Revision of type specimens of Astaena (Coleoptera: Scarabaeidae: Melolonthinae: Sericini) described by L.W. Saylor

Thaynara L. PACHECO 1,*, Marcela L. MONNÉ 2, Fernando Z. VAZ-DE-MELLO 3 & Dirk AHRENS 4 1 Laboratório de Coleoptera, Departamento de Entomologia, Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. 1,4 Centre of Taxonomy and Evolutionary Research, Zoologisches Forschungsmuseum Alexander Koenig, Bonn, Germany. 2 Laboratório de Coleoptera, Departamento de Entomologia, Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. 3 Laboratório de Scarabaeoidologia, Departamento de Biologia e Zoologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá, Brazil.


Introduction
Sericini Kirby, 1837 is a monophyletic tribe of chafer beetles with a nearly worldwide distribution, that is absent only in Australia and circumpolar regions (Ahrens 2006a;Eberle et al. 2017a). It comprises about 4000 species allocated in 200 genera (Ahrens 2006a). While Sericini are still generally poorly known in terms of their taxonomy and systematics, some signifi cant progress has been made over the past two decades with hundreds of new species of Sericini discovered in Asia and Africa (e.g., Ahrens 2004a; Fabrizi & Ahrens 2014;Ahrens & Fabrizi 2016;Eberle et al. 2017b;Fabrizi et al. 2019aFabrizi et al. , 2019bLiu et al. 2019). However, South American species are still comparatively poorly known . For South America, around 250 nominal taxa have been described previously. The latest comprehensive treatment was a synopsis by Frey (1973). However, the recognition of most species is still very diffi cult since many species have been described based on female specimens and so far, comprehensive illustrations of species morphology are scarce.
This work is part one of a series of studies with the common goal to re-examine and redescribe the type specimens of species of Sericini from South America, to designate lectotypes or neotypes where necessary, to revise their taxonomic status, and to produce high-quality images from the type specimens and their labels. In this way, we hope to facilitate correct identifi cation of the species for future work, thus increase our ability to recognize as yet undescribed species, and make taxonomic information available for applied research including ecological, phylogenetic and biogeographical issues.
Most South American species of Sericini were described by German entomologists, such as Erichson (1835Erichson ( , 1847, Burmeister (1855), Kirsch (1865Kirsch ( , 1885, Moser (1918Moser ( , 1921aMoser ( , 1921bMoser ( , 1924Moser ( , 1926, and Frey (1973Frey ( , 1974Frey ( , 1975Frey ( , 1976, and their type specimens are housed in European collections (Evans 2003). However, numerous species were described by Lawrence W. Saylor (1913Saylor ( -1999Ratcliff e 2016). During the visit of the fi rst author (TLP) to the United States National Museum, Smithsonian Institute, Washington DC (USNM), it was possible to borrow and examine the Saylor type specimens of Sericini from the Californian Academy of Sciences, thus facilitating the fi rst part of this taxonomic revision. Here we revise the type material of 18 species (of 19 total species in total) of South American Sericini described by L.W. Saylor, providing redescriptions and systematic assessments of the species. Raysymmela huanuca Saylor, 1947(Saylor 1947a was not included in this work. It will be treated in the framework of a separate revision of this genus.

A
. Lateral carina present. Second visible ventrite with row of setae in medial region. Apical visible ventrite without suture to apical tergite.

A
. Lateral carina present. Second visible ventrite with row of setae in medial region. Apical visible ventrite without suture to apical tergite.
L . Ratio of length of metepisternum / metacoxa: 1/0.77. Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf present. Metatibia, widest at apex, ratio of width / length: 1/2.69, dorsal margin not carinated, ventral margin not serrated, distal spines groups disposed at two thirds of metatibial length. First metatarsomere, ratio to dorsal metatibial spur 1/2. Dorsal surface of tarsi glabrous and without punctures. Metatarsi, length of fi rst protarsomere smaller than second and third combined, ventral margin not serrated and setose. Protibia with three teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow, claws symmetrical, inner protarsal claw bifi d, apex of basal tooth of inner protarsal claw acute.

A
. Lateral carina present. Apical visible ventrite without suture to apical tergite.
L . Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf present. Metatibia, widest at apex, distal spines groups disposed at two thirds of metatibial length. First metatarsomere, ratio to dorsal metatibial spur 1/3. Metatarsi, length of fi rst protarsomere smaller than second and third combined, ventral margin serrated and setose. Protibia with three teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow, claws symmetrical, inner protarsal claw bifi d, apex of basal tooth of inner protarsal claw acute.

