Geoparnus rhinoceros, Kodada, Ján, Jäch, Manfred A., Jr, Fedor Č Iampor & Ová, Zuzana Č Iamporová- Za Ť Ovi Č, 2007

Kodada, Ján, Jäch, Manfred A., Jr, Fedor Č Iampor & Ová, Zuzana Č Iamporová- Za Ť Ovi Č, 2007, Geoparnus rhinoceros sp. nov., a new edaphic dryopid with unusual sexual dimorphism (Coleoptera: Dryopidae), Zootaxa 1481, pp. 59-68 : 60-68

Geoparnus rhinoceros sp. nov.

( Figs. 1 –20)

Type locality: forest floor debris in primary rain forest, close to a tributary of River Sut, about 25 km east of Kapit, Borneo, Sarawak, Malaysia.

Material examined: Holotype ɗ ( NMW): ” Sarawak (Borneo), ca 25 km E Kapit, 3. 1994, J. Kodada leg.”. Paratypes 25 ɗɗ, 24 ΨΨ ( NMW, CKB): with the same locality data as holotype; 4 ɗɗ, 5 ΨΨ ( CKB): " Sarawak (Borneo), Gunung Serapi, ca 19 km W Kuching, P. Bílek leg."; 2 ΨΨ ( CKB): " Sarawak (Borneo), Gunung Serapi, ca 19 km W Kuching, primary forest, III. 1994, J. Kodada leg."; 106 ɗɗ, 97 ΨΨ ( MHNG): "E Malaysia: Sarawak, 1994 Santubong, 32 km N Kuching, 0–100 m, 11.–15.V., no 1a, Burckhardt & Löbl leg."; 46 ɗɗ, 51 ΨΨ ( MHNG): "E- Malaysia: Sarawak, 1994, Gn. Gading, E slope, 50 m, 9 km E Lundu, 14.V., no 3a, Burckhardt & Löbl leg."; 8 ɗɗ, 6 ΨΨ ( SMNS): "Borneo: Sarawak, Belaga 14.–16. 3. 1990 leg. A. RIEDEL"; 5 ɗɗ, 2 ΨΨ ( SMNS): "Borneo: Sarawak, Kuching, Santubong 26. 3. 1990 A. RIEDEL".

Diagnosis (adult strage): Geoparnus rhinoceros is a medium sized species (body length 1.7–2.5 mm), unique among all known Dryopidae by the horn-like process on the head of the male. From Geoparnus setifer it differs furthermore in the following most obvious characters: (a) body form ovoid, strongly convex, moderately constricted between pronotum and elytra ( G. setifer is elongate-ovate, less convex); (b) flat-bottomed punctures on head and pronotum distinctly larger than a facet, shallowly impressed (in G. setifer these punctures are subequal to a diameter of a facet and deeply impressed); (c) scutellum concealed by elytra (in G. setifer scutellum small but well visible in dorsal view); (d) shape of male genitalia.

Members of Geoparnus are characterized by combination of the following characters: (a) conspicuous stiff setae with ridged surface and multifurcate apex; (b) short and compact body form and the antennal configuration.

Description: Habitus of male as in Fig. 1 . Body form ovoid, moderately constricted between pronotum and elytra, convex dorsally, very compact, strongly sclerotised; in males 1.54–1.92 (1.77±0.08) and in females 1.50–1.87 (1.72±0.08) times as long as wide (BL/EW); body length (BL): ɗɗ 1.73–2.40 mm (2.04±0.13), ΨΨ 1.76–2.50 mm (2.08±0.13). Colour black, clypeus, antennae, mouthparts and legs paler yellowish or reddishbrown. Immature specimens yellowish-brown.

Vestiture of body consists of several types of distinctly different setae: (a) short and longer hair-like setae ( Figs. 2, 4 , 12 ), and (b) conspicuous stiff shorter and longer setae with ridged surface and multifurcate apex ( Figs. 8, 9 ); all setae yellowish. Short hair-like setae adpressed, confined mainly to clypeus, pronotum, epipleura and ventral surface of thorax and abdomen, on elytra very scarce; longer hair-like setae concentrated mainly on anterolateral portion of clypeus; all hair-like setae arising from small sockets. Conspicuous stiff setae erect, arising either from large, flat-bottomed punctures ( Figs. 2, 4, 7, 8 , 12-14 ) on dorsal portion of head, pronotum, meso- and metaventrite and partly on ventrites, or from small sockets on elytra, legs, pedicell, central portion of ventrites and lateral parts of pronotum.

