Callichrotus, Leschen & Chen & Harmer, 2024

Callichrotus gen. nov.

( Figs 1–2 View Fig View Fig )

Type species. Callichrotus gimmeli sp. nov., by present designation.

Diagnosis. The ovate, glabrous body form and antennal club of 2 antennomeres distinguish this genus from most Picrotini apart from Picrotus , which also has a broad lateral bead along the prothoracic carina with an abrupt inner margin with a furrow running parallel at the margin of the pronotal disc. It can be distinguished from Picrotus by its colouration, the widely separated antennal insertions with the frons between antennal insertions not strongly constricted and wider than length of antennal club, presence of a ridge on the vertex of the head, posterolateral angles of pronotum obtuse, prothoracic hypomeron separated from the pronotum by a suture, and abdominal ventrites 1 and 2 connate. The characters marked by an asterisk (*) in the description distinguish Callichrotus from Picrotus .

Description. Body form extremely short and stout, ovate, surfaces shining with extremely short, extremely sparse, inconspicuous, decumbent setae dorsally, erect or suberect setae totally absent; bicoloured. Head without tempora; vertex with ridge, temporal depression immediately anterior to ridge lacking; band of reticulate sculpture lacking. Frontoclypeus not projecting laterally anterior to antennal insertions; raised portion of frons between antennal insertions not strongly constricted, wider than length of antennal club. Transverse ridge above antennal insertions absent. Eye small, conical, not contacting antennal cavity; consisting of about 18 facets; interfacetal setae absent. Antenna inserted into large cavity on head; antennal club consisting of 2 antennomeres; antennomere 9 equal in width to antennomere 8 or almost imperceptibly wider. Mandible with apex bifid, subapical serrations present. Maxillary palpomere 4 subequal in length to 3; palpomere 4 conical but not subulate. Gena without antennal groove; genal spines broadly to narrowly rounded, right to obtuse. Gular sutures present, incomplete, not reaching occipital foramen. Pronotum not explanate, not constricted at base, equal in width to base of elytra, widest in basal half, distinctly transverse; anterior angles weakly to strongly projecting anteriorly (extending anterior to cervical foramen of prothorax), without a distinct platform; lateral carina present and complete, not bearing setigerous tubercles, lateral bead along the prothoracic carina broad, about as wide as antennal club, with an abrupt inner margin and furrow running parallel at the margin of the pronotal disc; disc without transverse basal impression extending across width of pronotum; paramedial carinae and paralateral plicae absent; posterolateral angles obtuse. Prothoracic hypomeron separated from pronotum by suture. Prosternum with anterior margin on same plane as disc; prosternal process with lateral marginal beads weakly present, parallel-sided, connected across apex, process without narrow longitudinal depression medially, process expanded apically, apex truncate and not crenulate, lacking setae; procoxal cavity with anterolateral notch. Scutellar shield clearly visible and transverse. Elytron lacking humeral tooth, lacking subbasal and subapical impressions; subapical gape present; punctation coarse, densely concentrated in scutellar region; vestiture originating in punctures, uniformly short and recumbent. Hind wing vestigial. Mesoventrite with mesoventrital cavity bowl-like, glabrous, flanked by sharp carinae. Mesanepisternal pit absent. Metaventrite with short, crenulate postcoxal lines; discrimen absent, posterior notch of metaventrite absent. Metendosternite with anterior tendons widely separated or absent. Tarsi 5-5- 5 in female, 5-5- 4 in male; tarsi compact, tarsomere 5 wider than preceding tarsomeres in lateral view; pro- and mesotarsomere 4 asetose; mesotarsomere 3 not lobed, with few setae; mesotarsomeres 1–3 of subequal to equal lengths with 1 longer than 2, 3 and 4 equal, 4 slightly shorter than 3, mesotarsomere 5 as wide as tarsomeres 1–4 combined. Abdominal ventrites 1–3 solidly fused with sutures nearly obliterated, with medial calli absent, lateral calli present or absent, intersegmental crenulations absent; ventrite 1 with intercoxal process broadly rounded, with postcoxal lines absent; medio-basal thickenings of ventrites 3–5 absent; apex of ventrite 5 with crenulations. Abdominal spiracles on segment VII with openings present and not larger in diameter than spiracle VI, texture smooth and atrium rounded and saclike. Aedeagus with tegminal strut absent, tegminal arms contiguous; parameres separate and articulated to phallobase with inner surface concave, fused parameres combined about 3 times longer than wide; apices multisetose; attachment point to phallobase not constricted, interparameral process present; basipenis 4 times longer than distipenis, without median carina; distipenis rectangular and elongate and about 2 times longer than wide, outer rims not crenulate, lateral lobes narrowly separated, symmetrical; internal sac with a single arrow-shaped plate. Etymology. The generic name is derived from a combination of the Latin prefix ‘ calli- ’, meaning beautiful, in reference to its striking colouration and ‘- chrotus ’, a genus ending used in one other cryptophagid. The gender is masculine.

Remarks. The species upon which this genus is based was originally considered an undescribed member of Picrotus by GIMMEL & LESCHEN (2022: fig. 69) mainly by the presence of a broad lateral pronotal bead shared by both genera, and not present elsewhere in the tribe.

Distribution. New Zealand.

Included species. Callichrotus gimmeli sp. nov.