EUROPEAN ARACHNOLOGY 2003 LOGUNOV (D.V. & PENNEY D. eds.), pp. 67–74. © ARTHROPODA SELECTA (Special Issue No.1, 2004). ISSN 0136-006X (Proceedings of the 21st European Colloquium of Arachnology, St.-Petersburg, 4–9 August 2003)

A spiny harvestman (Arachnida: ) from the Upper Carboniferous of Missouri, USA

Øèïàñòûé ñåíîêîñåö (Arachnida: Opiliones) èç ïîçäíåãî êàðáîíà Ìèññóðè, ÑØÀ

J.A. DUNLOP

Institut für Systematische Zoologie, Museum für Naturkunde der Humboldt-Universität zu Berlin, Invaliden- strasse 43, D-10115 Berlin, Germany. email: [email protected]

ABSTRACT. A new fossil harvestman (Arachnida: Opiliones) is described from the Upper Carboniferous Coal Measures of western Missouri, USA. Echinopustulus samuelnelsoni gen. et sp.n. is tentatively assigned to the suborder and shares features with both trogulid and, less convincingly, ceratolasmatid opilionids. This fairly long-legged fossil is only known from the dorsal surface which exhibits a pustulate ornament and a remarkable, autapomorphic, morphology of two pairs of large opisthosomal spines: an anterior, paramedian pair emerging from a single, central tubercle and a posterior pair positioned more laterally. Like the French fossil Eotrogulus fayoli Thevenin, 1901, this new material may provide further evidence that the Dyspnoi clade extends back to at least the late Carboniferous (c. 300 Ma).

ÐÅÇÞÌÅ. Îïèñàí íîâûé èñêîïàåìûé ñåíîêîñåö (Arachnida: Opiliones) èç âåðõíåêàðáîíî- âûõ óãëåé çàïàäíîãî Ìèññóðè, ÑØÀ. Echinopustulus samuelnelsoni gen. et sp.n., êîòîðûé ïðåäâàðèòåëüíî îòíåñåí ê ïîäîòðÿäó Dyspnoi, íåñåò ïðèçíàêè êàê òðîãóëèä, òàê è â ìåíüøåé ñòåïåíè öåðàòîëÿñìèä. Ýòî îò÷åòëèâî äëèííîíîãîå èñêîïàåìîå èçâåñòíî òîëüêî ñ äîðçàëü- íîé ïîâåðõíîñòè, íà êîòîðîé èìååòñÿ ïóïûð÷àòûé îðíàìåíò è çàìåòíàÿ, àóòàïîðìîðôíàÿ, ñòðóêòóðà, ñîñòîÿùàÿ èç äâóõ ïàð êðóïíûõ îïèñòîìàëüíûõ øèïîâ: ïåðåäíåé, ïàðàìåäèàëü- íîé ïàðû, âûõîäÿùåé èç åäèíñòâåííîãî öåíòðàëüíîãî áóãîðêà, è çàäíåé ïàðû, ðàñïîëîæåí- íîé áîëåå ëàòåðàëüíî. Êàê è èñêîïàåìîå Eotrogulus fayoli Thevenin, 1901 èç Ôðàíöèè, íîâûé ìàòåðèàë îòîäâèãàåò íàõîäêè êëàäû Dyspnoi íàçàä, êàê ìèíèìóì äî ïîçäíåãî êàðáîíà (ïðèìåðíî 300 ìëí.).

KEY WORDS: fossil, Carboniferous, , harvestman, Dyspnoi, new species, USA. ÊËÞ×ÅÂÛÅ ÑËÎÂÀ: èñêîïàåìîå, êàðáîí, òàêñîíîìèÿ, ñåíîêîñåö, Dyspnoi, íîâûé âèä, ÑØÀ.

