Psammoecus delicatus Grouvelle, 1908

Yoshida 1, Takahiro, Karner, Michael & Hirowatari, Toshiya, 2018, A Revision of Taiwanese Species in the Genus Psammoecus Latreille (Coleoptera, Silvanidae), Zoological studies 57 (18), pp. 1-18 : 6-10

Psammoecus delicatus Grouvelle, 1908

( Figs. 1B , 5 and 6 )

Psammoecus delicatus Grouvelle, 1908: 477 . Type locality: Sri Lanka; Type examined. - Pal 1985: 21, fig. 6. - Sen Gupta and Pal 1996: 172, fig. 243.

Psammoecus x-notatus Grouvelle, 1912: 84 . Type locality: Taiwan: Akau (= Pingtung City, Pingtung County) for lectotype (3 paralectotypes were collected from Kosempo (= Jiaxian District, Kaohsiung City )); Type examined. syn. nov.

Psammoecus nitidior Grouvelle, 1919: 18 . Type locality: Indonesia (Java); Type examined. syn. nov.

Psammoecus raffrayi Grouvelle, 1919: 28 . Type locality: Singapore; Type examined. syn. nov.

Type series: Lectotype: male, “ Ceylan | Horn.”; “Type” [red label]; “Museum Paris | Collection | Grouvelle”; “ Psammoecus | delicatus | ty. | Grouv” [ Grouvelle’s hand] ( MNHN; studied by MK in 2015, here designated) . Paralectotypes: 4 females, “Sumatra | Palembang”; “ delicatus ” [printed label] ( MNHN; studied by MK in 2015, deposited in the collection of Grouvelle and Horn). Lectotype of P. nitidior syn. nov.: male, “Java”; “Type” [red label]; “ nitidior | ty. Grouv”. ( MNHN; studied by TY in 2017, here designated) . Paralectotypes of P. nitidior syn. nov.: 6 exs, same label data as the lectotype. ( MNHN; studied by TY in 2017, here designated). Lectotype of P. raffrayi syn. nov.: female, “ Singapore ”; “Type” [red label]; “ Raffrayi | ty. A. Grouv ”. ( MNHN; studied by TY in 2017, here designated) . Lectotype of P. x-notatus syn. nov.: male, “H. | Sauter. | Akau | Formosa | 1-10.12.07 [round label]”; “ Psammoechus [sic] | x-nigrum | type. Grouv.” [not Grouvelle’s hand]; “Museum Leiden. | Psammoe | cus | x notatus | Det: Grouv”; “type” [blue label]; “Cat. No | 5” ( RMNH; studied by MK in 2014, here designated) . Paralectotypes of P. x-notatus syn. nov.: 2 exs, same label data as the lectotype. ( MNHN; studied by TY in 2017, here designated); 1 female, “H. | Sauter. | Kosempo | Formosa | Jan. 08” [round label]; “ Psammoecus | x nigrum | G. Grouv” [Grouvelle’s hand]; “type”; “Museum Leiden. | Psammoecus | x notatus | Det: Grouv”; “type” [blue label]; “Type” [red label] ( RMNH; studied by MK in 2014, here designated); 1 male and 1 ex., same label data. ( MNHN; studied by TY in 2017, here designated).

