Trypoxylus dichotomus subsp. septentrionalis
Creators: name: Kim, Donguk
name: Hyun, Sangeun
name: Choi, Kwang Shik
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Trypoxylus
Trypoxylus dichotomus
Trypoxylus dichotomus septentrionalis (kôno, 1931)

description: Trypoxylus dichotomus septentrionalis (Kôno, 1931)
Materials
Type status: Other material. Occurrence: sex: gynandromorph; occurrenceID: BB0266CB-A621-5217-9808-8AFA3591AFA7; Taxon: genus: Trypoxylus; specificEpithet: dichotomus septentrionalis; scientificNameAuthorship: (Kôno, 1931); Location: country: South Korea; locality: Songyong Lee leg.; Event: eventDate: 30.XI.2019 (breed); Record Level: basisOfRecord: Preserved Specimen
Type status: Other material. Occurrence: sex: 1 male, 1 female; occurrenceID: D3195208-3391-57AF-A0E0-BCAD19B62715; Taxon: genus: Trypoxylus; specificEpithet: dichotomus septentrionalis; scientificNameAuthorship: (Kôno, 1931); Location: country: South Korea; stateProvince: Jeollanam-do; locality: Is. Jindo, Jukrim-ri, Imhoe-myeon, Jindo-gun; Event: eventDate: 4.VIII.2020; Record Level: basisOfRecord: Preserved Specimen
Type status: Other material. Occurrence: sex: 1 female; occurrenceID: 394BE149-33BB-5433-9E13-1FFA34CF3510; Taxon: genus: Trypoxylus; specificEpithet: dichotomus septentrionalis; scientificNameAuthorship: (Kôno, 1931); Location: country: South Korea; stateProvince: Jeju-do; locality: Is. Jejudo, Daepo-dong, Seogwipo-si; Event: eventDate: 29.VII.2018; Record Level: basisOfRecord: Preserved Specimen
Description
Morphology of the gynandromorph Trypoxylus dichotomus septentrionalis
The body exhibits a bilateral division of male and female phenotypes, with the left side displaying female characteristics and the right displaying male characteristics (Fig. 9). The head primarily exhibits female traits, but a subrectangular horn is present on the right side of the frons (Fig. 10). The pronotum resembles that of a male, with an incomplete horn on the left side and scattered punctures and pubescence appearing as spots on the surface (Fig. 10). The elytra display female characteristics (dense pale-yellow pubescence) on the left side, while the right side exhibits male characteristics (lacking dense pale-yellow pubescence) (Fig. 9). The legs exhibit a mixture of male and female traits. The protibiae on both sides display female characteristics (rather short and wide, with dense and wide punctures on the surface), but the claws are male-like. The mesotibiae and mesotarsi on both sides display female characteristics (rather short, with two external teeth on the outer margin of the mesotibia). The metatibia and metatarsus are asymmetrical, with the left side displaying female characteristics (a well-developed bidentate apex and a rather short tarsus), while the right side possesses both male (a rather narrow metatibia and a long metatarsus) and female characteristics (two external teeth on the outer margin of the metatibia). The femora overall exhibit male characteristics, except for the left profemur and left metafemur, which display female characteristics (rather wide, with the anterior margin of the profemur covered in dense yellow pubescence) (Fig. 9). The sternites exhibit asymmetry, with a narrow intersegmental space on the left and a broader one on the right (Fig. 11). The genitalia resemble a male aedeagus, but are asymmetrical between the left and right sides, abnormally developed and have paramere apices that are outwardly spread (Fig. 12). Additionally, eight eggs were found alongside the genitalia (Fig. 12).
Notes
In T. dichotomus septentrionalis, the primary male sexual characteristics include a well-developed horn on the head and pronotum, a relatively smooth pronotal surface and an elytral surface lacking dense pale-yellow pubescence. In the observed specimen, the body overall displayed a bilateral separation of male and female phenotypes (Figs 9, 10, 11), but the legs exhibited a complex mixture of male and female traits. Based on these male and female morphological distinctions, this specimen was classified as a gynandromorph.
description: Published as part of Kim, Donguk, Hyun, Sangeun & Choi, Kwang Shik, 2025, First report of an intersex individual of the click beetle Pectocera fortunei (Elateridae) and additional cases of gynandromorphism in Coleoptera (Lucanidae, Scarabaeidae), pp. e 144929 in Biodiversity Data Journal 13 on page e144929, DOI: 10.3897/BDJ.13.e144929