Diomus leondai González, Ramos and Lemos, 2020

Ramos, Albéryca Stephany de Jesus Costa, González, Guillermo & Lemos, Raimunda Nonata Santos de, 2020, A new species of Diomus Mulsant (Coleoptera: Coccinellidae: Diomini) from the eastern Amazon, Revista Brasileira de Entomologia (e 20200014) 64 (4), pp. 1-5 : 2-4

publication ID	https://doi.org/ 10.1590/1806-9665-RBENT-2020-0014
persistent identifier	https://treatment.plazi.org/id/03928780-AE0B-FFA1-0718-FC5DFB9CCE5A
treatment provided by	Felipe
scientific name	Diomus leondai González, Ramos and Lemos
status	sp. nov.

Treatment

Diomus leondai González, Ramos and Lemos sp. nov.

( Fig. 1 View Figure 1 a-s).

Diagnosis: Diomus leondai sp. nov. presents a very common design, shared with various species of the genus, consisting of lightcolored elytra with a dark border covering the base, suture, and part of the lateral border ( Fig. 1a View Figure 1 ). It is distinguished from other Diomus species by the male genitalia, which agree with Gordon’s “F” group, primarily distinguished by having a long apical penis flagellum at least one-quarter the length of the penis ( Fig. 1o View Figure 1 ), parameres without apical modifications, and a basal lobe lacking a ventral membranous appendage ( Fig. 1k, 1n View Figure 1 ) ( Gordon 1999). In this group D. leondai can be distinguished by a penis guide with sclerotized apical teeth ( Fig. 1j View Figure 1 ), without dorsal keel ( Fig.1n View Figure 1 ) and with a median clump of setae ( Fig. 1l View Figure 1 ), a combination of characters not known for any other species in the group.

Description: Holotype male. Length: 1.5 mm. Width: 1.1 mm. Oval shape with maximum width at two-fifths of elytra length, with thin dorsal punctuation and yellow-colored dorsal pilosity ( Fig. 1a View Figure 1 ). Head shiny, yellowish-brown, finely punctured, punctures separated by about twice a diameter, frons slightly narrowed from vertex to clypeus, about 2.5 times eye width, mouthparts and antennae yellow ( Fig. 1c View Figure 1 ), apical maxillary palpomere securiform, antennae with 11 antennomeres. Pronotum yellowish brown, slightly dark reddish around the center of the base ( Figs. 1a, 1c View Figure 1 ), with punctures larger than on head, separated by little more than a diameter. Scutellum semicircular, reddish brown, bordered with dark brown.Elytra yellow, with broad basal border, lateral borders and triangular scutellar area dark brown, scutellar area extending posteriorly along the suture to apical declivity, narrowing from base to apex, lateral border extending posteriorly on lateral margin to apical twothirds ( Figs. 1a, 1 View Figure 1 d-e), punctures smaller than the pronotal punctures, separated by about twice a diameter.Ventral side yellowish-brown with dark brown pro-, meso-, and metasternum ( Fig. 1b View Figure 1 ). Prosternum “Y” shaped, apically emarginated, with prosternal carina extended to the apex. Metasternum postcoxal line complete, descending in semicircular curve, ending in lateral border two-fifths from base of length of sternum. Legs yellow ( Fig. 1c View Figure 1 ), with tarsi trimerous. Abdomen yellowish brown with the middle part of the first two ventrites dark brown ( Fig. 1b View Figure 1 ), with 6 ventrites, postcoxal line of first ventrite extending in curve to the hind margin of ventrite. Male genitalia with tegmen with sub-square phallobase ( Fig.1k View Figure 1 ) and penis guide with almost parallel sides in ventral view, triangular with convex edges in apical one-third, with sclerotized apical teeth ( Fig. 1l View Figure 1 ); in lateral view it is triangular, pointed apically with clump of dorsal setae, dorsal keel absent ( Fig. 1n View Figure 1 ). Parameres exceeding penis guide by one-third, widened from base to rounded apex ( Fig. 1k View Figure 1 ). Penis curved in basal three-quarters, sinuate near apex, with thin flagellum projecting along half penis length; penis capsule with slightly concave basal margin, reduced triangular outer arm, inner arm well-developed, perpendicular to the body, twice long as wide ( Fig. 1o View Figure 1 ). Apex of 5th ventrite deeply emarginated medially ( Fig.1h View Figure 1 ), 6th ventrite apex medially truncate ( Fig. 1i View Figure 1 ).