Specimens examined: TAIWAN: [Miaoli County] 1 male (Catalog No. NMNS ENT 3235- 1443), Sanyi, 14-16-VI-1999, C. S. Lin & W. T. Yang leg., UV Light. ( NMNS). [Taichung City] 2 exs, Wufeng, Wufeng Disctrict, 24-IV-1992, Smetana leg. ( MHNG; studied by MK); 1 ex., Fengyuan, 22- IV-1990, Smetana leg. ( MHNG; studied by MK). [Nantou County] 1 male (Catalog No. NMNS ENT 1602-131), Chushan (= Zhushan Township), 8-9- XI-1993, C. S. Lin & W. T. Yang leg., UV Light. ( NMNS); 1 ex. (Catalog No. NMNS ENT 3513- 284), Lienhuachih, Yuchi Township, 6-VII-12- VIII-1998, C. S. Lin & W. T. Yang leg., Malaise Trap ( NMNS); 1 ex., NW Yuchi, Yuchi Township, 8-X-2009, Dányi & Lazányi leg. ( HNHM: studied by MK); 1 ex. (Catalog No. NMNS ENT 1582-328), Fenghuangku, Lugu Township, 20-22-IX-1993, C. S. Lin & M. L. Chan leg., UV Light ( NMNS); 1 male (Catalog No. 1337-5), Shih-tzu-tou, 6-IX-1987, I. C. Hsu leg., Sweeping Net. ( NMNS). [Chiayi County] 1 ex., Chuchi, Zhuqi Township, 20-VII-1966, H. Kamiya leg. ( KUM). [Kaohsiung City] 7 exs, Kosempo (= Jiaxian District), I-1908, H. Sauter leg. ( ZMHB, HNHM; studied by MK); 1 male and 4 exs, same label data. ( SDEI); 1 ex., Mt. Ta Yuen Shan near Liouguei, 5-VI-1989, K. Baba leg. ( KUM); 1 ex., Liu Kui (= Liouguei), 2-VIII-1989, K. Baba leg. ( KUM); 1 ex., same locality, 30-III-1986, K. Baba leg. ( EUMJ); 1 ex., Shanping Forest Recreation Area, near Liukuei, 19-21-XI-2009, Ronkay & Merkl leg. ( HNHM; studied by MK). [Taitung County] 8 exs, Pilam (= Taitung), II-1908, H. Sauter leg. ( HNHM; studied by MK). [Pingtung County] 11 exs, Akau (= Pingtung City), 1-10-XII-1907, H. Sauter leg. ( HNHM; studied by MK); 7 exs, same locality, 1-10-XII-1907, H. Sauter leg. ( ZMHB; studied by MK); 2 males and 8 exs, same locality, XII-1907, H. Sauter leg. ( SDEI); 1 ex. (Catalog No. NMNS ENT 6920-303), Nanjenshan, Manzhou Township, 1-19- IV-2009, M. L. Jeng & T. R. Chen leg., SLAM Trap. ( NMNS); 1 ex. (Catalog No. NMNS ENT 6920- 82), same locality & same period, M. L. Jeng & T. R. Chen leg., Flight Interception Trap. ( NMNS); 2 exs (Catalog No. NMNS ENT 6469-40 & 48), same locality, 21-VI-4-VII-2009, M. L. Jeng & T. R. Chen leg., Flight Interception Trap. ( NMNS); 1 male & 1 ex. (Catalog No. NMNS ENT 6469-486 & 503), same locality, 4-14-VII-2009, M. L. Jeng & T. R. Chen leg., Flight Interception Trap. ( NMNS); 1 ex. (Catalog No. NMNS ENT 6674-322), same locality, 27-IX-12-X-2009, M. L. Jeng & T. R. Chen leg., Flight Interception Trap. ( NMNS); 1 male (Catalog No. NMNS ENT 6632-57), Manchou (= Manzhou) Lite Chulaoshushan, 30-VIII-14-IX-2009, M. L. Jeng & T. R. Chen leg., Malaise Trap. ( NMNS); 1 ex. (Catalog No. NMNS ENT 6579-378), same locality, 12-26-IX-2009, M. L. Jeng & T. R. Chen leg., Malaise Trap. ( NMNS); 1 male (Catalog No. NMNS ENT 6525-85), Manchou (= Manzhou) Lite No: 169 Hsien Rd. 3.7 km, 19-IV-1-V-2009, M. L. Jeng & T. R. Chen leg., Flight Interception Trap. ( NMNS); 1 ex., Sichongxi, Checheng Township, 1-I-1986, K. Baba leg. ( EUMJ); 1 male. (Catalog No. NMNS ENT 6632-57), Manchou (= Manzhou) Lite Chulaoshushan, 30-X-14-IX-2009, M. L. Jeng & T. R. Chen leg., Malaise Trap. ( NMNS).

Diagnosis: This species differs from the other Taiwanese species by the very long and slender teeth on lateral margins of its pronotum, the pattern of these teeth, the pubescence composed of moderate and long setae on head, pronotum and elytra, and its large, strongly protruding eyes. Psammoecus delicatus is related to P. complexus Pal, 1985 , but can easily be distinguished by the different shape of the lateral pronotal teeth (see Pal 1985).

Description: Body length: 2.38-2.98 mm (n = 16).

Coloration: ( Figs. 1B and 5 ). Head and pronotum yellowish-brown. Elytra yellowish-brown with variable x-shaped blackish-brown maculae covering posterior 2/3 ( Fig. 5A and B ); posterior half of maculae in lighter color specimen obscure or absent; sometimes posterior 1/3 of elytra darkened ( Fig. 5C ). Antennae yellowish-brown basally, 7th to 10th antennomere sometimes darkened, 11th antennomere lighter colored, rarely also 10th antennomere lighter colored ( Fig. 5C ).

