ACANTHODERINI, Thomson, 1860

Santos-Silva, Antonio & Nascimento, Francisco E. De L., 2018, Synonymies, transferences, redescriptions and new species in Lamiinae (Coleoptera, Cerambycidae), Zootaxa 4462 (2), pp. 192-210 : 193-195

ACANTHODERINI

On the differences between Psapharochrus Thomson, 1864 , and Acanthoderes Audinet-Serville, 1835

Although it is beyond the scope of this work to provide a synopsis of the genera of Acanthoderini , we need to provide some comments on the differences among some genera in order to explain the allocation of two species currently in Psapharochrus .

Thomson (1864) included Psapharochrus Thomson, 1864 , Symperasmus Thomson, 1864, and Acanthoderes Audinet-Serville, 1835 in his “4 e Division—Acanthoderitae Verae”, characterized by him as follows (translated): “Frons wide; procoxal cavities rounded or slightly angulate sideward; femora clavate; tarsi short, protarsi in male widened and setose.” In the same work, he included Scythropopsis Thomson, 1864 in his “5 e Division— Onychoceritae”, defined as follows (translated): “Frons wide; antennae short, usually shorter than body, usually distinctly decreasing from antennomere IV; procoxal cavities “vel vix extus” [incomplete sentence], or angulate sideward; tibiae (especially protibiae) widened and nearly flattened; protarsi in male widened and setose.”

Additionally, Thomson (1864) separated his 4 th and 5 th divisions based on the granulation of the eyes (size of the ommatidia) (translated): “Eyes barely coarse, or finely granulate”, leading to Psapharochrus , Acanthoderes , and Symperasmus; “Eyes small, very finely granulate”, leading to Scythropopsis . Curiously, the position of the alternative of couplet is confused and makes no sense: Definition of the 4 th Division, first option of the dilemma, genera included in the 4 th Division, second option of the dilemma, definition of the 5 th Division, and genera included in the 5 th Division. Notwithstanding, the granulation of the eyes in Acanthoderes and Scythropopsis is identical (very fine) and not as in Psapharochrus and Symperasmus (coarser).

Lacordaire (1872) considered Symperasmus as a synonymy of Psapharochrus . Gemminger (1873) included Psapharochrus , Symperasmus and Scythropopsis as synonyms of Acanthoderes . Aurivillius (1923) listed Aegomorphus Haldeman, 1847 , Pardalisia Casey, 1913, Psapharochrus , Scythropopsis , and Symperasmus as subgenera of Acanthoderes . The species of Pardalisia, Scythropopsis and Symperasmus were listed by Aurivillius (1923) in A. ( Psapharochrus ), with the following commented (translated): “For the time being, it is impossible to distribute the species among these sub-genera, which have so far been insufficiently characterized.” Monné (1994b) and Monné & Giesbert (1994), followed Aurivillius (1923), but listed each species in the respective subgenus of Acanthoderes .

Tavakilian & Néouze (2013) described Scythropopsis boucheri from French Guiana. Accordingly, these authors considered Scythropopsis as a distinct genus, but did not provide any explanation. Monné (2018) still considered Scythropopsis as a subgenus of Acanthoderes .

As it is possible to see, the status and position of Acanthoderes , Psapharochrus , Symperasmus, and Scythropopsis has been chaotic, with authors synonymizing, revalidating, and changing the status without any explanation. Thus, to establish a point, we prefer to consider the later position in Monné (2018): Acanthoderes (Acanthoderes) ; A. ( Scythropopsis ); A. (Symperasmus); A. (Pardalisia); and Psapharochrus .

Apart from those controversial classifications, it was Lacordaire (1872) who provided the best feature to separate Psapharochrus ( Fig. 1 ) (including Symperasmus ( Fig. 5 ) as a synonym) from Acanthoderes (Acanthoderes) ( Fig. 2 ) and A. ( Scythropopsis ) ( Fig. 3 ). The former was included among the genera with eyes coarsely or sub-coarsely granulated, while the two latter were included among the genera with eyes finely granulated. Thomson (1864) also used this feature, but as seen above, Acanthoderes was incorrectly included among the genera with eyes not very finely granulated.

As the eyes in Symperasmus are not finely granulated, it makes no sense to include it as a subgenus of Acanthoderes . We prefer not to make any taxonomic change in this work regarding the placement of Symperasmus, but we believe that Lacordaire (1872) was right: Symperasmus is apparently a synonym of Psapharochrus .

