Eriotremex purpureipennis
Creators: name: Naven Kumar, R K
name: Sivalingam, Azhagu Madhavan
name: Alex, Arockia
name: Brahma, Neha
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Siricidae
Eriotremex
Eriotremex purpureipennis

description: Eriotremex purpureipennis (Westwood, 1874)
(Fig. 1)
Tremex purpureipennis Westwood, 1874: 117. Tremex insignis: Forsius 1933: 172. Not Smith (1859). Eriotremex purpureipennis: Benson, 1943: 44; Maa, 1949: 127; Maa, 1956: 92; Smith, 1978: 91; Smith, 2010: 434; Shinohara, 2022: 171. See Smith (1978) for more references.
Diagnostic characters. Female (based on one specimen examined). Length without ovipositor about 32 mm. Black with very faint bluish or purplish luster, shiny; antennal groove and apical part of apical ovipositor tinted with dark brown. Wings (Fig. 1C) black, iridescent with bluish or purplish luster. Head mostly covered with dense, well-separated punctures with smooth interspaces; most of gena nearly impunctate. Antenna (Fig. 1B) with 19 antennomeres; scape and pedicel punctate with smooth interspaces, flagellomeres impunctate and mat. Pronotum (Fig. 1A) with MPL about 0.65 times as long as OOCL, dorsal surface nearly smooth and glabrous, anterior margin and median part with sparse coarse warts and posterior margin densely microsculptured, mat and pilose. Forewing 1.42 times as long as ovipositor sheath. Abdomen (Fig. 1D) with tergum 1 finely coriaceous and mat, terga 2 and 3 shallowly coriaceous and weekly shiny, terga 4–7 smooth, shiny, with posterior half covered with minute, indistinct punctures, pilose; terga 8 and 9 smooth, shiny and, except for anterior margin, covered with minute, indistinct punctures, pilose. Precornal basin (Fig. 1E) about 0.82 times as long as wide, widest at slightly after middle; large median part fairly strongly convex, with distinct median longitudinal carina, surface punctate and pilose, and broad depressed lateral and anterior margins fairly smooth and impunctate. Ovipositor sheath about 3.42 times as long as apical sheath. Male Unknown.
Distribution. ɹ Malaysia: Malacca, North Borneo.
Material examined. ɹ MALAYSIA: 1 ˂, l Keningau, Sabah, N. Borneo, E. Malaysia, 25. IV. 1992 z (NSMT).
Host plant. ɹ Unknown.
Remarks. ɹ Eriotremex purpureipennis is a rare siricid with only two old published records, Westwood (1874) and Forsius (1933) (see Benson, 1943). Westwood (1874) did not give the number of specimens he had and simply noted l Malacca (Lorquin). In Mus. Jard. des Plantes, Paris (olim Coll. Sichel) z. Maa (1949) noted that the type was l lost (?) z without any comments. Smith (2010) noted l (type ˂, Hope Museum, Oxford University, U.K.) z, but this depository is not likely because Benson (1943) did not see the type of this species (l not seen z) whereas he examined the type of Tremex insignis Smith, 1858, deposited in the Oxford collection. Forsius (1933) noted the depository of the types of the new species he was describing but did not specify the depository of the non-typical material including the specimen of E. purpureipennis (his l Tremex insignis F. Sm. z) from North Borneo. I was not able to examine the material treated by Westwood (1874) and Forsius (1933).
Although Westwood (1874) did not give the number of specimens he examined, the specimen from North Borneo treated in this paper is probably the third specimen of this species ever recorded. Forsius` (1933) specimen was obtained in l Bettotan, near Sandakan z also in North Borneo. My specimen is from Keningau, which is about 200 km west of Sandakan.
The Keningau specimen runs to E. purpureipennis in the keys by Benson (1943), Maa (1949, 1956), Smith (2010) and Shinohara (2022) and agrees generally with the description by Westwood (1874). One disagreement is the number of antennomeres, which is 16 (l antennis 16-articulatis z) in Westwood`s material and 19 in my specimen. This is a large difference considering the ranges of intraspecific variations of four Japanese species of Eriotremex studied by Shinohara (2022); E. formosanus (Matsumura, 1912) has 19–21 antennomeres (female, n=14), E. makiharai Togashi, 2005, has 17–19 antennomeres (female, n=6), E. quadricinctus Shinohara, 2022, has 13 or 14 antennomeres (female, n=4) and E. ruficollis Shinohara, 2022, has 10 or 11 antennomeres (male, n=3). Eight Japanese species of the genus Tremex Jurine, 1807, have the similar ranges of variations, namely the largest intraspecific differences of three antennomeres (Shinohara, 2023). The variation range of this character in E. purpureipennis should be examined when more material becomes available.
Eriotremex purpureipennis closely resembles E. insignis but differs from it in the lack of paired yellow or whitish spots at the base of tergum 2 (Benson, 1943; Maa, 1949, 1956; Smith, 2010). The specimen of E. purpureipennis examined (Fig. 1) is different from the specimen of E. insignis shown in figs. 12–15 in Smith (2010) also in the convex and medially longitudinally carinate precornal basin (Fig. 1E) and the short and robust apical sheath (Fig. 1F); in E. insignis, the precornal basin is rather flattened and without a median carina (fig. 15 in Smith, 2010) and the apical sheath is long and slender (fig. 12 in Smith, 2010).
description: Published as part of Naven Kumar, R K, Sivalingam, Azhagu Madhavan, Alex, Arockia & Brahma, Neha, 2023, Rediscovery of a Malaysian Endemic Woodwasp, Eriotremex purpureipennis (Hymenoptera, Siricidae), pp. 43-46 in Bulletin of the National Museum of Nature and Science. Series A, Zoology 49 (1) on pages 44-45, DOI: 10.50826/bnmnszool.49.1_43, http://zenodo.org/record/13826542