, P. rotundulum y P. tarsale. Se ilustran los caracteres diagnósticos y la morfología de los genitales. Una tabla resumen con los caracteres diagnósticos para facilitar la identificación de las especies es ofrecida.

Keywords

Coelostomatini, morphology, Neotropical region, Sphaeridiinae, taxonomy

Palabras clave

Coelostomatini, morfología, Neotrópico, Sphaeridiinae, taxonomía

Introduction

The genus Phaenonotum Sharp, 1882 was described by the British specialist on water beetles, David Sharp, in his treatment of the Central American hydrophilid fauna in the famous Biologia Centrali–Americana. Based on material from Mexico, Nicaragua, Guatemala, Costa Rica and Panama available to him, Sharp (1882) recognized and described six species of that genus, and also recognized that the North American species Cyclonotum exstriatum (Say, 1835) is congeneric. A few other species originally described in other genera were later assigned to Phaenonotum by other authors (Knisch 1924; Orchymont 1937) and few additional species were described subsequently from Brazil (Orchymont 1937, 1943), Argentina (Bruch 1915), Venezuela (Archangelsky 1989), U.S.A (Smetana 1978) and Cuba (Deler-Hernández et al. 2013). In addition, the monotypic genus Hydroglobus Knisch, 1921 from Argentina was considered a part of Phaenonotum by Archangelsky (1991), but this was not followed by subsequent authors (see e.g. Clarkson et al. 2014 for diagnostic characters between Hydroglobus and Phaenonotum). At present, Phaenonotum seems to occur exclusively in the Neotropical and southern Nearctic Region from where 18 species are described (Hansen 1999; Deler-Hernández et al. 2013). The identity of the only non-American species, P. africanum Régimbart, 1907 from the island of Bioko in Guinean Gulf, Africa, is unclear and the species needs to be re-examined.

Despite being frequently collected, Phaenonotum species were never properly revised, and only the fauna of North America and Argentina (partly) were treated in details by modern authors (Smetana 1978; Archangelsky 1991). Hence, no information on morphology of the species or identity of their types was published for the majority of species after their original descriptions, which makes the identification of newly collected material almost impossible. The only species for which types were reexamined and redescriptions and/or illustrations published are P. argentinense Bruch, 1915, P. regimbarti Bruch, 1915, and P. exstriatum (Say, 1835) and its synonyms (Smetana 1978; Archangelsky 1991). In addition, the lectotype of P. laevicolle Sharp, 1882 was designated by Smetana (1976), but without providing any information about the identity of that species. Of the recently described species, photos of the habitus and genitalia, and some details on morphology of P. minor Smetana, 1978 were published by Deler-Hernández et al. (2013). The assignment of P. caribense Archangelsky, 1989 to Phaenonotum was found questionable based on preliminary molecular data (A. Deler-Hernández & V. Sýkora, unpubl. data).

In the course of the review of Phaenonotum from the Greater Antilles, it was necessary to study the identities of the Central American species of the genus described by D. Sharp in order to confirm or exclude their occurrence in the Caribbean islands. The type series of all species described by Sharp and deposited in the Natural History Museum in London were therefore re-examined. To facilitate future studies, the results of these studies are summarized in the present paper, providing the redescriptions and illustrations of the species examined. In needed cases, the lectotypes have been designated in order to fix the identity of the species for future studies.

Material and methods

Habitus photographs were taken using Canon EOS 550D digital camera with attached Canon MP-E65mm f/2.8 1–5× macro lens, and subsequently adapted in Adobe Photoshop CS5. Drawings of male genitalia are based on photographs taken using Canon EOS 1100D digital camera attached to Olympus BX41 compound microscope and subsequently combined in Helicon Focus software. Scanning electron micrographs of lectotypes were taken using Hitachi S-3700N environmental electron microscope at the Department of Paleontology, National Museum in Prague, using the uncoated specimens in low vacuum regime. Morphological terminology follows Smetana (1978), Archangelsky (1989, 1991) and Deler-Hernández et al. (2013).

Part of the specimens including the lectotypes were dissected, their genitalia were mounted in an alcohol soluble Euparal resin on a small piece of glass attached to the same pin as the specimen.

All lectotypes designated were labeled with the following red label: “Lectotype [or Paralectotype] / Phaenonotum / species-name with author and year of description / des. Deler-Hernández”.

