Revue suisse de Zoologie 105 (3): 499-555; septembre 1998 A taxonomic revision ofthe family Oncopodidae I. New genera and new species ofGnomulus Thorell (Opiliones, Laniatores) Jochen MARTENS1 & PeterSCHWENDINGER2 1 Institut fürZoologie, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany. 2Institut fürZoologie und Limnologie, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria. A taxonomic revision of the family Oncopodidae I. New genera and new species of Gnomulus Thorell (Opiliones, Laniatores). - The genera Oncopus Thorell, 1876 and Gnomulus Thorell, 1890 are rediagnosed; Pelitnus Thorell, 1891 is synonymised with Gnomulus because of inter- mediate forms and identical penis structure. Seventeen species described under Pelitnus are transferred to Gnomulus; generic placement in six of them (known only from females or juveniles) is provisional. Taxonomic characters of Oncopodidae and relationships within the Oncopodidae and with other families are discussed. Pelitnus thorelli Schwendinger, 1992 is a primary homonym; the species unduely described under this name is G transferred to Gnomulus and renamed baharu Schwendinger nom. n. Three new genera and thirteen new species of mostly small oncopodid opilionids are described. Palaeoncopus gen. n., with P. gunung sp. n., P. kerdil sp. n., P. katik sp. n. from Sumatra possess a short, distad-directed, non-expandable glans penis, which is considered plesiomorphic. Bianton- copus gen. n., with B.fuscus sp. n. from the Philippines, has a similar but expandable glans. This character is regarded as apomorphic. Seven new G G species are placed in Gnomulus, i. e. crucifer sp. n., maculatus sp. n., G G coniceps sp. n., G. leyteensis sp. n., laruticus sp. n., G. asli sp. n. and G hirsutus sp. n. Their penis morphology, with a short proximad-directed glans, is typical for most Oncopodidae (also present in Oncopus) and is considered derived from the Palaeoncopus-type. Caenoncopus gen. n., including C. tenuis sp. n., C. affinis sp. n. and C. cuspidatus (Schwen- dinger) comb. n. (transferred from Oncopus) from Sumatra, has a glans penis comprising a strongly elongated, proximad-directed stylus wrapped in a membraneous collar. This structure appears highly apomorphic and is possibly an extreme modification of the penis type in Gnomulus and Oncopus. Intermediate states of reduction of glans sclerites and enlarge- ment of stylus are present in G. crucifer sp. n. and G. maculatus sp. n.. Manuscriptaccepted07.04.1998 500 J- MARTENS &P. SCHWENDINGER though rhey probably belong to a different evolutionary lineage. Four penis types are distinguished for the Oncopodidae; their evolution, generic significance and functional morphology are discussed. Key-words: Opiliones - Oncopodidae - Taxonomy - Penis morphology - Evolution - SE Asia. INTRODUCTION Since arevisionai study on the Oncopodidae ofthe Natural History Museum of Geneva (Schwendinger 1992), extensive and exceptionally rich new material has become available from the collections ofvarious colleagues and ourselves. Several of the small specimens in this material are particularly interesting, as they look similarto the enigmatic Oncopus cuspidatus Schwendinger. which has no genital-morpholo- gical resemblance to other Oncopodidae or even to other opilionids previously known. Afterclose examination, surprisingly they turned out to include not only close relatives ofO. cuspidatus but also otherforms with unexpectedpenis morphology. An account of this remarkable new material is given here; a thorough revision of the remaining taxa with new descriptions shall follow in subsequent papers. Although the newly available material contains plenty of exceptional forms, it nevertheless orig- inates from quite sporadic samplings