Head: Clypeus with fine punctures and fine reticulation; anterior margin produced dorsad forming a hornlike process in male ( Figs. 2, 3 ), arcuate and unproduced in female; surface around antennal insertion raised in male, nearly flat in female; frons and vertex with flat-bottomed large punctures, punctures ca. 3–4 times as wide as a diameter of a facet, punctures dense but distinctly separated from each other, interstices with fine punctures and short setae. Compound eyes moderately protruding from head outline, small, with few setae. Antennal insertion deep, scape short, pedicell enlarged, dorsally flat; antennal club moderately longer than scape and pedicell combined, nine-segmented.

FIGURES 21–22. 21) Box & Whisker plots showing the variability of body length of males at all localities; statistically significant differences between two morphological forms were detected. Plots show medians (solid horizontal line), means (dash lines), 25th and 75th percentiles (boxes), 10th and 90th percentiles (whisker extending from boxes), and 5th and 95th percentiles (outliers); 22) Box & Whisker plots showing the variability of body length/ elytral width ratio of males; no distinct morphological forms were detected.

Thorax: Pronotal disc strongly convex; PL: ɗɗ 0.60–0.79 mm (0.70±0.05), ΨΨ 0.50–0.76 mm (0.68±0.05); PW: ɗɗ 0.97–1.40 mm (1.13±0.08), ΨΨ 0.95–1.30 mm (1.15±0.07); lateral sides arcuate, crenulate; anterior margin of pronotum straight; anterior corners deflected, short and acute, moderately protruding; posterior margin bisinuate; posterior corners short; punctation similar to that on vertex but less dense. Hypomeron widest posteriorly, with scattered larger punctures ( Fig. 5 ); prosternum in front of coxae as long as prosternal process, strongly punctate ( Fig. 6 ); prosternal process longer than wide, lateral sides raised, apex subacute, surface densely punctate. Meso- and metaventrite very short ( Fig. 7 ), together shorter than prosternum, mesal portion deeply impressed, lateral portions with large punctures, interstices with fine reticulation. Elytra convex, without humeri; strongly declivitous laterally and posteriorly; lateral sides crenulate and visible in dorsal view to posterior margin of mesocoxa; apices moderately produced, acute; each elytron with nine rows of coarse, large, deeply impressed punctures, punctures about as coarse as those on pronotum but less sharply delimited and not flat-bottomed, often somewhat subquadrate; interstices on central portion usually less than half as wide as puncture diameter, laterally and posteriorly becoming narrower; intervals distinctly narrower than punctures in rows, feebly raised, with rows of stiff erect setae; anterior margin arcuate; scutellum concealed by elytra, inserted into cavity in sutural edge of each elytron. Epipleura anteriorly as wide as maximum width of profemur, narrowed posteriad, effaced near fifth ventrite, inflected at level of metacoxa, surface finely punctate. EL: ɗɗ 1.12–1.60 mm (1.33±0.11), ΨΨ 1.15–1.70 mm (1.39±0.11); EW: ɗɗ 0.95– 1.30 mm (1.16±0.09), ΨΨ 1.05–1.40 mm (1.21±0.09). Hind wings fully absent. Foreleg longest, moderately shorter than body; middle and hind legs slightly shorter; protibia feebly longer than profemur, straight or slightly bent and moderately thickened in both sexes ( Fig. 11 ); meso- and metatibia similar in form but shorter, with a small ventrodistal tooth in male; combined length of protarsomeres and claws moderately exceeds half length of protibia; claws of foreleg in male wider than in female.

Abdominal intercoxal process ( Fig. 12 ) moderately wider than prosternal process, apex subtruncate, lateral sides raised; first ventrite in middle slightly longer than second and third ventrite together; fourth ventrite about half as long as first one and nearly third as long as fifth ventrite; fifth ventrite more rounded and sides less declivous in male than in female ( Figs. 13, 14 ); surface of ventrites with large flat-bottomed punctures and micropunctures, setose. Eighth sternite with short median process in male (Fig. 19) and long in female (Fig. 20); ninth sternite narrow and long in male (Fig. 17).

Aedeagus (Figs. 15, 16): phallobasis robust, subcylindrical, moderately curved, 1.5–1.8 times as long as parameres, basally wider than apically (lateral view). Parameres moderately long, widest basally, gradually curved ventrad and gradually narrowed toward apices; apices subtruncate in lateral view. Penis distinctly shorter than parameres, widest basally, gradually narrowed apically; apex nearly acute (ventral view). Membranous ventral sac with fine longitudinal furrows; fibula absent. Ovipositor (Fig. 18) distinctly longer than abdomen; valvifer about 1.5–1.7 times as long as coxite; bursa copulatrix without sclerotised spinules.