Under each species listed as material examined label data are given verbatim between quotes (“ ”), each line of text is separated by a slash with spaces on both sides (/) and the information of each label is separated by double slashes with space on both sides (//). Other data are in square brackets ([]).

Examined specimens are deposited in the following collections:

BMNH The Natural History Museum, London, U.K. (M. Barclay)

NMPC National Museum, Prague, Czech Republic (M. Fikáček)

Taxonomy

Phaenonotum apicale Sharp, 1882

Figures 1a, 2a, 3a, 4a

Phaenonotum apicale Sharp, 1882: 98.

Type material examined

Lectotype (hereby designated): male (BMNH): “Phaenonotum / apicale Var. / D.S. / Guatemala City. / 5000 ft. Salvin. // Guatemala City. Champion. // B.C.A. I. 2. / Phaenonotum / apicale, Sharp. // Sharp Coll. 1905.-313.” The specimen was re-mounted to a new label, with abdomen glued separately and aedeagus embedded in Euparal slide attached below the specimen. Paralectotype: female (BMNH): “Phaenonotum / apicale / Type / D.S. / Chontales, Nicaragua / Janson. // Chontales, / Nicaragua. / Janson. // B.C.A. Col. I. 2. / Phaenonotum / apicale, / Sharp. // Sharp Coll. / 1905.-313.”.

Other material examined

1 unsexed specimen (BMNH): “Phaenonotum / apicale Var.? / David. Chiriqui / Champion // David, / Panama / Champion. // B.C.A. Col. I. 2. / Phaenonotum / apicale, / Sharp. // Sharp Coll. / 1905.-313.”; 1 unsexed specimen (BMNH): “Cuernavaca, / Morelos. / Hoge. // B.C.A. Col. I. 2. / Phaenonotum / apicale, / Sharp. // apicale / var, [hand written]”; 1 unsexed specimens (BMNH): “Tejupilco, Mex. / Temescaltepec / 18.vi.1933 [hand written] // H. E. Hilton, / R. L. Usinger / Collectors”; male (BMNH): “Tejupilco, Mex. / Temescaltepec / 18.vi.1933 [hand written] // H. E. Hilton, / R. L. Usinger / Collectors // Phaenonotum [hand written] / apicale Sharp [hand written] / J. Balfour-Brown det.”.

Type locality

(following lectotype designation). Guatemala City, 5000 feet [= 1525 m a.s.l.], Guatemala.

Redescription

Habitus as in Figs 1a and 2a. Body length 2.9–3.2 mm (lectotype: 2.9 mm). Body form oval in dorsal view (Fig. 1a), elytra uniformly convex in lateral view (Fig. 2a). Dorsal surface dark brown (Fig. 1a). Antennae and maxillary palpi testaceous. Ventral surface reddish. Leg reddish, tarsomeres yellowish. Head and pronotum with fine and sparse punctures. Elytral punctation strongly impressed, coarser than pronotal and head punctation. Pronotum wider than long and convex. Epipleura very broad throughout. Meso- and metaventral processes fused into a common keel; mesoventral process arrow-head shaped with a distinct hood, as wide as metaventral process basally, metaventral process slender, parallel-sided, length of metaventrite medially (including metaventral process) ca. four times longer than mesoventral process; metathoracic discrimen indistinct (Fig. 3a). Profemora with long sparse pubescence in basal 0.75. Meso- and metafemora with very sparse and short pubescence only. All tarsi with long setae on ventral surface. Aedeagus (Fig. 4a) 0.4 mm long, with median lobe reaching apices of parameres; basal portion of median lobe angulate laterally, apical portion strongly narrowing; shape of the gonopore oval. Parameres wide and curved in median region. Phallobase not examined in detail.

Figure 1.

Habitus of type specimens (dorsal view) and original type labels. a Phaenonotum apicale Sharp (lectotype) b Phaenonotum collare Sharp (lectotype) c Phaenonotum dubium Sharp (lectotype) d Phaenonotum laevicolle Sharp (lectotype) e Phaenonotum rotundulum Sharp (lectotype) f Phaenonotum tarsale Sharp (lectotype).

Figure 2.

