Neochthebius granulosus (Satô)

Park, Sun-Jae & Ahn, Kee-Jeong, 2008, Redescription of the littoral genus and species of Neochthebius granulosus (Satô), and the first larval description for the genus (Coleoptera: Hydraenidae: Ochthebiinae), Journal of Natural History 42 (39 - 40), pp. 2501-2514 : 2506-2510

publication ID	https://doi.org/ 10.1080/00222930802354803
persistent identifier	https://treatment.plazi.org/id/03F4879A-FFA7-4512-1BE2-F9FCFF6F13D4
treatment provided by	Carolina
scientific name	Neochthebius granulosus (Satô)
status

Treatment

( Figures 1 View Figures 1–2 , 3–8 View Figures 3–8 , 9–10, 12–13, 15, 17–18, 19–20, 22, 24, and 26–36) Ochthebius (Cobalius) granulosus Satô, 1963: 129 .

Neochthebius granulosus: Perkins, 1980: 409 ; Jäch, 2004: 113.

Description

Adults. Length 1.4–1.6 mm. Body ( Figure 1 View Figures 1–2 ) almost unicolour, dark brown to dull black, antenna slightly lighter; about 2.8 times longer than wide; dorsum covered with some distinct white setae. Pronotum ( Figures 1 View Figures 1–2 and 19–20 View Figures 19–21 ) about 1.2 times wider than long; widest in front of middle; moderately narrowed apically, strongly narrowed basally. Elytra ( Figures 19–20 View Figures 19–21 ) about 1.5 times longer than wide. Abdomen ( Figure 24 View Figures 22–25 ) strongly imbricate; last abdominal segment of female with a row of 7–12 stout spines apically ( Figures 17–18 View Figures 15–18 ). Aedeagus as in Figures 7–8 View Figures 3–8 . Parameres as in Figures 7–8 View Figures 3–8 , apex with very short setae ventrally in lateral aspect.

Larvae (last instar). Length 2.5–2.7 mm. Body ( Figure 26 View Figure 26 ) pale, dark brown, antennae and urogomphi darker; elongate, parallel-sided. Head ( Figure 27 View Figures 27–31 ) subquadrate, lateral margins broadly rounded; widest at middle, 1.5 times wider than long; chaetotaxy as in Figure 27 View Figures 27–31 ; frontoclypeal suture indistinctly present; epicranial stem relatively short; V-shaped frontal arms long, reached nearly to antennae; neck absent. Clypeus ( Figure 27 View Figures 27–31 ) truncate, transverse, clypeolabral suture straight; three distinct setae (Cl1–Cl3) present on each side. Five stemmata present ( Figure 27 View Figures 27–31 ). Antenna ( Figure 31 View Figures 27–31 ) with three antennomeres; antennomere 1 widest; 2 sub-truncate, longest, 2.0 times longer than wide, 2.4 times longer than 3, four long setae present on apex; sensorium IIS1 present on apex of 2, as long as antennomere 3, IIS 2 minute; antennomere 3 short with four long and two short setae, 1.6 times longer than wide. Labrum ( Figure 28 View Figures 27–31 ) more or less semicircular; five labral marginal setae (Lm1–Lm5) present on each side, Lm2 furcated twice; two labral dorsal setae (Ld1–Ld2), one campaniform sensilla (C2). Mandibles ( Figure 29 View Figures 27–31 ) more or less symmetrical, triangular; base broad, apical half thin, moderately incurved; apex blunt; incisor edge serrate; prostheca fixed, hyaline, with serrate process at apex; mola well developed, tuberculate; with a distinct tooth above mola; two mandibula setae (M1–M2) and two campaniform sensillae (C1–C2) present. Maxilla as in Figure 30 View Figures 27–31 ; palpifer with crescent sclerite at base of maxillary palpus with one seta (Pf1); cardo triangular with one seta (Cdo1); stipes with three lateral setae (Stp1–Stp3) and one campaniform sensilla (C1); five lacinial setae (La1, La3–La6) present; maxillary palpi with three palpomeres, tapered apically; palpomere 1 about 0.8 times longer than wide, two campaniform sensillae (C1–C2) present; palpomere 2 sub-quadrate, 1.4 times longer than wide, two long setae (Pm1–Pm2) and one campaniform sensilla (C1) present; 3 slender, longest, 4.2 times longer than wide, apical third abruptly narrowed, sensorial digitiform appendage (SD) present. Labium indistinct; labial palpi with two palpomeres, small, indistinct; ligula pointed apically. Pronotum ( Figure 32 View Figures 32–34 ) with margins rounded; 1.7 times wider than long; widest at middle; four anterior (A1– A4), three lateral (L1–L3), four posterior (P1–P4), eight additional setae present on each side as in Figure 32 View Figures 32–34 ; five campaniform sensillae (C1–C5) present on each side. Mesonotum ( Figure 33 View Figures 32–34 ) rounded laterally, sharply narrowed posteriorly, moderately narrowed anteriorly; 2.0 times wider than long; widest near apex; four minute anterior setae (A1–A4), three lateral (L1–L3), four posterior (P1–P4), five additional setae present on each side as in Figure 33 View Figures 32–34 ; five campaniform sensillae present on each side. Metanotum ( Figure 34 View Figures 32–34 ) similar to mesonotum. Legs ( Figure 35 View Figures 35–36 ) long; all very similar in shape and distribution of setal patterns; trochanter large, triangular; femur transverse; tibia slender, narrowed apically, one stout seta present at inner middle dorsally, a small tooth present at inner margin of basal fourth with one pretarsal seta; tarsungulus with apex sharply pointed ventrally. Abdomen ( Figure 26 View Figure 26 ) with 10 segments; parallel-sided in basal half, slightly narrowed posteriorly; tergites I–VI expanded posteriorly and suddenly narrowed; VII parallel; VIII–IX slightly narrowed posteriorly; X strongly narrowed posteriorly, apical margin straight; two small anal hooks recurved ventrally. Urogomphi ( Figure 36 View Figures 35–36 ) triangular, two articled (URI–URII); apical fifth strongly narrowed and parallel; apex with a long seta ( AS), six setae (U1–U6) present. Abdominal sternites well sclerotized, form single plates. Respiratory system peripneustic and spiracles annular.