Sexual dimorphism. Males with horn-like process on clypeus and tibial teeth, on average shorter, narrower and less convex than females (see BL, EW in Tabs. 1, 2).

Habitat. Specimens were collected by sifting ground debris containing leaf litter, decaying twigs, remnants of epiphytes, bark and other plant material accumulated mainly around large, living or dead trees. Most specimens were found in primary lowland forest.

Distribution. The species is known from several localities in central and southwestern Sarawak ( Fig. 23 ).

Etymology. Named in reference to the horn-like process on the male clypeus.

Variability. Analysis of variance showed significant differences among populations within all measured characters ( Tabs. 1, 2). The multiple comparison procedures revealed different results regarding sex.

Locality BL [mm] EL [mm] EW [mm] BL/EW PL [mm] PW [mm] PL/PW

Belaga 1.74–2.00 1.12–1.30 0.96–1.10 1.72–1.91 0.61–0.66 0.97–1.11 0.61–0.65

n = 9 1.852 ± 0.104 1.187 ± 0.077 1.034 ± 0.044 1.791 ± 0.061 0.659 ± 0.036 1.049 ± 0.043 0.628 ± 0.013

25 km E Kapit 1.76–2.07 1.12–1.30 1.00–1.14 1.73–1.90 0.64–0.76 0.97–1.12 0.62–0.72

n = 20 1.926 ± 0.075 1.236 ± 0.052 1.075 ± 0.041 1.792 ± 0.053 0.690 ± 0.029 1.051 ± 0.038 0.657 ± 0.023

Gunung Gading 1.95–2.40 1.30–1.60 1.10–1.30 1.54–1.92 0.60–0.75 1.05–1.40 0.48–0.64

n = 32 2.131 ± 0.105 1.445 ± 0.072 1.231 ± 0.061 1.733 ± 0.087 0.670 ± 0.045 1.180 ± 0.074 0.569 ± 0.041

Santubong 1.89–2.27 1.19–1.48 1.06–1.29 1.56–1.88 0.66–0.79 1.06–1.25 0.58–0.69

n = 31 2.072 ± 0.096 1.328 ± 0.069 1.168 ± 0.060 1.777 ± 0.087 0.744 ± 0.037 1.150 ± 0.054 0.648 ± 0.030

Gunung Serapi 1.99–2.19 1.28–1.43 1.11–1.17 1.80–1.88 0.71–0.76 1.08–1.17 0.66–0.67

n = 3 2.092 ± 0.102 1.344 ± 0.078 1.136 ± 0.030 1.840 ± 0.041 0.748 ± 0.029 1.131 ± 0.049 0.662 ± 0.005 F = 24.04 H = 61.17 H = 59.20 H = 13.11 H = 45.13 H = 46.79 H = 58.58

P <0.001 P <0.001 P <0.001 P = 0.011 P <0.001 P <0.001 P <0.001 In males pairwise multiple comparison tests of body length (BL), elytral length (EL) and maximum elytral width (EW) showed two morphological forms: (1) smaller and narrower males from central Sarawak (Belaga, Kapit env.) and (2) larger and wider males from southwestern Sarawak near Kuching (Gunung Gading, Santubong, Gunung Serapi). These groups are also evident from Box & Whisker plots of the data variability (BL—Fig. 21; plots of EL and EW not shown). Pairwise multiple analyses of maximum pronotal width (PW) and length (PL) suggest the same groups, with some exceptions: the conflicting comparisons always included males from Gunung Serapi, which is likely caused by insufficient data from this locality (n=3). Subsequent comparisons of the pooled data of both groups (using t-test) confirmed these two distinct morphological forms—significant differences were found within all tested metric characters (BL, EL, EW, PW with P<0.001, PL with P=0.008). Pairwise multiple analysis of BL/EW ratio showed no distinct groups (see also plot of the data variability Fig. 22). However the results of ANOVA ( Tab. 1) presented significant difference, this value of significance is the lowest within all characters tested (P=0.011). There was only one out of all ten pairwise comparisons of this character (population from Gunung Gading vs. Gunung Serapi) with significant difference. This suggests that ratio BL/EW vary rather slightly in males, and hence can be used as distinguishing character, but more data is needed to support this hypothesis. Concerning size of the clypeal horns, no disproportional development was observed as is known in many males of Scarabaeoidea (e.g. widely distributed palaearctic Oryctes nasicornis Linnaeus , Dynastinae ), i.e. in the largest males the size of the horn is proportionally similar to the size in the smallest males.