Habitus (lateral view). a Phaenonotum apicale Sharp (lectotype) b Phaenonotum collare Sharp (lectotype) c Phaenonotum laevicolle Sharp (lectotype) d Phaenonotum rotundulum Sharp (lectotype) e Phaenonotum tarsale Sharp (lectotype).

Figure 3.

Meso-metaventral process. a Phaenonotum apicale Sharp (Lectotype) b Phaenonotum collare Sharp (Lectotype) c Phaenonotum laevicolle Sharp (Lectotype) d Phaenonotum rotumdulum Sharp (Lectotype) e Phaenonotum tarsale Sharp (Lectotype) f Phaenonotum exstriatum (Say).

Figure 4.

Aedeagus. a Phaenonotum apicale Sharp (Lectotype) b Phaenonotum collare Sharp (Lectotype) c Phaenonotum dubium Sharp (Lectotype) d Phaenonotum exstriatum (Say) (specimen from Haiti) e Phaenonotum laevicolle Sharp (Lectotype) f Phaenonotum rotundulum Sharp (Lectotype) g Phaenonotum tarsale Sharp (Lectotype).

Comments on lectotype designation

Sharp (1882) mentions specimens from two localities: Nicaragua: Chontales and Guatemala: Guatemala City, but without specifying the number of specimens. In the Sharp collection, there are two specimens standing under the name of P. apicale, one from each locality mentioned, and both corresponding with the data in the original description. We hence consider both as syntypes. The specimen from Guatemala City is the only male, and thus is designated here as lectotype, despite it appearing to be slightly teneral. Otherwise, there are four specimens from localities not corresponding to those given in the original description, which we do not consider as a part of the type series (see Other material examined).

Phaenonotum collare Sharp, 1882

Figures 1b, 2b, 3b, 4b

Phaenonotum collare Sharp, 1882: 99.

Type material examined

Lectotype (hereby designated): male (BMNH): “Phaenonotum / collare D.S. // Chontales, / Nicaragua. / Janson. // B.C.A. I. 2. / Phaenonotum / collare, / Sharp. // Sharp Coll. 1905.-313.”. The specimen was dissected, its abdomen is glued separately and the aedeagus is embedded in Euparal slide attached to the same pin. Paralectotypes: 1 female, 1 unsexed (BMNH): “Phaen / Cyclonotum / collare D.S. / Type / Chontales. Nicaragua. / Janson // B.C.A. I. 2. Phaenonotum / collare, Sharp. // Sharp Coll. 1905.-313.”; “Phaenonotum / collare D.S. / Chontales. Nicaragua. / Janson / B.C.A. I. 2. Phaenonotum / collare, Sharp. / Sharp Coll. 1905.-313.”.

Other material examined

unsexed specimen (BMNH): “Phaenonotum / collare Var. / D.S. / El Zumbador / 2500 ft. Champion // El Tumbador, / Guatemala. / Champion. // B.C.A. I. 2. / Phaenonotum / collare, / Sharp. // Phaenonotum collare [hand written]”.

Type locality

(following lectotype designation). Chontales, Nicaragua.

Redescription

Habitus as in Figs 1b and 2b. Body length 3.5–3.9 mm (lectotype: 3.9 mm). Body form oval in dorsal view (Fig. 1b), elytra less convex anteriorly and more convex posteriorly in lateral view (Fig. 2b). Dorsal surface brown (Fig. 1b). Antennae and maxillary palpi testaceous. Ventral surface reddish brown. Leg reddish, tarsomeres yellowish. Head with coarse and strongly impressed punctures. Pronotum with fine punctures, but sparser than head punctation. Elytral punctation (Fig. 1b) strongly impressed, punctures of the same size as on head and as coarse as head punctations. Epipleura very broad throughout. Meso- and metaventral processes slender and fused into a common keel; mesoventral process arrow-head shaped with an distinct hood, slightly wider than apex of metaventral process basally, metaventral process slender, nearly parallel-sided, only indistinctly narrowing anteriad, length of metaventrite medially (including metaventral process) ca. four time longer than mesoventral process; metathoracic discrimen distinct, forming a shallow impression basally (Fig. 3b). All tarsi with long setae on ventral surface. Aedeagus (Fig. 4b) 0.4 mm long, with median lobe reaching apices of parameres; basal portion of median lobe rounded laterally, apical portion widely rounded, median lobe narrowing towards apex; shape of the gonopore transversely oval. Parameres wide and slightly sinuate in median region. Phallobase as long as wide.