A
. Lateral carina present. Second visible ventrite without row of setae in medial region. Apical visible ventrite without suture to apical tergite.
L . Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf present. Metatibia, widest at apex, dorsal margin not carinated, ventral margin serrated, distal spines groups disposed at two thirds of metatibial length. First metatarsomere, ratio to dorsal metatibial spur: 1/2. Dorsal surface of tarsi glabrous, without punctures. Metatarsi, length of fi rst protarsomere smaller than second and third combined, ventral margin serrated and setose. Protibia with three teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow, claws symmetrical, inner protarsal claw bifi d.

Male
Unknown.

Remarks
The holotype specimen is a female; Saylor (1946) incorrectly stated that the holotype as a male. Saylor, 1947 Figs 2E-I, 7A

A
. Lateral carina present. Second visible ventrite without row of setae in medial region. Apical visible ventrite without suture to apical tergite. L . Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf absent. Metatibia, widest at apex, dorsal margin carinated, distal spines groups disposed at two thirds of metatibial length. First metatarsomere, ratio to dorsal metatibial spur: 1/3. Dorsal surface of tarsi glabrous, with punctures. Metatarsi, length of fi rst protarsomere subequal to second and third combined, ventral margin serrated. Protibia with three teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow, claws symmetrical, inner protarsal claw bifi d, apex of basal tooth of inner protarsal claw acute.

A
. Lateral carina present. Second visible ventrite with row of setae in medial region. Apical visible ventrite without suture to apical tergite.
L . Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf present. Metatibia, widest at apex, dorsal margin carinated, with group of spines positioned at two thirds of metatibial length. First metatarsomere, ratio to dorsal metatibial spur: 1/3. Dorsal surface of tarsi glabrous. Metatarsi, length of fi rst protarsomere smaller than second and third combined, ventral margin serrated and setose. Protibia with three teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow, claws symmetrical, inner protarsal claw bifi d, apex of basal tooth of inner protarsal claw acute.

A
. Lateral carina absent. Second visible ventrite without row of setae in medial region. Apical visible ventrite without suture to apical tergite.

A
. Lateral carina present. Second visible ventrite with row of setae in medial region. Apical visible ventrite without suture to apical tergite.
L . Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf present. Metatibia, widest at apex, dorsal margin not carinated, distal spines groups disposed at two thirds of metatibial length. First metatarsomere, ratio to dorsal metatibial spur: 1/2. Dorsal surface of tarsi glabrous, with punctures. Metatarsi, length of fi rst protarsomere subequal to second and third combined, ventral margin serrated and glabrous. Protibia with three teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow, claws asymmetrical, inner protarsal claw bifi d, apex of basal tooth of inner protarsal claw truncate.

A
. Lateral carina present. Second visible ventrite with row of setae in medial region. Apical visible ventrite without suture to apical tergite.
L . Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf present. Metatibia, widest at apex, distal spines groups disposed at two thirds of metatibial length. First metatarsomere, ratio to dorsal metatibial spur: 1/3. Dorsal surface of tarsi glabrous, without punctures. Metatarsi, length of fi rst protarsomere subequal to second and third combined, ventral margin serrated. Protibia with three teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow, claws asymmetrical, inner protarsal claw bifi d, apex of basal tooth of inner protarsal claw truncate.

A
. Lateral carina absent. Second visible ventrite without row of setae in medial region. Apical visible ventrite without suture to apical tergite.

A
. Lateral carina absent. Second visible ventrite without row of setae in medial region. Apical visible ventrite without suture to apical tergite.
L . Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf absent. Metatibia, widest at apex, distal spines groups disposed at half size of metatibial length. First metatarsomere, ratio to dorsal metatibial spur: 1/2. Dorsal surface of tarsi glabrous, without punctures. Metatarsi, length of fi rst protarsomere subequal to second and third combined, ventral margin serrated and setose. Protibia with three teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow, claws symmetrical, inner protarsal claw bifi d, apex of basal tooth of inner protarsal claw acute.