and we believe that it only represents the tip of an iceberg. With more systematic sampling by sifting and soil extraction in all parts of Southeast Asia, a plethora of small and inconspicuous oncopodid taxa is expected to be discovered. Abbreviations and terms used in the text: CCD collection of C, Deeleman- Reinhold, Sparrenlaan; MAR collection ofJ. Martens, Mainz; MCSNG Museo Civico di Storia Naturale, Genova; MHNG Muséum d'histoire naturelle, Genève; SMF Senckenberg Museum. Frankfurt; ZMA Zoological Museum, University of Amster- dam; ZMTZoological Museum, University ofTurku. Body measurements referto the length of the dorsal scutum (i.e. distance between anterior margin of carapace and posterior margin of abdominal part ofdorsal scutum). Leg articles were measured on theirdorsal side, fromjoint tojoint. All measurements are given in mm. TAXONOMIC REMARKS Species concept We tried to find characters fordistinctions andrelationships between species in their penis morphology, but faced the problem of where to draw the boundaries in regard to the biospecies concept. Allopatric, morphologically similar and obviously closely related populations needed to be divided into "biospecies", without knowing whether or not reproductive isolation exists. As empirical data for such a grouping in Oncopodidae are non-existent (see Martens 1978 for Biantidae). we had to draw species boundaries in an arbitrar}- manner. Each seemingly allopatric population with NEWGENERA ANDSPECIES OFONCOPODIDAE 5Q] clear morphological distinctiveness is here regarded as a separate species. Due to the scattered and very localized nature of Oncopodidae collections (formerly caused by restricted accessability, today by habitat destruction), individual finds may show morphological distinctiveness, which does not correspond with species identity in the sense of the biospecies concept. In addition, geographical variation in Oncopodidae remains largely unclear. Therefore the species concept necessarily used here is close to the phylogenetical species concept, which clusters diagnosable populations into so- called "phylospecies" (Zink 1997). Traditional systemand generic limits Thorell (1876) described the subfamily Oncopodinae (under the family Cosmetoidae Koch) and later (1890) upgraded them to family rank. Within this group he successively distinguished three genera: Oncopus (Thorell, 1876), Gnomulus (Thorell, 1890) and Pelitnus (Thorell, 1891), which remained valid until the present day. The distinction between these genera is essentially based on tarsal formula (Oncopus 1-1-1-1, Gnomulus and Pelitnus 2-2-3-3) and presence {Pelitnus) or absence {Gnomulus) ofan oblique, strong, triangular eye tubercle (Thorell 1891: 93 - "Oculi basi tuberculi transversi fortis trianguli impositi."). The latter character, however, shows all transitions from aplane interocularareato aroundedhump and an acutely pointed prorect or erect eye tubercle in both nominal genera. The interocular area is sexually dimorphic in some species, with a low eye tubercle present in 9 ? and absent in SS. This was shown for G. lannaianus (sub Pelitnus lannaianus, Schwendinger 1992) and also occurs in G. sumatranus (in preparation). Therefore the traditional distinction between Gnomulus and Pelitnus cannot be maintained. Penis morphology in both genera (first illustrated for Gnomulus by Loman 1903: fig. 5f) is ofthe sametype. Adetailed accountofthis shall be given in ournextpaper. In contemporary taxonomy ofarthropods ó* genitalia are regarded to be among the most informative characters explaining relationships between taxa. Within the last decades this view became generally accepted and brought forth significant changes to high level systematics of opilionids. On the base of the