Comments on lectotype designation

Sharp (1882) mentions specimens from two localities: Nicaragua: Chontales and Guatemala: El Tumbador, without specifying the numbers of specimens. Specimen(s) from Guatemala are assigned to the “var. paulo angustior” [= a little narrower], which excludes them from the type series based on Article 72.4.1 of the Code (ICZN 1999). In the Sharp collection, there are four specimens under the name Phaenonotum collare, three of which correspond to the Nicaraguan specimens mentioned in the original description, and one corresponding with “var. paulo angustior”. Only the specimens from Nicaragua are considered as part of the type series, and one of them, a dissected male, is designated as a lectotype, in order to fix the identity of the species for future studies.

Phaenonotum dubium Sharp, 1882 (= P. exstriatum (Say, 1835))

Figures 1c, 4c

Hydrophilus exstriatus Say 1835: 171. Trasferred to Phaenonotum by Sharp (1882: 98).

Phaenonotum dubium Sharp, 1882: 98. Synonymized with P. exstriatum by Smetana (1978: 14).

For complete synonymy of P. exstriatum see Hansen (1999).

Type material examined

Lectotype (designated by Smetana 1978: 14): male (BMNH): “Phaen / cyclonotum / dubium / D.S. / S. Geronimo. / Guatemala / Champion // B.C.A. I. 2. / Phaenonotum / dubium, / Sharp. // S. Geronimo. / Guatemala / Champion. // LECTO- / TYPE [round label with purple margins]”. Paralectotype: 1 unsexed specimen (BMNH): “Phaen / Cyclonotum / dubium / Types / D.S. / S. Geronimo. / Guate- / mala. Champion. // B.C.A. I. 2. / Phaenonotum / dubium, / Sharp. // San Geronimo. / Vera Paz. / Champion. // Type / H. T. [round label with red margins]”.

Other type material

Sharp (1882) also examined specimens from Mexico: Cordova, Vera Cruz, Oaxaca and Costa Rica: Cache, all of which have to be considered as paralectotypes. We did not examine these specimens.

Additional material examined

male (dry-mounted) (NMPC): CUBA: Granma Prov: Cauto Cristo, Río Cauto, El Sitio, 01.v.2005, Coll. L. Chaves. male (dry-mounted) (BMNH): HAITI: Port au Prince, 1.iii.1908, Coll. Dr. M. Cameron, B. M. 1936-555. male (dry-mounted) (BMNH): JAMAICA: Kinstong, 16.ii.1908, Coll. Dr. M. Cameron. male (dry-mounted) (BMNH): USA: Delaware (ABTC000175) (NMPC).

Type locality

San Geronimo, Guatemala.

Redescription

Habitus as in Fig. 1c. Body length 3.5–3.7 mm (lectotype: 3.5 mm). Body form oval in dorsal view (Fig. 1c), elytra convex in lateral view. Dorsal surface dark brown (Fig. 1c). Antennae and maxillary palpi testaceous. Pronotum slightly paler than elytra. Ventral surface reddish brown. Leg reddish, tarsomeres yellowish. Head with fine and sparse punctures. Pronotum with punctures of same size as on head. Elytral punctation strongly impressed, much denser than on pronotum and head. Epipleura very broad throughout. Meso- and metaventral processes fused into a common keel; mesoventral process arrow-head shaped with an distinct hood, as wide as metaventral process basally, metaventral process slender, parallel-sided, length of metaventrite medially (including metaventral process) ca. four times longer than mesoventral process; metathoracic discrimen indistinct (Fig. 3f). Profemora with long sparse pubescence in basal 0.75. All tarsi with long setae on ventral surface. Aedeagus (Fig. 4c) 0.4 mm long, with median lobe reaching apices of parameres or nearly so; basal portion of median lobe nearly straight laterally, apical portion widely rounded, median lobe nearly of the same width throughout; shape of the gonopore transversely oval. Parameres strongly sinuate in median region. Phallobase as long as wide (Fig. 4d).

Comments on synonymy

Examined type specimens of P. dubium morphologically correspond with specimens of P. exstriatum listed in “Additional material examined” in all characters, including morphology of the aedeagus and meso-metaventral process. Hence, we confirm that P. dubium is a junior synonym of P. exstriatum, as proposed by Smetana (1978).