Introduction kevitch, 1913], and from the slightly older east Kirkton site in Scotland [Wood et al., 1985]. Fossil harvestmen (Arachnida: Opiliones) Restudy of the extinct order Kusta- are rare. The oldest examples date back to the rachnida from Mazon Creek has indicated that Early Devonian [Dunlop et al., 2003] and a these fossils are misidentified harvestmen [Beall, small number of Carboniferous harvestmen have 1986; Dunlop, 2004]. By contrast, the entire also been described. These come from the Coal Mesozoic has yielded only two incompletely Measures of Commentry in France [Thevenin, described specimens, while the Tertiary has a 1901] and Mazon Creek in the USA [Petrun- much more diverse and better known fauna 68 EUROPEAN ARACHNOLOGY 2003 including specimens in shales [Cokendolpher Germany. This incomplete and not very well & Cokendolpher, 1982] and inclusions in am- illustrated fossil is somewhat consistent with a ber [e.g., Cokendolpher & Poinar, 1998; Starê- living trogulid in overall shape, but this assign- ga, 2002; Dunlop & Giribet, 2003]. All four ment is difficult to confirm from the description suborders sensu Giribet et al. [2002] are repre- and again the status of the holotype is uncertain. sented in Tertiary amber and most of these In this paper a new fossil arachnid is de- fossils can be assigned to Recent genera. scribed from the Coal Measures of western The Upper Carboniferous harvestman fau- Missouri, USA. In overall appearance this spiny na currently consists of the rare Commentry and specimen is quite different from previously de- Mazon Creek forms which can now be divided scribed Carboniferous and clearly among three genera: Eotrogulus Thevenin, merits a new taxon. It is interpreted as the 1901, Nemastomoides Thevenin, 1901 and Kust- second example of an Upper Carboniferous arachne Scudder, 1890. The position of these dyspnoid harvestman; albeit of uncertain affin- fossils within Opiliones remains problematic. ities within the Dyspnoi clade. Both Eotrogulus and Nemastomoides have been included in the superfamily Troguloidea of the Material and methods suborder Dyspnoi. These two fossil genera were raised to new families by Petrunkevitch [1955]; The fossil was acquired from a private deal- albeit on questionable characters relating to the er (Charles Isbon) by Dr Elliot Nelson (St Lou- coxo-sternal region which should not be part of is, USA), who recognized its significance and the harvestman ground pattern. Restudy is re- made it available for study to the author. The quired to confirm their familial status and Dun- fossil was reportedly collected from private lop [in press] compared both Kustarachne and land in western Missouri, USA, but the exact Nemastomoides to living Eupnoi; the group locality could not be traced. It may come from which includes the most common ‘daddy-long- near the town of Windsor. However, a number legs’ type of harvestmen. of sites in western Missouri yield Coal Measure Dyspnoi are fairly abundant and widespread fossils similar to the famous Braidwood section today across the northern hemisphere, although of the Mazon Creek locality [B. Stinchcomb, they do tend to be predominantly soil pers. comm.] and in general these Missouri coal and are thus more cryptic than the more familiar deposits are not as extensive or as well re- Eupnoi. Modern-looking Dyspnoi assignable to searched as those of Illinois, which include the living genus have long been Mazon Creek. The Missouri fossils are pre- known from Tertiary amber [see e.g., Petrun- served in a similar way to Mazon Creek materi- kevitch, 1955], but the only reliable Palaeozoic al as impressions in clay-ironstone concretions. dyspnoid harvestman is the French fossil The sediments yielding the Missouri concre- Eotrogulus from the Coal Measures of Com- tions belong to the Pleasanton Group, which is mentry. From its description in the literature dated to upper Middle Pennsylvanian; equiva- Eotrogulus looks superficially like a member of lent to the Upper Carboniferous in European the trogulid clade, with a somewhat elongate, stratigraphy. A summary of the geological set- lozenge-shaped body in which the opisthosoma ting of this region can be found in Howe [1982]. is broadly joined to a subtriangular carapace. The fossils were studied under a stereomicro- The legs are quite long and slender, but nowhere scope with a camera lucida attachment used to near as extreme as in some phalangiid harvest- prepare the drawings. A fine needle was used to men. Eotrogulus was raised to a new, monotyp- prepare the anterior part of the carapace and also to ic family and potentially represents the oldest excavate the soft sediment infill from the spines on the back of the opisthosoma. Other Upper Carbonif- record of both Troguloidea and Dyspnoi. Un- erous harvestmen from Mazon Creek were obtained fortunately the status of the holotype is uncer- from the United States National Museum (USNM) tain. The only other fossil trogulid described in and the Peabody Museum, Yale (YPM). Of the non- the literature is Trogulus longipes Haupt, 1956 amber dyspnoid harvestmen, Eotrogulus fayoli Thev- from the Eocene ‘Braunkohl’ of Geiseltal in enin, 1901 was reported from the Museum National J.A. Dunlop. A new Carboniferous harvestman 69

