Diamella Shi & Liang, 2013

Shi, Hongliang, Zhou, Hongzhang & Liang, Hongbin, 2013, Taxonomic synopsis of the subtribe Physoderina (Coleoptera, Carabidae, Lebiini), with species revisions of eight genera, ZooKeys 284, pp. 1-129 : 38-40

Genus Diamella Shi & Liang nom. n.

Diamella Jedlička 1952: 81; Jedlička 1963: 307. Junior homonym of Diamella Gude, 1913 ( Hydrobiidae , Gastropoda). [Synonym]

Type-species:

Diamella kaszabi Jedlička, 1952, by monotypy.

Diagnosis.

Head and pronotum more or less pubescent; elytra with accessory setae at odd intervals or along striae, even intervals glabrous; vertex distinctly tumid, posterior supraorbital setae distant from eyes, insertions more or less pointed; internal sac of male genitalia with main flagellum extraordinarily thick, apical part of trumpet-form expansion strongly expanded.

In general appearance, this genus resembles Allocota , but the latter is different from Diamella in having: (1) head and pronotum always glabrous; (2) vertex less tumid and posterior supraorbital setae not distant from eyes; (3) lateral setae on pronotal margin absent; (4) males with terminal sternum bisetose on each side; (5) main flagellum of aedeagus finer.

Generic characters.

Dorsal side generally brownish to dark brown, elytra usually with metallic reflections; elytra unicolored. Head more or less pubescent, clypeus with some pubescence; eyes hemispherical, strongly prominent; tempora gradually narrowed behind eyes, longer than half length of eye; vertex distinctly tumid, posterior supraorbital setae distant from eyes, insertions more or less prominent, sometimes forming a horn-like hump. Antennae extended to basal one-sixth of elytra approximately; 1st antennomere slightly curved, 3rd slightly longer than 4th. Labrum with faint microsculpture, glabrous or with a few very fine short secondary setae, apex straight or emarginate; mandibles distinctly widened, outer margins rounded (as in Fig. 150 ), glabrous on outer scrobe, sometimes with a few short setae along dorsal ridge; terminal maxillary palpomeres fusiform in both sexes; terminal labial palpomeres strongly securiform, truncate apically in males, less widened in females; ligula with apex slightly projected, with four long setae; paraglossae membranous, not longer than ligula, narrow, adnate; mentum tooth simple, with two setae near base; submentum with two long setae; genae glabrous beneath eyes. Pronotum slightly wider than head, disc more or less pubescent; lateral margins with setae along full length, sometimes sparser at middle; primary mid-lateral setae present; pronotal base more or less lobed; lateral margins rounded in middle, sinuate before hind angles; hind angles sharp, rectangular or acute. Elytra wide, apex truncate, sutural angles not projected, outer angles completely rounded; anterior one third of sides slightly depressed or not, disc with or without a depression; odd intervals with accessory setae, even intervals glabrous; striae with or without setae; umbilical pores of 9th interval placed in one row; basal margination reaching to 3rd interval; basal pores present; primary setigerous pores indistinct among accessory ones, 3rd and 5th intervals with some larger pores; 7th and 8th intervals more or less tumid near apex. Ventral side with long and dense pubescence except proepisterna; males with apex of terminal sternum moderately emarginate, with 1one pair of setae; females with apex of terminal sternum straight or slightly curved, with two pairs of setae. Legs short; protibiae with cleaning spur well developed, distant from inner margin; tarsi widened, 4th tarsomere bifid, claws pectinate; males with adhesive hairs well developed (two whole rows) on 1st to 3rd protarsomeres, rudimentary (two rows, weakly present near apex) on 1st to 3rd mesotarsomeres. Male genitalia with median lobe of aedeagus not twisted; apical orifice opened apically; internal sac with main flagellum extraordinarily thick, apex nearly reaching to apical orifice, trumpet-form expansion strongly expanded; apical bursa absent; secondary flagellum short and indistinct. Female genitalia. Spermatheca very short, tubular, with distinct ring-sculpture, inserted on bursa copulatrix; spermathecal gland much longer than spermatheca, inserted distal to the middle of spermatheca; spermatheca indistinctly bent. Apical segment of ovipositor scimitar-shaped, curved to outer side; apical half setose; apex with elongate sclerotized extension.

Distribution

( Map 5 ). South China, Indo-China Peninsula, Malay Peninsula, the Philippines, Borneo, Sumatra, Java. Not discovered in South Asia or islands east of Wallace’s Line.

Etymology.

Jedlička proposed the name Diamella for this genus. Unfortunately, it was preoccupied by a genus of snails in Hydrobiidae . We propose a new name " Diamella " for this genus herein, respecting Jedlička’s notion, with only one letter changed. The gender of this genus name is feminine.

Monophyly and relationships.

The nearest allied genus to Diamella is unclear. From general appearance and setigerous pores on odd intervals, this genus may be related to Allocota . Detailed discussion is presented in the taxonomic comments below.