Phaenonotum laevicolle Sharp, 1882

Figures 1d, 2c, 3c, 4e

Cyclonotum globulosum Mulsant, 1844: 167 (ascribed to Klug). [“Amérique méridionale”] (cf., Orchymont, 1937). Transferred to Phaenonotum by Knisch (1924: 114).

Phaenonotum laevicolle Sharp, 1882: 99. Considered as synonym of P. globulosum by Orchymont (1937: 241). Synonymy not confirmed by subsequent authors.

Type material examined

Lectotype (designated by Smetana 1976: 213): male (BMNH): “Phaenonotum / laevicolle / Type / D.S. / Cordova Mex Sallé. // B.C.A. I. 2. / Phaenonotum / laevicolle, / Sharp. // Sharp Coll. / 1905.-313.”. Paralectotype: male (BMNH): “Cubilguitz / Vera Paz. / Champion. // B.C.A. I. 2. / Phaenonotum / laevicolle, / Sharp”.

Other type material

Sharp (1882) also examined specimens from Nicaragua: Chinandega, Managua and Chontales, all of which have to be considered as paralectotypes. We did not examine these specimens.

Type locality

(following lectotype designation). Cordova, Mexico.

Redescription

Habitus as in Figs 1d and 2c. Body length 2.5–2.7 mm (lectotype: 2.7 mm). Body form oval in dorsal view (Fig. 1d), elytra evenly convex in lateral view (Fig. 2c). Dorsal surface brown (Fig. 1d). Antennae and maxillary palpi testaceous. Ventral surface reddish brown. Leg reddish, tarsomeres yellowish. Head with fine and sparse punctures. Pronotum with punctures of same size as on head. Elytral punctation strongly impressed, much coarser than pronotal and head punctation. Epipleura very broad throughout. Meso- and metaventral processes fused into a common keel; mesoventral process arrow-head shaped with narrow hood, its base narrower than apex of metaventrite; metaventral process stout, slightly widened subapically, length of metaventrite medially (including metaventral process) ca. three times longer than mesoventral process (Fig. 3c). All tarsi with long setae on ventral surface. Aedeagus (Fig. 4e) 0.5 mm long, with median lobe not reaching apices of parameres; basal portion of median lobe nearly straight laterally, apical portion widely rounded, median lobe narrowing towards apex; shape of the gonopore transversely subtriangular. Parameres wide and curved in median region. Phallobase not examined in detail.

Comments on synonymy

Orchymont (1937) considered P. laevicolle as a junior synonym of P. globulosum described from Colombia, based on the study of the type specimens of both taxa. However, he only compared external characters used for diagnosis of Phaenonotum species at that time (i.e. dorsal punctation, length of tarsi), and did not study ventral morphology and male genitalia, which are crucial characters for species identification. Smetana (1976) reexamined the types of P. laevicolle including genitalia, but he did not provide any comments on the synonymy proposed by Orchymont (1937), he neither studied the types of P. globulosum. For that reason, the synonymy of P. laevicolle with P. globulosum needs to be confirmed by future studies.

Phaenonotum rotundulum Sharp, 1882

Figures 1e, 2d, 3d, 4f

Phaenonotum rotundulum Sharp, 1882: 100.

Type material examined

Lectotype (hereby designated): male (BMNH): “Phaenonotum rotund– / ulum. / Type D.S. / S. Geronimo. Guatema– / la. Champion // San Geronimo, / Vera Paz. / Champion. // B.C.A. I. 2. / Phaenonotum / rotundulum, / Sharp. // Sharp Coll. / 1905.-313. // Type / H.T. [round label with red margins].” We remounted the specimens, the abdomen is glued separately, and the aedeagus is embedded in a Euparal slide attached to the same pin. Paralectotypes: 1 unsexed specimen (BMNH): “Phaenonotum / rotundulum / D.S. / El Zumbador. / 2500 ft. Guate– / mala. Champion. // El Tumbador, / Guatemala. / Champion. // B.C.A. I. 2. / Phaenonotum / rotundulum, / Sharp. // Sharp Coll. / 1905.-313.”. 1 unsexed specimen (BMNH): “Phaenonotum / rotundulum / D.S. / Chacoj. Guatema / la. Champion // Chacoj, / R. Polochic, / Guatemala. / Champion // B.C.A. Col. I. 2. / Phaenonotum / rotundulum, / Sharp.”. 2 females (BMNH): same label data as the lectotype.

