Siagotanyx Ashe, 2005

Ashe, James S., 2005, Three new genera and four new species of aleocharine staphylinids with unusually long mandibles from Australia (Coleoptera: Staphylinidae: Aleocharinae: Homalotini), Zootaxa 1002 (1), pp. 21-44 : 25-26

publication ID

https://doi.org/ 10.11646/zootaxa.1002.1.2

publication LSID

lsid:zoobank.org:pub:BF168D2B-1024-43FA-BA46-4E14BD5C7DE0

DOI

https://doi.org/10.5281/zenodo.5048606

persistent identifier

https://treatment.plazi.org/id/03E78796-FFE8-FFCF-316C-FB53FB0FCA45

treatment provided by

Felipe

scientific name

Siagotanyx Ashe
status

gen. nov.

Siagotanyx Ashe View in CoL , new genus

( Figs. 2 View FIGURE 2 , 14–24 View FIGURES 14–18 View FIGURES 19–24 )

Type Species. Siagotanyx rufa Ashe View in CoL , here designated.

Diagnosis. This genus can be easily recognized by the combination of: 4­4­5 tarsal segmentation; the extremely long mandibles with reduced prostheca, without modification to the internal base or molar area ( Fig. 16 View FIGURES 14–18 ); the transverse labrum with anterior margin emarginate medially, greatly reduced setation, but with one pair of antero­lateral setae extremely long and whip­like ( Fig. 14 View FIGURES 14–18 ); the distinctive labium ( Fig. 18 View FIGURES 14–18 ), with ligula deeply divided to near base into 2 narrow, widely separated, pointed lobes, 2 discal setae, bases of discal setae widely separated, and wide but poorly defined medial pseudopore field with numerous pseudopores; and relatively short antenna with antennomeres 4 subquadrate and 5–10 transverse ( Fig. 20 View FIGURES 19–24 ).

Description. Body generalized, slender, more­or­less parallel­sided, moderately flattened. Length 2.3–2.5 mm (known species). Head and prothorax very finely and uniformly covered with fine punctures and short, yellowish microsetae; elytra with moderatesized punctures and uniformly distributed yellowish microsetae; abdominal terga and sterna with longer and more prominent microsetae, uniformly distributed. Body without obvious microsculpture, glossy. Head subquadrate; eyes large, length in dorsal aspect about 0.7 times length of temples behind eye; temples broadly rounded behind eyes to base of head; neck absent; infraorbital carina present, complete, moderately well developed; antennal fossae very near lateral margins of clypeus, separated by lateral margins by less than 1/5 width of fossa. Antenna ( Fig. 20 View FIGURES 19–24 ) moderately short; known species with article 4 subquadrate, 5–10 transverse, 11 slightly shorter than 9 and 10 together.

Labrum ( Fig. 14 View FIGURES 14–18 ) transverse, separated from anterior margin of mentum by broad membranous area; anterior margin emarginate medially; setation reduced except one pair of antero­lateral setae very long and whip­like, oriented posteriorly in preserved specimens. Epipharynx as in Fig. 15 View FIGURES 14–18 . Mandibles ( Fig. 16 View FIGURES 14–18 ) with very long, curved and slender apices; right and left similar except right with very slight lobe in position of medial tooth; prostheca reduced with a few small teeth basally and a ciliate margin apically; internal base or molar area not modified into lobe. Maxilla ( Fig. 17 View FIGURES 14–18 ) similar to Eumecognathus except lacinia broader and spines and spinose setae of the inner face of lacinia more densely arranged; maxillary palpi 4­articled, similar to that of Eumecognathus . Labium as in Fig. 18 View FIGURES 14–18 ; ligula deeply divided to near base into 2 narrow, widely separated, pointed lobes, about 1/2 length of labial palpus 1; 2 discal setae, bases of discal setae widely separated; medial pseudopore field wide but poorly defined, without numerous pseudopores; lateral pseudopore fields each with setose pore, real pores, and about 13–16 pseudopores. Labial palpi 3­articled, first article subequal in length to next 2 together, article 2 and article 1 subequal in length, article 3 with 2 leaf­like sensory appendages apically. Mentum as in Fig. 18 View FIGURES 14–18 .

Pronotum transverse, 1.5 times as wide as long in known species; uniformly covered with short, yellowish microsetae, microsetae posteriorly directed in midline and posterolaterally to laterally directed on each side of midline, without conspicuous macrosetae; integument with very slight, weak microsculpture, surface glossy. Hypomera narrowly visible in lateral aspect. Elytra about 1.2 times longer than prothorax; postero­lateral margins sinuate. Meso­ and metasternum as in Fig. 21 View FIGURES 19–24 ; mesosternum faintly carinate medially at base; mesocoxal cavities fully margined behind; mesosternal process long, slender, pointed apically, extended beyond middle of mesocoxal cavities; metasternal process short, acutely rounded apically, not attaining mesosternal process, isthmus moderately long; known species with mesosternal process: isthmus: metasternal process in ratio of 1.7:0.7:0.9. Tarsal segmentation 4­4­5.

Abdomen parallel­sided, rounded apically. Known species with terga III–IV with moderate, V with slight and VI with inconspicuous transverse basal impressions; uniformly covered with moderately long microsetae. Surface without microsculpture, glossy.

Secondary sexual features: None obvious except males with anterior half of sternum VII with densely arranged micropores, and males with sternum VIII very slightly produced as a triangular lobe.

Etymology. The genus name is derived from the Greek noun “Siagon” (feminine) meaning “jaw” and the Greek verb “tanyo” meaning “stretch out” ( Brown 1956). It refers to the long, slender mandibles that characterize this genus. Gender: feminine.

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Staphylinidae

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