Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 98. (Budapest 2006)

Makranczy, Gy.: Systematics and phylogenetic relationships of the genera in the Carpelimus group (Coleoptera: Staphylinidae: Oxytelinae)

sternite VIII and an apicomedial hook on the median lobe of aedeagus characterizing the Oxytelus group, and a pointed, well developed apical opening structure of the aedeagus in case of the Anotylus group. Within these major lineage groups, the genera are defined by characters appearing in several other genera as well, or by characters showing a lot of variation and intermediate character states among the known species. Based on these characters it is quite impossible to place all species unequivocally into genera and account for the yet undescribed or undiscovered species as well. To solve these problems and give more support to genus-group taxa, new characters were sought. The rhomboid fusion oftergite X One of the potential characters (in terms of generic definition) was an interesting modification of tergite X, most prominently displayed in the species originally included in Rimba BLACKWELDER, 1952 (Figs 127-128), but present also in a few other taxa. In these species the basal and lateral parts of tergite X split from the apical (rhomboid) part (Fig. 12) along 2 oblique lines and fuse to the lateral regions of tergites IX. When dissecting a specimen the apical (remaining) region usually breaks off easily from the sheath-like formation of tergites IX (Fig. 13). This feature is here first referred to as rhomboid fusion. Throughout the Oxytelus—Anotylus clade, and in some outside this lineage (Xerophygus, most notably) the apical part of tergite X has further modifications: serrate, oblique lines and apicolateral flaps usually bending ventrally from the main plane. I initially hoped that this character would support and better define Rimba. In the course of the investigation, however, it appeared that from the complete absence of this modification to a rather small rhomboid tergite X, many intermediate states are also present, although in a small percentage of species. In a group of Neotropical Anotylus, the oblique lines delimitating the rhomboid remnant are so close to the basal edge of tergite X that it is impossible to decide whether this is actually a fragmented tergite X or just a basally-narrowed, full segment. Apart from the aforementioned Xerophygus (Carpelimus group), the rhomboid fusion was also found in Oxytelus (Oxytelus group). It became clear that this character does not support Rimba, and has evolved several times in apparently distantly related species groups. Enlarged ventral struts on tergites IX The species formerly included in Oxytelopsis have the ventral struts of their tergites IX enlarged into a broad, rounded plate, almost as large as the main parts of these plates (Fig. 15). The occurrence of such a modification was studied within