Other type material

Sharp (1882) also examined specimens from Mexico: Cordova, Toxpam, Guatemala: San Juan, San Joaquin, Zapote, and Panama: Volcan de Chiriqui, 4000 to 6000 feet, all of which have to be considered as paralectotypes. We did not examine these specimens.

Type locality

(following lectotype designation). San Geronimo, Guatemala.

Redescription

Habitus as in Figs 1e and 2d. Body length approximately 2.8–3.3 mm (lectotype: 3.3 mm). Body form oval in dorsal view (Fig. 1e), elytra highly and evenly convex in lateral view (Fig. 2d). Dorsal surface reddish brown (Fig. 1e). Antennae and maxillary palpi testaceous. Ventral surface reddish brown. Leg reddish, tarsomeres yellowish. Head with fine and sparse punctures. Pronotum with punctures of same size as on head. Elytral punctation strongly impressed, much coarser than on pronotum and head. Epipleura very broad throughout. Meso- and metaventral processes fused into a common keel; mesoventral process arrow-head shaped with indistinct hood, its base as wide as apex of metaventral process, metaventral process wide basally, strongly narrowing anteriad and hence triangular in shape, length of metaventrite medially (including metaventral process) ca. three time longer than mesoventral process; metathoracic discrimen weakly developed (Fig. 3d). Profemora with long sparse pubescence in basal 0.75. All tarsi with long setae on ventral surface. Aedeagus (Fig. 4f) 0.5 mm long, with median lobe not reaching apices of parameres; basal portion of median lobe curved laterally, apical portion widely rounded, median lobe narrowing towards apex; shape of the gonopore oval. Parameres slightly sinuate in median region. Phallobase not examined in detail.

Comments on lectotype designation

Our request to borrow the Sharp specimens of P. rotundulum resulted in the receipt of the above five specimens. These specimens, however, clearly represent only a smaller part of the type series, as many other localities were mentioned in the original description by Sharp (1882). All specimens examined agree with the data provided in the original description, and hence are clearly part of the type series. In order to fix the identity of the species for future studies, we are designating the dissected male labeled as “Type” as the lectotype of P. rotundulum.

Phaenonotum tarsale Sharp, 1882

Figures 1f, 2e, 3e, 4g

Phaenonotum tarsale Sharp, 1882: 98.

Type material examined

Lectotype (hereby designated): male (BMNH): “Phaenonotum / tarsale D.S. / Panama. // B.C.A. Col. I. 2. / Phaenonotum / tarsale, / Sharp. // Panama. // Sharp Coll. / 1905.-313.” We remounted the specimen on a new label, with abdomen glued separately and aedeagus embedded in Euparal slide attached on the same pin. Paralectotypes: 1 male, 2 unsexed specimens (BMNH): same label data as the lectotype.

Type locality

(following lectotype designation). Panama.

Redescription

Habitus as in Figs 1f and 2e. Body length 4.7–4.8 mm (lectotype: 4.8 mm). Body form oval in dorsal view (Fig. 1f), elytra highly and evenly convex in lateral view (Fig. 2e). Dorsal surface dark brown (Fig. 1f). Antennae and maxillary palpi testaceous. Pronotum slightly paler than elytra. Ventral surface reddish brown. Leg reddish, tarsomeres yellowish. Head with fine and sparse punctures. Pronotum with punctures of same size as on head, but slightly more sparsely than the head. Elytral punctation strongly impressed, much denser than on pronotum and head. Epipleura very broad throughout. Meso- and metaventral processes fused into a common keel; mesoventral process arrow-head shaped, very wide basally, slightly hooded apically, its base slightly wider than apex of metaventral process, metaventral process stout, parallel-sided, length of metaventrite medially (including metaventral process) ca. three time longer than mesoventral process; metathoracic discrimen weakly developed (Fig. 3e). Profemora with long sparse pubescence in basal 0.75. All tarsi with long setae on ventral surface. Aedeagus (Fig. 4g) 0.7 mm long, with median lobe slightly overlapping apices of parameres; basal portion of median lobe nearly straight laterally, apical portion widely rounded, median lobe nearly of the same width throughout; shape of the gonopore rounded. Parameres slightly sinuate in median region. Phallobase slightly longer than wide.