genital morphology of SS, the family Fissiphallidae was established recently (Martens 1988) and the traditional suborders Cyphophthalmi and Palpatores were united to one suborder Cyphopal- patores (Martens 1980, 1986). Applying the same criteria to the family Onco- podidae, we placePelitnus in synonymy with Gnomulus, as was already suggested by Loman (1902: 183). Three new genera with penis morphology distinctly different from Gnomulus and Oncopus are establishedin the following. Definitionofthefamily Oncopodidae Oncopodid harvestmen are readily distinguishable by external characters, but most of these seem to be plesiomorphic for opilionids and are therefore not appro- priate to define the family. This holds true for the following characters in particular: 502 J- MARTENS & P. SCHWENDINGER extensive dorsal scutum (carapace and abdominal tergites fused); low number (1-3) of tarsal articles; restricted unidirectional articulation of the legs and pedipalps. The large, fused dorsal scutum clearly distinguishes the Oncopodidae from other Laniatores, but similar structures are also found in the Sironoidea and the Trogulidae, which are likewise slow-moving, soil-dwelling opilionids. All three taxa are addition- ally characterized by a low number oftarsal articles (up to 2 in Sironoidea S S up to , 4 in Trogulidae and up to 3 in Oncopodidae). Obviously the state ofboth characters is correlated with the mode of life of these cryptic animals. In Sironoidea large dorsal scutum and few tarsalia are considered plesiomorphic, whereas in the taxonomically distant Trogulidae the same most likely represent apomorphic reversals. Though oncopodids already possess clearly derived genital characters (e.g. hemolymph- pressure penis), theirlarge scutum and low number oftarsalia are difficultto evaluate. We assume that they representplesiomorphies. Only the following three character states are presently regarded as autapo- morphic ofthe Oncopodidae, defining the family as amonophyletic group: 1. Glans penis with lateral sclerites fused by an intermediate (median) plate (Figs 1, 134). In other families, symmetrical glans structures are not interconnected and can be moved independently from each other(Martens 1986). 2. Ovipositor laterally compressed, not dorso-ventrally flattened or circular in cross-section (Martens et al. 1981). This trait holds true not only for Oncopus (Martens et al. 1981), but was also found in Gnomulus, Biantoncopus gen. n., Palaeoncopus gen. n. and Caenoncopus gen. n. In the smallest representatives, however, ovipositorcross-sections generally tend tobe more roundish. 3. Cuticular appendages (paired or unpaired) on the carapace and the first abdominal tergite, respectively, form a small "bridge". This character is found only in Oncopodidae (Silhavy 1960). Regarding the scarcity of derived characters identified by now, the taxonomic position of the family Oncopodidae is again open to question. By no means can we presently trace character states that may warrant the status of a superfamily or a similarly high-ranking taxon for the Oncopodidae alone, as was suggested earlier (Silhavy 1960, Martens et al. 1981). At the present state of knowledge no sister group can be identified forthe Oncopodidae. DESCRIPTIONS Caenoncopus gen. n. Diagnosis: Distinguished by penis with dorso-ventrally depressed truncus, basally bilobed, subbasally not constricted; subapical glans large, composed of a strongly elongated, cylindrical stylus proximally enclosed in a membraneous collar; tip of stylus asymmetrical; glans folded proximad in resting position, lying in a shallow trench on the dorsal surface of the truncus. Body small without elevated scutal areas; interocular area developed as a round hump, not abruptly separated from