Deltocephalus, Burmeister, 1838

Webb, Michael D. & Viraktamath, Chandra A., 2009, 2163, Zootaxa 2163, pp. 1-64 : 10-12

The Deltocephalus group

The Deltocephalus group, in the Old World, comprises Deltocephalus (also New World, see Blocker et al., 1995), Recilia , Maiestas , Togacephalus , Inemadara , Insulanus and Inazuma . It is distinguished by the following combination of characters: pygofer without both processes or a posterior comb-like row of spines; subgenital plates separate with macrosetae arising laterally; style apical process short to moderately long, hook-like to digitate; connective and aedeagal shaft short to moderately long, the shaft less than 1½ times length of connective, cylindrical or trough-like, without lateral processes or if lateral processes present (subapically) then shorter than adjacent shaft apex ( trisuli Dash & Viraktamath and trispinosa Dash & Viraktamath , from India), with or without a spine-like apical extension but if present not shelf-like.

Many inconsistencies regarding the definition and status of the genera in the Deltocephalus group have arisen (due in large part), to differing interpretations of the structure of the aedeagus and as to whether the observed differences are at the generic or subgeneric level. In this context the recognised variation in the aedeagus is as follows (see also discussion under Maiestas below):

Group 1. Aedeagal shaft short and robust, strongly upturned distally without an apical extension, with a distinct apical gonopore ( Fig. 6h).

Group 2. Aedeagal shaft short and robust, weak to strongly upturned distally with a distinct apical extension and distinct apical gonopore ( Figs 4h, 5h).

Group 3. Aedeagal shaft elongate, gradually and weakly curved distally, with or without an apical extension that sometimes forms a ventral apical ridge; gonopore obscure ( Fig. 11h).

The following alternative options for the above groups, together with the names that have been applied to those groups, i.e. those names used prior to the current inclusion of Maiestas , are as follows:

Option 1. A single genus with two subgenera ( Ribaut, 1952, Knight, 1975 and Dash & Viraktamath, 1998), as follows: a Deltocephalus sensu lato

Subgenus 1. Deltocephalus sensu str . (Group 1)

Subgenus 2. Recilia sensu lato (Groups 2 and 3, including Recilia and the following synonyms:

Togacephalus , Inemadara , Inazuma and Insulanus).

Option 2. Two genera ( Kramer, 1962, Kwon & Lee, 1979, Day & Fletcher, 1994 and Kamitani, 1999;

Biedermann & Niedringhaus, 2004), as follows:

a Deltocephalus sensu str . (Group1)

b Recilia sensu lato (Groups 2 and 3, including Recilia and the following synonyms or subgenera: Togacephalus , Inemadara , Inazuma and Insulanus).

The following option is also possible but has not been used in the literature.

Option 3. Three genera as follows:

a Deltocephalus sensu str . (Group 1)

b Recilia s. str. (Group 2)

c Togocephalus sensu lato (Group 3, including Togacephalus and the following synonyms or subgenera: Inemadara , Inazuma and Insulanus).

With the inclusion of Maiestas into the Deltocephalus group its features of the aedeagus fall into those of Group 3 and unfortunately, as it is the older name, it takes priority over Recilia and Togacephalus in Options 1a Subgenus 2, 2b and 3c above. Therefore the revised Options 1–3, together with a fourth option, are as follows (revised parts in bold):

Option 1. A single genus with two subgenera as follows:

a. Deltocephalus sensu lato

Subgenus 1. Deltocephalus sensu str . (Group 1)

Subgenus 2. Maiestas sensu lato (Groups 2 and 3, including Maiestas and the following synonyms: Recilia , Togacephalus , Inemadara , Inazuma and Insulanus)

Option 2. Two genera as follows:

a. Deltocephalus sensu str . (Group 1)

b. Maiestas sensu lato (groups 2 and 3, including Maiestas and the following synonyms or subgenera: Recilia , Togacephalus , Inemadara , Inazuma and Insulanus)

Option 3. Two genera as follows:

a. Deltocephalus sensu lato, including Deltocephalus sensu str . and Recilia sensu str . as a subgenus or synonym: (Groups 1 & 2)

b. Maiestas (Group 3)

Option 4. Three genera as follows: a. Deltocephalus sensu str . (Group 1) b. Recilia sensu str . (Group 2) c. Maiestas sensu lato (Group 3, including Maiestas and the following synonyms or subgenera: Togacephalus , Inemadara , Inazuma and Insulanus)

Which of the above Options 1–4 is preferred is a matter of conjecture. However, for the present we consider it prudent to use Option 4, thereby retaining the well known genus Recilia for two species ( coronifer and raoi ), and transfering all other species formerly in Recilia or Deltocephalus (Recilia) to Maiestas .

Based on colour pattern and shape of the head, style and aedeagus, further sub-division of the new Maiestas group is possible, and some of this variability is reflected in the type species of Maiestas and the type species of its synonyms (see 4c above). For example, the type species of Maiestas ( M. illustris ), has a longer head than other species ( Fig. 11a), the type species of Togacephalus ( T. distincta ) and Inazuma ( I. dorsalis ), have distinctive style apical processes ( Figs 34f, 36f); the former has the aedeagus with an apical ventral ridge ( Fig. 34m) and the latter distinctive forewing markings ( Fig. 36o). In addition, some other notable variation is also present in some other species (see remarks under Maiestas below). However, until further work is done on the large assemblage of species in the new Maiestas group, we prefer not to give the above divisions formal group names.

With respect to some other stated differences between genera in the Deltocephalus group, we have found that, contrary to Linnavuori (1959: 129), the pygofer is dorsally sclerotised in both Deltocephalus and Recilia , and contrary to Kramer (1962: 259) the aedeagus in Deltocephalus can be without ( Fig. 6j) or with an apical notch, the lateral margin of the subgenital plate is slightly convex ( Fig. 6d) and in Recilia s. str. (as noted above), the gonopore is distinct ( Fig. 4i).