Comments on lectotype designation

Our request to borrow the Sharp specimens of P. tarsale resulted in the receipt of the above four specimens, all of them corresponding with the original description and clearly part of the type series. In order to fix the identity of the species for future studies, we are designating the dissected male as the lectotype of P. tarsale.

Discussion

The identification of species of Phaenonotum is a difficult task, due to the similarity of the species and the complicated process of finding relevant morphological characters. This may explain the absence of keys to Phaenonotum species. Studies on Phaenonotum from Central America, together with preliminary studies on this genus in the Caribbean and South America (Deler-Hernández, unpublished data) show that reliable identification is possible based on several external morphological characters, especially the morphology of the meso-metaventral process. This structure exhibits some variation between species, especially in the shape of the metaventral process, the width of the mesoventral process, and the “size” of the apical hood of the mesoventral process (Table 1; Fig. 3; figs 10–12 in Deler-Hernández et al. 2013; figs 230–231 in Smetana 1978). Male genitalia, though very similar at first view, provide the most important characters for species identification, such as the shape of the apex and the base of the median lobe, the shape and position of the gonopore, and the shape of the external margin of the parameres (Fig. 4). Body size is also helpful in some cases, allowing the separation of species with rather similar male genitalia. Traditional characters used by previous authors (e.g. Sharp 1882; Smetana 1978), i.e. the dorsal coloration and punctation of pronotum and elytra, are insufficient for a reliable identification, although may be helpful when used in combination with those of the meso-metaventral elevation and the aedeagus.

Diagnostic characters of the Phaenonotum species described by D. Sharp.

P. apicale P. collare P. exstriatum (= P. dubium) P. laevicolle P. rotundulum P. tarsale
Total body length 2.9–3.2 mm 3.5–3.9 mm 3.5–3.7 mm 2.5–2.7 mm 2.8–3.3 mm 4.7–4.8 mm
Shape of mesoventral process arrow-head shaped with a distinct wide hood arrow-head shaped with a distinct wide hood arrow-head shaped with a distinct wide hood arrow-head shaped with distinct narrow hood arrow-head shaped with indistinct hood arrow-head shaped, slightly hooded apically
Base of mesoventral process as wide as apex of metaventral process slightly wider than apex of metaventral process as wide as apex of metaventral process narrower than apex of metaventral process as wide as apex of the metaventral process slightly wider than apex of metaventral process
Metaventral process slender, subparallel-sided slender, subparallel-sided slender, subparallel-sided stout, slightly widened subapically stout, wide basally, narrowing apically stout, parallel-sided
Aedeagus: length of parameres 0.4 mm 0.4 mm 0.4 mm 0.5 mm 0.5 mm 0.7 mm
Aedeagus: length of median
lobe
reaching apices of parameres reaching apices of parameres reaching apices of parameres or nearly so not reaching apices of parameres not reaching apices of parameres slightly overlapping apices of parameres
Aedeagus: basal region of the median lobe laterally angulate rounded nearly straight nearly straight slightly curved basally nearly straight
Aedeagus: apical region of the median lobe strongly narrowing widely rounded widely rounded widely rounded widely rounded widely rounded
Aedeagus: shape of the parameres wide and curved in median region wide and slightly sinuate in median region strongly sinuate in median region wide and curved in median region slightly sinuate slightly sinuate
Aedeagus: shape of the gonopore oval transversely oval transversely oval transversely subtriangular oval rounded

Acknowledgements

We are indebted to Christine Taylor and Maxwell Barclay (both BMNH) for the opportunity to study the type specimens from the D. Sharp collection under their curatorship. The authors wish to thank Bruno Clarkson (Universidade Federal do Rio de Janeiro) and Miguel Archangelsky (LIESA – Universidad Nacional de La Patagonia) for comments and suggestions to improve the manuscript, as well as Robert S. Anderson (Canadian Museum of Nature, Ottawa) for improving the English. The study was supported by grant SVV 260 313/2016 to ADH and by the Ministry of Culture of the Czech Republic (DKRVO 2016/14, National Museum, 00023272) to MF.

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