NEWGENERA AND SPECIES OFONCOPODIDAE 503 Fig. 1 General scheme ofan oncopodid penis ofthe GnomuluslOncopus type; ventral (a) and lateral (b) view of distal part. - Apex of truncus (ap); two lateral sclerites (Is); median plate (mp); membraneous socket(ms); twomembraneous tubes (mt); subapical setae (ss); stylus (st). low thoracic area; chelicerae small, weak, with a pronounced dorso-distal and a small ventro-median hump on proximal article, no modifications on cheliceral hand; pedipalps with small ventral processes on proximal femurandtrochanter; ventral coxa II with anterio-proximal process; legs 3142, tarsal formula 1-1-2-2 or 1-1-3-3. Exter- nal sexual dimorphism in shape ofpalpal trochanterorabsent. Etymology: Greek: kainos = new, young; oncos = swelling;podos = foot; male gender. The Latinized name (correctly spelled "Caenooncopus", one "o" omitted to make it more euphonious) refers to the highly derived genital morphology of this genus andto its relationship with Oncopus. Type species: Oncopus cuspidatus Schwendinger. Species account and distribution: Three apparently allopatric species, i.e. C. cuspidatus comb, n., C. tenuis sp. n., C. affinis sp. n., are known from Sumatra. The lattertwo species occurin close proximity and are also closestrelatives. 504 J. MARTENS & P. SCHWENDINGER Fig. 2 Distribution of Oncopodidae in the Malay Peninsula and Sumatra. Only localities of species treated in this paper are shown. - a) Maxwell Hill (Gnomulus laruticus sp. n.); b) Chenderiang (G asli sp. n.); c) road to Genting Highlands (G. hirsutus sp. n.); d) Templer Park (G. hirsutus sp. n.); e) Ulu Gombak (G hirsutus sp. n.); f) Ketambe {Caenoncopus cuspidatus, Palaeoncopus kerdil sp. n.); g) Bukit Lawang (C. cuspidatus); h) Bohorok [Langkat Reserve] (C. cuspidatus, P. katik sp. n.); i) road Brastagi - Sibolangit [Deli Serdang] (C. cuspidatus); k) Panti (C affinis sp. n.); 1) road Lubuksikaping - Panti (C affinis sp. n.); m) Palopo Nature Reserve (C. tenuis sp. n.); n)5 kmSEofPayakumbuh(C. tenuissp. n.);o)Mt. Singgalang(P. gunungsp. n.). NEW GENERA AND SPECIES OFONCOPODIDAE 505 Fig. 3 Distribution ofOncopodidae in the Philippines. Only localities ofspecies treated in this paper are shown. - a) Sagada (Gnomulus maculatus sp. n.); b) Baguio, Cristal Cave (G coniceps sp. n.); c) Mt. Santo Thomas (G. crucifer sp. n.); d) Puerto Galera (G. maculatus sp. n.), doubtful record; e) Lake Danao, Leyte (Biantoncopusfuscus sp. n.); f) Visca N ofBaybay (B.fuscus sp. n., G. leyteensissp. n.). 506 J. MARTENS & P. SCHWENDINGER Fig. 4. Scanningelectron micrographs showingexternal characters ofOncopodidae species. - a) Palaeoncopus gumtng sp. n., left 9 palpal trochanter and base of femur, prolateral view; b) Caenoncopus tenuis sp. n.. tarsus and distal part of metatarsus IV; c-f) C. cuspidatus (Schwendinger), tarsus and distal part of metatarsus of leg II (c) and leg IV (d) , claws and aroliumon legIV ofjuvenile (e-f). . NEWGENERAANDSPECIES OFONCOPODIDAE 5Q7 Caenoncopus cuspidatus (Schwendinger) comb. n. Figs 4c-f, 5a-d, 6-8 OncopuscuspidatusSchwendinger, 1992: 190-192,figs. 67-80. Descriptionof 3 Types: SUMATRA, Northern Sumatra Province, Langkat, Bukit Lawang Nature Reserve, 180 m, S holotype (MHNG Sum-85/49). - Deli Serdang, north ofBrastagi, 1400 m, 3 paratype(MHNGSum-85/47); bothleg. B. Hauser, 8.-20.XI.1985. New material: SUMATRA, Aceh Province, Mt. Leuser National Park, Ketambe Research Station, 300-500 m, 23.-30.XI.1989, 4 3, 13 9; 800 m, 28.XI.1989, 1 9; all leg. D. Agosti, I. Lobi & D. Burckhardt (MCSNG, MHNG). - North SumatraProvince, Langkat, Bukit Lawang Nature Reserve, 11.-12.X.1990, 1 3, 1 9; leg. A. Riedel (MAR). - Bohorok. 7.VIII.