Locality BL [mm] EL [mm] EW [mm] BL/EW PL [mm] PW [mm] PL/PW

Belaga 1.91–2.04 1.25–1.33 1.09–1.18 1.68–1.85 0.66–0.71 0.98–1.15 0.62–0.70

n = 6 1.973 ± 0.045 1.284 ± 0.026 1.119 ± 0.032 1.764 ± 0.052 0.689 ± 0.023 1.056 ± 0.054 0.654 ± 0.032

25 km E Kapit 1.76–2.30 1.15–1.60 1.04–1.30 1.66–1.83 0.55–0.74 0.95–1.15 0.55–0.69

n = 22 1.996 ± 0.125 1.343 ± 0.106 1.147 ± 0.065 1.740 ± 0.049 0.640 ± 0.054 1.058 ± 0.054 0.605 ±0.045

Gunung Gading 1.95–2.50 1.35–1.70 1.20–1.40 1.50–1.79 0.50–0.75 1.15–1.30 0.44–0.61

n = 30 2.167 ± 0.111 1.487 ± 0.079 1.308 ± 0.053 1.657 ± 0.079 0.666 ± 0.046 1.190 ± 0.038 0.560 ± 0.033

Santubong 1.81–2.27 1.17–1.50 1.09–1.27 1.59–1.87 0.64–0.76 1.00–1.20 0.60–0.70

n = 30 2.117 ± 0.109 1.386 ± 0.079 1.192 ± 0.047 1.776 ± 0.057 0.731 ± 0.034 1.107 ± 0.046 0.661 ± 0.021

Gunung Serapi 1.79–2.09 1.15–1.35 1.06–1.24 1.66–1.78 0.64–0.74 0.98–1.12 0.64–0.66

n = 6 1.943 ± 0.110 1.259 ± 0.075 1.141 ± 0.069 1.703 ± 0.040 0.685 ± 0.038 1.056 ± 0.056 0.648 ± 0.008 F = 12.12 F = 17.65 H = 61.65 F = 15.06 H = 41.05 H = 58.73 H = 24.88

P <0.001 P <0.001 P <0.001 P <0.001 P <0.001 P <0.001 P <0.001 Analyses of variance of female metric characters revealed different results. In spite of that ANOVA showed significant differences in all tested characters ( Tab. 2), pairwise multiple comparisons and subsequent t-test did not propose the same groups (central Sarawak, soutwestern Sarawak) as analysis of male characters. These results suggest that females are more variable and the metric characters or proportions cannot be used to distinguish species. Higher intraspecific female variability was also supported by the pairwise test of the ratio BL/EW, where significant differences among populations were observed. Besides body proportions measurements of all tibiae were also analysed, however no well-defined groups were recognized.

Regarding the results of the analysis of metric characters in males, it is possible that specimens from southwestern and central Sarawak are discrete morphological forms, but concerning females these forms were not confirmed. It must also be noted, that all specimens in each of the populations were collected together from site of several square meters, and thus the differences could be due to idiosyncratic conditions of the sample rather than to a geographic cline (i.e. the particular conditions of the development of the specimens in the sample).

Except variations in metric characters, in a few specimens elytral punctures are irregularly arranged when comparing left and right elytron and punctures are partly confluent.

Figures

FIGURE 1. Habitus of Geoparnus rhinoceros sp. nov., male.

FIGURE 23. Known distribution of Geoparnus rhinoceros sp. nov. in Sarawak.

FIGURES 2 – 9. Geoparnus rhinoceros sp. nov., 2) male head, dorsal view; 3) male head, lateral view; 4) pronotum, dorsal view; 5) hypomeron and part of prosternum, ventral view; 6) prothorax, ventral view; 7) meso- and metathorax, ventral view; 8) detail of flat-bottomed punctures with stiff setae, ventral view; 9) detail of stiff seta, lateral view.

FIGURES 10 – 14. Geoparnus rhinoceros sp. nov.; 10) elytron, lateral view; 11) male protibia, lateral view; 12) abdomen in male, ventral view; 13) fifth ventrite in male, ventral view; 14) fifth ventrite in female, ventral view.