Head: ( Fig. 5 ). Wide, HW/HL 1.34-1.47; IE/HL 0.79-0.89. Temples gradually narrowed toward bases. Eyes large, well prominent. Dorsal surface punctation sparse and weak, pubescence composed of moderate and long setae. Antennae long; antennomeres with moderate and long, erect setae; distal portion of 7th to 10th and entire 11th antennomere covered with short pubescence, dense on 8th to 11th; approximate ratios of antennomere lengths of lectotype as follows: 3.0: 1.0: 1.3: 1.4: 1.4: 1.5: 1.2: 1.2: 1.2: 1.2: 2.4.

Pronotum: ( Fig. 5 ). Wide, point of greatest width variable, between anterior 1/3 and middle, distinctly narrowed toward base; lateral areas slightly flattened, PW/PL 1.32-1.42. Punctation on dorsal surface denser and slightly stronger than on vertex. Pubescence composed of numerous moderate and fewer long setae, long seta on each tooth and tubercle on anterior, lateral and posterior margins and anterior and posterior angles. Anterior angle with a few large tubercles; lateral margin with some dorso-laterally bent short to long teeth; posterior angle with a very small tooth and a small tubercle.

Elytra: ( Fig. 5 ). Oval, EW/BL 0.39-0.44. Rows of punctures slightly wider than interstices. Pubescence composed of many semi-erect moderate setae, most of interstices with rows of long erect setae, very long erect setae in a row along lateral margins, setae longer toward humeral swelling, anterior setae on small tubercles, with some long setae on lateral margin.

Male genitalia: ( Fig. 6 ). Spiculum gastrale ( Fig. 6A ) with short and thick strut, enlarged around base, diverging widely near middle; branches obscure and thin, connected by membrane; lateral sclerites elongate triangular, enlarged inwards near anterior 1/3. Parameres ( Fig. 6B ) small and stout, fused basally, rounded at apices, apex sometimes somewhat angular, dorsally with some small punctures around middle of inner margins, densely covered with setae of various length near apices, dorsally with some short, sparse setae near inner margins of apical 1/3, with a long apicolateral seta. Phallobase ( Fig. 6B ) long, subparallel, basal half of upper layer diverging, the branches widening distally, with membrane between bases of the branches, lower layer narrow, exposed around base. Penis ( Fig. 6C ) long, gradually narrowed toward apex, somewhat rounded at apex, with fine dense punctation around apex. Internal sac with very long and thin structure partly ringed around apex, with a pair of small spines near middle (sometimes absent), with a pair of large spines around base.

Distribution: Taiwan; India; Sri Lanka; Singapore; Indonesia.

Remarks: The external morphological characters as well as the male genital structures of P. x-notatus and P. nitidior type specimens show the typical morphology of P. delicatus . Hence, we conclude that these species are junior synonyms of P. delicatus . Although Grouvelle’s description of P. raffrayi suggests that at least two syntypes should be present, only one female specimen could be found and studied. Since P. delicatus is well characterized by its external morphological characters, we have no doubt that P. raffrayi is a junior synonym.

The unusual morphology of the spiculum gastrale is remarkable compared to that of other Psammoecus . This may indicate that this species belongs to a distinct species group. Studies of extensive material from the Oriental region revealed numerous closely related yet undescribed species.

Figures

Fig. 1. Psammoecus species of Taiwan, habitus. (A) P. taiwanensis sp. nov. (B) P. delicatus Grouvelle (C) P. harmandi Grouvelle (D) P. dentatus Grouvelle (E) P. trimaculatus Motschulsky (F) P. triguttatus Reitter (G) P. labyrinthicus Yoshida and Hirowatari (H) P. simonis Grouvelle (I) P. hiranoi Yoshida and Hirowatari. Scale bar = 1.0 mm.

Fig. 5. Habitus of Psammoecus spp. synonymized with Psammoecus delicatus Grouvelle. (A) Psammoecus x-notatus Grouvelle, paralectotype, male (B) Psammoecus nitidior Grouvelle, lectotype, male (C) Psammoecus raffrayi Grouvelle, lectotype, female. Scale bar = 1.0 mm.

Fig. 6. Male genital organs of Psammoecus delicatus Grouvelle, paralectotype of Psammoecus x-notatus Grouvelle. (A) spiculum gastrale (B) tegmen (C) penis. Scale bar = 0.2 mm.