The features pointed out by Casey (1913) separating Pardalisia (which has eyes very finely granulated ( Fig. 4 )) from Acanthoderes are not useful, and partially not true. For example, according to Casey (1913), the mesosternal process is “wholly devoid of tubercles” in Pardalisia, but according to Chemsak & Hovore (2002), the mesoventral process in Acanthoderes (Pardalisia) amplifrons Chemsak & Hovore, 2002 is “vaguely tuberculate at sides.” It is true that Chemsak & Hovore (2002) did not include their new species in subgenera, but they compared A. (P.) amplifrons with A. lacrymans (Thomson, 1865) and A. funeraria Bates, 1861 , suggesting the allocation. Also, according to Casey (1913), the elytra in Pardalisia are “together circularly rounded and perfectly entire at apex.” However, the elytral apex in A. (P.) amplifrons and A. (P.) lacrymans is truncate the latter included in A. (Pardalisia) by Monné & Hovore (1994) and Monné (1994b). It is likely that Pardalisia is a synonym of Acanthoderes , but a detailed study of the species currently in these genera (and subgenera) is necessary to confirm this synonymy.

At this point, only Acanthoderes (Acanthoderes) and Acanthoderes (Scythropopsis) need to be differentiated.

According to Lacordaire (1872), they can be separated as follows (translated):

1 Elytra entirely smooth........................................................................ Acanthoderes - Elytra with distinct carina.................................................................... Scythropopsis ”

Additionally, according to Lacordaire (1872), the lower eye lobes are large in Acanthoderes and small in Scythropopsis . This additional difference is true, at least in the type species of each genus. The elytral carina in some species currently placed in Acanthoderes (Acanthoderes) is absent or nearly so, and reaches from the basal quarter to beyond middle, or is distinct from base to outer apex. As there are species with small lower eye lobes and elytral carina complete from base to apex, as well as species with large lower eye lobes and elytral carina surpassing the middle of the elytra, it is not possible, for now, to establish the limits between these two genera/ subgenera. Accordingly, Scythropopsis is provisionally kept as a subgenus of Acanthoderes , although probably all species with lower eye lobes distinctly smaller than gena and elytral carina complete from base to outer apex belong to Scythropopsis (and it may be considered as a distinct genus), and all species with lower eye lobes longer or about as long as gena and elytra carina not reaching outer apex belong to Acanthoderes .

As Psapharochrus abstersus ( Bates, 1880) , and Psapharochrus pupillatus ( Bates, 1880) , have eyes very finely granulated, lower eye lobes distinctly shorter than gena, and elytral carina distinct from base to outer apex, they should be transferred to Acanthoderes (Scythropopsis) .

Acanthoderes (Scythropopsis) boucheri , apparently, has the eyes not finely granulated. If so, it cannot be a true Acanthoderes . As we do not have specimens of this species, we cannot correctly allocate it.

We understand that all these comments are not conclusive, but we believe that they are necessary, especially to draw attention to the need for a thorough review of Acanthoderes and Psapharochrus . After several problematic conclusions about these genera by previous authors, we prefer to not propose any synonymies and/or new ranks involving these genera without a detailed study of their species, even seeing that, evidently, there are several species that are incorrectly allocated. Furthermore, it will be necessary to verify other genera of Acanthoderini , as for example Aegomorphus Haldeman, 1847 , which belongs to this complex of genera.

In summary:

1. Symperasmus —probably a synonym of Psapharochrus , but, at least, it must be considered a subgenus of Psapharochrus .

2. Pardalisia —probably a synonym of Acanthoderes ;

3. Scythropopsis —probably a genus distinct from Acanthoderes ;

4. Eyes very finely granulated— Acanthoderes (Acanthoderes) ; A. (Pardalisia); A. ( Scythropopsis ).

5. Eyes coarsely or moderately coarsely granulated— Psapharochrus ; A. (Symperasmus).

Figures

FIGURES 1–5. Head showing granulation of eyes in the type species: 1, Psapharochrus cylindricus (Bates, 1861), male; 2, Acanthoderes (Acanthoderes) daviesii (Swederus, 1787), male; 3, Acanthoderes (Scythropopsis) albitarsis Laporte, 1840, male; 4, Acanthoderes (Pardalisia) funeraria Bates, 1861, female; 5, Acanthoderes (Symperasmus) thoracica White, 1855, male.