Monophyly of Diamella is suggested by the following apomorphic character states: (1) vertex distinctly tumid, posterior supraorbital setae distant from eyes, insertions more or less pointed; (2) males with one pair of setae on terminal sternum; (3) internal sac of aedeagus with main flagellum extraordinarily thick; (4) apical segment of ovipositor with apical extension sclerotized.

Taxonomic comments.

The first described species of this genus, Diamella cupreomicans ( Oberthür), has been placed in Calleida , Physodera and Allocota by different authors. Obviously, Diamella cupreomicans is much different from members of Calleida or Physodera . In general appearance, Diamella cupreomicans resembles some species of Allocota , but the concept of Allocota has never been clearly defined before the present work.

Among Physoderina, under the present system, Diamella cupreomicans could be more related to Allocota than any other genera both from external and genital characters ( Allocota also has the main flagellum slightly thick). But Diamella cupreomicans should be excluded from Allocota based on two important characters: (1) males with one pair of setae on terminal sternum; (2) apical segment of ovipositor long and with apical extension sclerotized.

The mysterious species Diamella kaszabi has never been mentioned after Jedlička (1952, 1963). So far, it is only known from the unique female holotype. We examined the holotype and confirmed that this species is congeneric with Diamella cupreomicans . The most important characters shared by them are tumid vertex and uneven pubescence on elytral intervals. We therefore redefine the concept of genus Diamella herein to include three species.

Key to species of Diamella nom. n.

1	Dorsal side uniform reddish brown, without metallic reflection; elytral base distinctly narrowed, hind wings reduced; elytral striae with punctures coarse; Taiwan	Diamella kaszabi ( Jedlička)
-	At least elytra with distinct metallic reflection; elytral base wide, shoulder distinct, hind wings well developed; elytral striae with punctures fine; species from other localities	2
2	Vertex strongly tumid, sides of the tumidity forming a pair of horn-like humps, posterior supraorbital setae inserted on them; front angles of pronotum strongly narrowed; elytra with striae distinct, some setae inserted along striae; widely distributed in southeast Asia, but not occurring in Philippines	Diamella cupreomicans ( Oberthür)
-	Vertex slightly tumid, not forming distinct horns, posterior supraorbital setae inserted on sides of the tumidity; front angles of pronotum widely rounded; elytra with striae barely sulcate, all setae on elytra inserted in middle of intervals; the Philippines	Diamella arrowi ( Jedlička)

Figures

Map 5. Known distribution of genus Diamella: ● Diamella cupreomicans (Oberthuer) ◆ Diamella kaszabi (Jedlicka) ★ Diamella arrowi (Jedlicka).

Figures 138 - 157. Characters of Physoderina. 138 - 139 Internal reproductive system of females, scale bars = 0.2 mm: 138 Dasiosoma quadraticolle sp. n., a paratype from Yunnan 139 Orionella lewisii (Bates), a specimen from Zhejiang. 140 - 142 Right protibia, ventral view, showing the reduction of cleaning spur, scale bars = 0.5 mm: 140 Allocota aurata (Bates) (cleaning spur absent) 141 Allocota bicolor sp. n. (cleaning spur fine) 142 Diamella cupreomicans (Oberthuer) (cleaning spur well developed). 143 - 146 Terminal sternum, showing the setae and male emargination, scale bars = 0.5 mm: 143 Paraphaea binotata (Dejean), male (deeply emarginate, one seta on each side) 144 Paraphaea binotata (Dejean) (straight, two setae on each side), female 145 Allocota aurata (Bates), male (moderately emarginate, two setae on each side) 146 Allocota aurata (Bates), female (straight, two setae on each side, right side unusually with an additional seta). 147 - 148 Umbilical series of 9 th interval, right elytron, scale bars = 0.5 mm: 147 Paraphaea binotata (Dejean) (umbilical series placed in one row) 148 Metallanchista laticollis sp. n. (umbilical series placed in two rows). 149 - 150 Head, showing the different shape of mandibles, scale bars = 0.5 mm: 149 Paraphaea formosana (Jedlicka) (mandibles moderately widen) 150 Allocota bicolor sp. n. (mandibles strongly widen). 151 - 153 Pronotum, showing the different length of setae on front angle, scale bars = 0.5 mm: 151 Allocota viridipennis Motschulsky, (setae short and fine) 152 Allocota cyanipennis Heller, (setae relative long) 153 Allocota bicolor sp. n., (setae very long). 154 - 155 Pronotum, showing the difference on lateral margin, scale bars = 0.5 mm: 154 Anchista fenestrata fenestrata (Schmidt-Goebel), (lateral margin slightly angulated in middle) 155 Paraphaea formosana (Jedlicka), (lateral margin completely rounded in middle). 156 - 157 Pronotal hind angle, showing the geographical variation in Allocota bicolor sp. n., scale bars = 0.2 mm: 156 Allocota bicolor sp. n., a specimen from Guangdong, (hind angle sharp) 157 Allocota bicolor sp. n., holotype from Yunnan, (hind angle slightly rounded).