Lucanus Scopoli, 1763

Zhan, Zhihong & Young, Daniel K., 2023, A taxonomic assessment and redefinition of the Lucanus fortunei species group in China (Coleoptera: Lucanidae: Lucaninae), Zoological Systematics 48 (4), pp. 279-360 : 284-285

Lucanus Scopoli, 1763

Lucanus Scopoli, 1763: 1 .

Hexaphyllus Mulsant, 1839: 119 .

Pseudolucanus Hope, 1845: 30 .

Key to species groups.

1. Mandibles significantly longer than length of head and pronotum ......................................................................................................2 Mandibles subequal in length to head and pronotum ...........................................................................................................................5

2. Prothoracic tibiae each bearing <5 spines, prothoracic tibiae bent anteriorly .................................... Lucanus fortunei species group Prothoracic tibiae each bearing>5 spines, prothoracic tibiae straight or sharply incurved anteriorly.................................................. 3

3. Ratio of mandibular length to length of head and pronotum greater than 1.5;>8 inner small mandibular teeth on each mandible; if mandibles with <8 inner small mandibular teeth, each mandible strongly incurved anteriorly............ Lucanus kraatzi species group Ratio of mandibular length to length of head and pronotum less than 1.5; each mandible with <8 inner mandibular teeth ................4

4. Mandibles straight along midlength and incurved distally, apical forks undeveloped, upper branches fork always subequal in length to fork of lower branche ........................................................................................................................ Lucanus parryi species group Mandibles straight along midlength but not strongly incurved distally, apical forks well developed, upper branches fork always longer than those of lower fork branche.......................................................................................................... Lucanus brivioi species group

5. Pronotum well-rounded anteriorly, not enlarged or forming acute angles................................... Lucanus fortunei species group (♀) Pronotum enlarged anteriorly............................................................................................................................................................... 6

6. Elytra concolorous with head and pronotum, surface with or without vestiture of setae .....................................................................7 Lateral aspects of elytra sometimes with yellow stripes or spots, surface smooth, without setae .......................................................... ....................................................................................................................................................... Lucanus parryi species group (♀)

7. Body slender, mandibular apices strongly incurved; pronotum square or polygon-shaped, elytral surface smooth............................... ...................................................................................................................................................... Lucanus brivioi species group (♀) Body stout, mandibular apices straight; pronotum trapezoidal, elytral surface usually covered with vestiture of yellowish setae ........ ..................................................................................................................................................... Lucanus kraatzi species group (♀)

As noted in the introduction, species group definitions for Lucanus are nebulous according to previous work (e.g., Huang & Chen, 2010). In this study, morphological characters were selected to identify not only the Lucanus fortunei group and related species groups, but also species group definitions across the entire genus.

The most informative characters for species group definitions of males include the following: 1) ratio of mandibular length and length of head and pronotum; 2) shape of the major inner mandibular tooth; 3) number and shape of small inner mandibular teeth (denticles); 4) protruding shape of the clypeolabrum; 5) angularity of the lateral cranial ridges; 6) number of mesothoracic tibial spines; 7) elytral color and vestiture; 8) shape of the aedeagus (basal piece).

The most informative characters for species group definitions of females include the following: 1) shape of apical mandibular teeth; 2) shape of the right inner mandibular tooth; 3) shape of the pronotum; 4) degree of enlargement of the prothoracic tibial apex; 5) shape of the preocular and postocular margins.

It should be noted that characters associated with female genitalia were not considered to be valuable in defining the species groups examined as part of this study. Preliminary investigations indicated that the shape of sclerotized caudal part of genitalia and spermatheca were unstable at the species level. Additionally, some female stag beetles in Lucanus are vulnerable, especially due to field collecting. During this study, the number of most Lucanus females collected and examined was limited to around 1–2 for each (sub)species. Some species such as L. datunensis was prohibited from any collecting.

Based on the characters listed above, the Chinese Lucanus can be divided into following groups: 1) Lucanus fortunei species group: 12 species / subspecies; 2) Lucanus brivioi species group (new species group): 14 species; 3) Lucanus kraatzi species group (new species group): 5 species; 4) Lucanus parryi species group (new species group): 1 species; 5) Lucanus laminifer species group: 6 species/subspecies; 6) Lucanus maculifemoratus species group: 10 species/subspecies; 7) Lucanus lunifer species group: 12 species/subspecies.

In this study, the Lucanus fortunei species group, together with its related groups ( Lucanus brivioi species group, Lucanus kraatzi species group, and Lucanus parryi species group) were examined and are discussed. A brief synopsis of taxonomic information for each species and subspecies are provided.