Ï982, Ì 3, 1, 9, 13.XI.1983, 1 9, 30.XII.1993, 2 9; all leg. C. Deeleman-Reinhold&P. Deeleman (CCD). - Langkat, BukitLawang Nature Reserve, Bohorok river, 5.VII.1984, 1 3, 2 9; leg. J. Robert (MHNG). - Forest 7 km north ofBrastagi, 1500 m, 2.XII.1989, 1 3, 6 9; all leg. D. Agosti, I. Lobi & D. Burckhardt(MHNG). Diagnosis (extended): Relatively large species; scuta smooth, with charac- teristic pattern; palpal femur with ventro-basal process (Figs 7, 8); palpal trochanter sexually dimorphic, with distinct ventral process only in 9 9 (Fig. 7); tarsal formula 1-1-2-2; genital operculum with anterior hump (Fig. 6). Truncus penis with rounded apex drawn into an obtuse angle, bearing two widely separated rows of subapical setae on each side; stylus very long, almost reaching base of truncus, wrapped in a membraneous collar almost throughout its entire length; apex of stylus free, corkscrew-shaped (Fig 5a-d, Schwendinger 1992: figs 74-80). Remark: The small proximal tarsalia on the posterior legs, partly overlapped by the terminal edge of the metatarsus (Fig. 4d), were not recognized in the original description. Therefore C. cuspidatus was placed in the genus Oncopus. However, this placement was provisional. The author was aware of the uniqueness of the species, but decided not to establish a new genus because of the sparse material (2 3) available (Schwendinger 1992: 197). Variation: Measurements range: 3: body length 3.65-4.51 (x = 4.09, SD = 0.274), width 2.08-2.68 (x = 2.44, SD = 0.193), n = 10; 9 body length 3.59-4.39 (x = : 4.05. SD = 0.238), width 2.07-2.85 (x = 2.40, SD = 0.187), n = 27. Body size gradually decreases in between the three populations. Population: mean 3 body length (SD) mean 9 body length(SD): Ketambe 4.37 (0.089), n=4 4.24(0.090), n=14 BukitLawangandenv. 4.02 (0.056), n=4 3.98 (0.052), n=7 Brastagiandenvirons 3.67 (0.015), n= 2 3.68 (0.049), n=6 Distribution (Fig. 2): Known from the southern part of Aceh Province and from the northern part ofNorth Sumatra Province. The specimens examined originate from three separate areas: 1. Ketambe; 2. Bukit Lawang Reserve, Bohorok, Langkat; 3. Brastagi, Deli Serdang. Bionomics: The specimens were collected from the leaflitter ofa lowland rain forest and a montane rain forestwith various degrees ofdisturbance. Caenoncopus tenuis sp. n. Figs 4b, 9-17 Material: SUMATRA, West Sumatra Province 5 km southeast ofPayakumbuh. 600 m, 3 holotype (MHNG), 9<î,4 9 paratypes (MAR,,MCSNG, MHNG), 20.-21.XI.1989. - Palopo Nature Reserve, north of Bukittinggi, 900 m, 1 3 paratype (MHNG), 18.-20.XI.1989. All specimensleg. D. Agosti, I.Lobi & D. Burckhardt. 508 J. MARTENS & P. SCHWENDINGER Fig. 5 Scanning electron micrographs of penis of Caenoncopus cuspidatus (Schwendinger): total penis, dorsal (a) andlateral (b)view; apex ofglans,fronto-dorsal (c) anddorso-distal view (d). Figs 6-8 Caenoncopus cuspidatus (Schwendinger); 6 holotype (8), 9 (6, 7). - Genital operculum, latero-ventral view(6); leftpalp, retrolateral view (7, 8). - Scalelines0.5 mm. Etymology: Latin: tenuis=small, thin, delicate. Diagnosis: Closely related to C. cuspidatus, distinguished by smaller size and less extensive dark patches on dorsal and ventral scuta; distinct ventral process on palpal trochanter also present in ââ; tarsal formula 1-1-3-3; genital operculum without anterior hump. Truncus penis with broadly truncate apex carrying only one short row of subapical lateral setae on each side; stylus shorter, not reaching base of truncus; membraneous collar enclosing only basal half of stylus; apex of stylus different in shape (Figs 9-14). Description: 6 (holotype). Coloration: Body mostly light amber, except for: dark reticulation on carapace, dark margin and transverse bands on abdominal part of dorsal scutum (Fig. 17a), widely separated lateral pairs ofdark transverse patches on