A
. Lateral carina absent. Second visible ventrite without row of setae in medial region. Apical visible ventrite without suture to apical tergite.
L . Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf present. Metatibia, widest at apex, distal spines groups disposed at two thirds of metatibial length. First metatarsomere, ratio to dorsal metatibial spur: 1/3. Dorsal surface of tarsi glabrous, without punctures. Metatarsi, ventral margin serrated and glabrous. Protibia with two teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow.

A
. Lateral carina present. Second visible ventrite without row of setae in medial region. Apical visible ventrite without suture to apical tergite.
L . Ratio of length of metepisternum / metacoxa: 1/0.86. Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf absent. Metatibia, widest at apex, ratio of width / length: 1/4.83, dorsal margin not carinated, ventral margin serrated, distal spines groups disposed at two thirds of metatibial length. First metatarsomere, ratio to dorsal metatibial spur 1/2. Dorsal surface of tarsi glabrous, with punctures. Metatarsi, length of fi rst protarsomere subequal to second and third combined, ventral margin serrated and setose. Protibia with three teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow, claws asymmetrical, inner protarsal claw bifi d, apex of basal tooth of inner protarsal claw truncate.

A
. Lateral carina present. Second visible ventrite with row of setae in medial region. Apical visible ventrite without suture to apical tergite.
L . Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf absent. Metatibia, widest at apex, ventral margin not serrated, distal spines groups disposed at two thirds of metatibial length. First metatarsomere, ratio to dorsal metatibial spur: 1/2. Dorsal surface of tarsi glabrous, without punctures. Metatarsi, length of fi rst protarsomere smaller than second and third combined, ventral margin glabrous. Protibia with three teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow, claws asymmetrical, inner protarsal claw bifi d, apex of basal tooth of inner protarsal claw truncate.

A
. Lateral carina present. Second visible ventrite without row of setae in medial region. Apical visible ventrite without suture to apical tergite.
A . Lateral carina absent. Second visible ventrite without row of setae in medial region. Apical visible ventrite without suture to apical tergite.
L . Ratio of length of metepisternum / metacoxa: 1/0.77. Metacoxa without longer lateral bristles, a laterally extended longitudinal shelf present. Metatibia, widest at apex, ratio of width / length: 1/3.34, dorsal margin carinated, ventral margin not serrated, distal spines groups disposed at two thirds of metatibial length. First metatarsomere, ratio to dorsal metatibial spur: 1/2. Dorsal surface of tarsi glabrous, without punctures. Metatarsi, length of fi rst protarsomere subequal to second and third combined, ventral margin serrated and glabrous. Protibia with three teeth. Protarsi, length of fi rst protarsomere subequal to second and third combined, second protarsomere narrow, claws symmetrical, inner protarsal claw bifi d, apex of basal tooth of inner protarsal claw acute.

Remarks
There is no diff erence between female type specimens of S. abcora and S. apolinarmaria except coloration, which is very variable. Therefore, we consider them synonymous.

A
. Lateral carina absent. Second visible ventrite without row of setae in medial region. Apical visible ventrite without suture to apical tergite.

Discussion
The current revision treated the types described by L.W. Saylor, of which six of 18 taxa are known only from females. This represents nearly 35% of the species, which makes a comprehensive taxonomic treatment diffi cult since generally all species of Sericini are distinguished with confi dence only through the examination of male genitalia. Although external morphology, including shape and surface structure of head, pronotum, and elytra, is relatively stable in South American Sericini compared to Old World Sericini lineages, the taxonomy of the species is complicated by the fact that sexual dimorphism is extreme in many species. Dimorphism is not only apparent in the shape of tarsi and pygidium, but also in body color and surface sheen; thus males and females of the same species are often not easily associated initially (e.g., Sayloria abcora).
We were able to identify Sayloria Frey, 1973 as a separate genus based on a comprehensive and comparative preliminary review of morphological characters within South American Sericini (Pacheco et al. in preparation). Exclusive hypothesized synapomorphies of Sayloria include mouthpart characters (e.g., the deeply excised anterior margin of the mentum) and the absence of a robust lateral carina on abdominal ventrites. Given the high degree of homoplasy in many morphological traits of Sericini that make a generic systematic very diffi cult (e.g., Ahrens 2006bAhrens , 2006cAhrens & Vogler 2008;Liu et al. 2015;Frings et al. 2020), results from comparative morphology will need to be supported by evidence from future molecular phylogenies. Fig. 7. Distribution of type localities of the South American Sericini species described by Saylor.