Materials examined

Adults. Ten specimens, Gugae, Gyeongbuk Prov., 6 VII 1991, K.-J. Ahn, ex rock crevice; seven specimens, Yongyeon, Gyeongnam Prov., 20 VII 1991, K.-J. Ahn, ex rock crevice; two specimens, Gabae-ri, Dongbu-myeon, Geoje Island , Gyeongnam Prov., J.-Y. Lyu and H.-J. Kim, 3 VII 1998, ex empty barnacles; one specimen, same as former except 30 VII 1999, K.-J. Ahn, ex on rocks; 12 specimens, same as former except 1 VII 2000, K.-J. Ahn, H.-J. Kim and M.-J. Jeon, ex barnacles; one specimen, same as former except 28 VI 2001, S.-J. Park and C.-W. Shin, ex under seaweeds; seven specimens, same as former except 30 VI 2001, S.-J. Park, ex inside of barnacles; two specimens, Is. Baekryeongdo, Incheon City Gyeonggi Prov., 7 VIII 2000, C.-W. Shin, ex on rocks; nine specimens, Geumgab beach, Imhoe-myeon, Jindo, Jeonnam Prov., 21 VIII 2001, S.-J. Park, ex on the barnacles; eight specimens, Myeongsasimri beach, Sinji-myeon, Wando, Jeonnam Prov., 23 VIII 2001, K.-J. Ahn and J.-H. Ahn; three specimens, Ilchulbong, Seongsan-eup, Namjeju-gun, Jeju Prov., 11 VI 2005, S.-I. Lee, S.-J. Park, K.-J. Ahn, M.-J. Jeon and D.-H. Lee, ex on rocks .

Larvae. Six specimens, Gabae-ri , Dongbu-myeon, Geoje Island, Gyeongnam Prov., Korea, 30 VI 1998, K.-J. Ahn and J.-H. Ahn .

Distribution

Korea and Japan.

Remarks

Neochthebius granulosus is very similar to N. vandykei in body shape and the structure of the aedeagus. However, it can be distinguished from the latter by the characters in the key. This species shows geographical variation: specimens from eastern costal regions of Korea and Japan have strongly imbricate antennomere 2 and maxillary palpomere 3 (Figures 10 and 13), pronotum with three distinct impressions on disk ( Figure 20 View Figures 19–21 ) and distal lobe of median lobe weakly sinuate in the lateral aspect. In contrast, specimens from southern costal regions and Jeju Island of Korea have weakly imbricate antennomere 2 and maxillary palpomere 3 (Figures 9 and 12), pronotum with indistinct impressions on disk ( Figure 19 View Figures 19–21 ), and distal lobe of median lobe strongly sinuate in the lateral aspect ( Figure 8 View Figures 3–8 ). The number of stout spines in the female last abdominal segment varies from seven to twelve.