Female: Habitus and variations similar to male, genitalia ( Fig. 1q View Figure 1 ) with C-shaped spermatheca, broad at the base and narrowing toward the apex, ramus beaked ( Fig. 1s View Figure 1 ), coxites short, somewhat transverse, bearing styli ( Fig. 1r View Figure 1 ), 5th ventrite apex slightly truncate, 6th ventrite apically arcuate ( Fig. 1s View Figure 1 ).

Variation: Length: 1.2 – 1.5 mm. Width: 0.9 – 1.1 mm. Pronotum varying from indicated to a large dark brown basomedian spot, emarginated in lateral margins ( Fig. 1g View Figure 1 ). The dark elytral margins variable in extension, the color sometimes light brown and diffuse or may be missing, leaving only a reddish-yellow scutellar spot ( Fig. 1f View Figure 1 ).

Type material: Holotype male: “ BRASIL, MA [State of Maranhão], São José de Ribamar \ [02°50′S, 44°02′W] \ Em Hibiscus sabdariffa\ A.S.J.C. Ramos, ix.2016 ” “ CIPC \Ref. 755-75” ( DZUP) GoogleMaps . Paratypes: 12 females and 2 males: 3 females: same data as holotype ( DZUP) GoogleMaps ; 5 females and 1 male: “ BRASIL, MA [State of Maranhão], Raposa \ [02°46′S, 44°14′W] \ on Hibiscus acetosella\ A.S.J.C. Ramos, xi.2016 ” “ CIPC \Ref. 757-121” ( DZUP) GoogleMaps ; 4 females: same data as preceding ( DZUP) GoogleMaps ; 1 male “ BRASIL, MA [State of Maranhão], Paço do Lumiar [02°51′S, 44°09′W] \ Em Hibiscus sabdariffa\ A.S.J.C. Ramos, x.2017 ” “ CIPC \ Ref. 824 -84” ( DZUP). All type material with extracted genitalia in microvials GoogleMaps . Additional material: 54 specimens: 3 specimens: “ BRASIL, MA [State of Maranhão], São José Ribamar [02°50′S, 44°02′W] \ Em Hibiscus sabdariffa\ A.S.J.C. Ramos, vi.2017 ” “ CIPC \ Ref. 822-400” GoogleMaps ; 3 specimens: same data as preceding GoogleMaps ; 7 specimens: same data as preceding GoogleMaps except “ ix.2016 ” and “Ref. 823-69” ; 1 specimen: same data as preceding except “ ii.2018 ” and “Ref. 856-422” ; 1 specimen: same data as preceding except “ x.2017 ” and “Ref. 832-263” ; 2 specimens: “ BRASIL, MA [State of Maranhão], São José Ribamar [02°50′S, 44°02′W] \ Em Phenacoccus solenopsis\ em Hibiscus sabdariffa\ A.S.J.C. Ramos, xi.2017 ” “ CIPC \ Ref. 828-402” GoogleMaps ; 1 specimen: “ BRASIL, MA [State of Maranhão], Raposa [02°46′S, 44°14′W] \ Em Hibiscus sabdariffa\ A.S.J.C. Ramos, xi.2016 ” “ CIPC \ Ref. 821-122” GoogleMaps ; 2 specimens: same data as preceding GoogleMaps except “ xi.2016 ” and “Ref. 825-111” ; 1 specimen: same data as preceding except “ x.2017 ” and “Ref. 829-274” ; 2 specimens: same data as preceding except “Ref. 830-272”; 3 specimens: “ BRASIL, MA [State of Maranhão], São José Ribamar [02°50′S, 44°02′W] \ Em Solanum lycopersicum\ A.S.J.C. Ramos, x.2017 ” “ CIPC \ Ref. 797-88” GoogleMaps ; 1 specimen: same data as preceding GoogleMaps except “ iv.2017 ” and “Ref. 796- 182” ; 3 specimens: same data as preceding except “ xii.2016 ” and “Ref. 833-149” ; 15 specimens: same data as preceding ; 1 specimen: “ BRASIL, MA [State of Maranhão], Raposa [02°46′S, 44°14′W] \ Em Abelmoschus esculentus\ A.S.J.C. Ramos, v.2018 ” “ CIPC \ Ref. 751- 378” GoogleMaps ; 4 specimens: same data as preceding GoogleMaps except “ xi.2016 ” and “Ref. 811-124” ; 1 specimen: “ BRASIL, MA [State of Maranhão], Paço do Lumiar [02°51′S, 44°09′W] \ Em Abelmoschus esculentus\ A.S.J.C. Ramos, xi.2016 ” “ CIPC \ Ref. 756-117” GoogleMaps ; 1 specimen: “ BRASIL, MA [State of Maranhão], Raposa [02°46′S, 44°14′W]\ Em Capsicum spp. \ A.S.J.C. Ramos, v.2017 ” “ CIPC \ Ref. 804-194” GoogleMaps ; 1 specimen: same data as preceding GoogleMaps ; 1 specimen: “ BRASIL, MA [State of Maranhão], Paço do Lumiar [02°51′S, 44°09′W]\ Em Capsicum spp. \ A.S.J.C. Ramos, ix.2016 ” “ CIPC \ Ref. 805-232” ( CIPC) GoogleMaps .

Biology: Specimens were collected on the branches, leaves, and fruits ofAbelmoschus esculentus L. Moench, Hibiscus acetosella Welw. Ex Hiern, Hibiscus sabdariffa L.( Malvaceae ), Capsicum spp. , and Solanum lycopersicum L.( Solanaceae ). The specimens were observed feeding on Phenacoccus solenopsis Tinsley, 1898 and Phenacoccus sp.

Etymology: The name of the species is a reference to the first authorʹs grandfather. Leonda is the nickname of Leônidas.

Discussion: Diomus leondai n. sp. presents the typical characteristics of the genus mentioned above (see Diomus Mulsant, 1850 ). It also presents the characters typical of group “F” of Gordon (see diagnosis). It has the remarkable condition of having a lateral tooth at the apex of the tegmen ( Fig. 1j View Figure 1 ), a condition that is common in group “C” of Gordon, but very rare in group “F”, being present in only two other species, D. sylvester Gordon from Venezuela and D. soter Gordon, 1999 , from Pernambuco, Brazil; the latter presents 2 apical teeth ( Gordon, 1999). The combination of a clump of dorsal setae in the basal lobe ( Fig. 1l View Figure 1 ), together with the absence of dorsal keel ( Fig. 1l View Figure 1 ) is also a very rare combination, being present only in D. sussane Gordon, 1999 from Pernambuco, Brazil and D. symphorosa Gordon, 1999 from Colombia.

The description of a new species of Diomus increases the number of species for this genus in South America to 262. The persistent increase of new species of the genus during the last decade ( González and Honour, 2011; González, 2015, 2016), based on the review of very restricted material, points out that there could still be many species to discover. The geographic distribution of most South American species is barely known; as an example, about 140 species described by Gordon (1999) are known only from the type locality; the vast majority have a single specimen.

The work of Gordon (1999), with images and detailed descriptions of the genitalia of species and their distribution in groups (although not necessarily monophyletic) has been of great help in recognizing the species described. The absence of specialists in taxonomy has been a major obstacle for the genus to be better known.

The exploration of new regions and the study of existing collections will allow for the discovery of new species and improve the knowledge of the distribution of those already described. There is an almost universal ignorance of the biology of these species; notable are the contributions to myrmecophilous species ( Vantaux et al., 2010; Vandenberg et al., 2018), but these are atypical species, and knowledge of the rest of the species that feed mainly on Pseudococcidae is reduced almost exclusively to a few records of prey taken from the labels.

Although in South America the genus appears quite well defined and homogeneous, Vandenberg and Hanson (2019) noted that Australian species cannot be assigned to any of the groups defined for South America ( Gordon, 1999) and pointed out the need to continue investigating the morphological aspects of the genus globally, and develop molecular studies to discern problems not yet resolved. It should be noted that the genera present in the tribe Diomini appear well-differentiated and defined ( Vandenberg and Hanson, 2019).

A phylogenetic analysis that considers feed, as well as morphological, molecular, and biogeographic characteristics could find that some of these genera only constitute secondary branches of the genusDiomus, (and therefore do not justify their generic category), or that Diomus , in turn, has separate lineages that deserve to be considered genera by themselves. This study is pending.