Figs 1–2. Echinopustulus samuelnelsoni gen. et sp.n., a new spiny harvestman from the Upper Carboniferous Coal Measures of western Missouri, USA. 1 — part; 2 — counterpart. Scale: 2 mm. Ðèñ. 1–2. Echinopustulus samuelnelsoni gen. et sp.n., íîâûé øèïàñòûé ñåíîêîñåö èç âåðõíåêàðáîíîâûõ óãëåé çàïàäíîãî Ìèññóðè, ÑØÀ. 1 — îñíîâíàÿ ÷àñòü; 2 — îáðàòíûé îòïå÷àòîê. Ìàñøòàá: 2 ìì. 70 EUROPEAN ARACHNOLOGY 2003 d’Histoire Naturelle (MNHN) in Paris, but could Prosoma not be traced in the collections during a recent The carapace is subtriangular, but the ante- search [A. Rage, pers. comm.]. Similarly, the type of rior tip is, unfortunately, not preserved. Exca- Trogulus longipes should be in the Gieseltal Muse- um in Halle, Germany, but could not be traced [M. vation of the anterior end failed to reveal struc- Hellmund, pers. comm.]. The fossil material was tures such as eyes (which remain equivocal) or, also compared to extant harvestmen in the zoological for example, the characteristic bilobed ‘hood’ collections of the Museum für Naturkunde, Berlin. seen in modern trogulid harvestmen. The cara- pace expresses a weak division or sulcus to- Results and discussion wards its posterior end. Although not a separate sclerite, this corresponds to the metapeltidium or last thoracic tergite sensu Giribet et al. [1999: Morphological interpretation character 21]. The median band and ornament The fossil (Figs 1–4) is preserved in a nod- here have been noted above. The mouthparts ule as a part and counterpart. Both show the and pedipalps are not preserved. The leg series dorsal surface of the , respectively, in is incomplete and only the proximal podomeres positive and negative relief. The latter pre- are preserved. They give the impression of serves more details of the morphology and or- slender, rather gracile legs in which the femora namentation. Descriptions are of the appear- widen distally; see the leg 1 femur in particular. ance of the animal ‘in life’. In overview, this is The trochanters are quite well preserved as a small to medium sized arachnid, c. 9 mm long, short, somewhat globular podomeres which in which the prosoma and opisthosoma are some- widen distally. what compact and broadly joined together via a procurved sulcus, with little tagmosis between Opisthosoma them. The limb series is incomplete, but is The opisthosoma is the best preserved re- suggestive of long, fairly slender legs. Togeth- gion. It is oval, about one and a half times as er, these features strongly imply that this fossil long as wide. It seems to have become splayed is a harvestman, although (as with existing Car- out on one side with an irregular margin. This boniferous harvestmen) unequivocal autapomor- may be a taphonomic effect of compression. phies of the order relating to the genitalia and Generally, the fossil retains much of the origi- repugnatorial glands cannot be resolved. nal three-dimensionality. The dorsal side of the opisthosoma is dome-shaped and highly vault- Ornament ed (Figs 1, 3); considerably more so than the The general dorsal body surface of both the carapace. An important feature of note is the carapace and opisthosoma is covered with a apparent lack of clear tergal divisions along the distinct ornament of fairly dense, tiny pustules. entire length of the opisthosoma. In the scheme In places their preservation is patchy and they of Giribet et al. [2002: character 115] this de- are more apparent on the counterpart (Fig. 4), gree of tergite fusion approaches an apomor- especially under low angle lighting. They seem phic character state which has been termed the to fade out towards the margins of the carapace ‘scutum magnum’. It should be noted that vary- and they tend to form ring-like patterns around ing degrees of opisthosomal tergite fusion have the median tubercle for the anterior spines (see been acquired, probably independently, in a below). This pustulate ornament is absent from number of modern harvestman lineages. a slightly raised, but weakly defined median The new fossil preserves another interesting band, about 0.5 mm wide, which extends from apomorphic feature. The part expresses three the middle of the carapace down along the raised tubercles on the back of the opisthosoma length of the opisthosoma where it is interrupt- (Figs 1, 3). The median tubercle occupies a ed only by the anterior spine tubercle. The legs central position on the opisthosoma where it are not well enough preserved to resolve wheth- bisects the median band along the back of the er the pustulate ornament continues here too. animal. This tubercle bears the outline impres- J.A. Dunlop. A new Carboniferous harvestman 71

Figs 3–4. Camera lucida drawings of the specimens shown in Figs 1–2. Abbreviations: at = anterior spine-bearing tubercle; cp = carapace; fe = femur; mb = median band; op = opisthosoma; pt = posterior spine-bearing tubercle; su = sulcus; th = thoracic tergite (or metapeltidium); tr = trochanter. Legs numbered from 1–4. Scale: 2 mm. Ðèñ. 3–4. Ïåðåðèñîâêà ýêçåìïëÿðà, ïîêàçàííîãî íà Ðèñ. 1–2, ñ ïîìîùüþ ðèñîâàëüíîãî àïïàðàòà. Ñîêðàùå- íèÿ: at = ïåðåäíèé áóãîðîê, íåñóùèé øèï; cp = êàðàïàêñ; fe = áåäðî; mb = ìåäèàëüíàÿ ïîëîñà; op = îïèñòîñîìà; pt = çàäíèé áóãîðîê; íåñóùèé øèï; su = ñóëüêóñ; th = òîðàêàëüíûé òåðãèò (èëè ìåòàïåëüòèäèóì); tr = òðîõàíòåð. Íîãè ïðîíóìåðîâàíû îò 1 äî 4. Ìàñøòàá: 2 ìì. 72 EUROPEAN ARACHNOLOGY 2003

Fig. 5. Sketch reconstruction of the appearance in life of Echinopustulus samuelnelsoni. The anterior end of the carapace is unknown and not reconstructed here. Ðèñ. 5. Ñõåìàòè÷åñêàÿ ðåêîíñòðóêöèÿ âíåøíåãî âèäà Echinopustulus samuelnelsoni. Ïåðåäíÿÿ ÷àñòü êàðàïàêñà íå èçâåñòíà è ïîýòîìó íå ðåêîíñòðóèðîâàíà. sions of the bases of two conical, paramedian which are suggestive of particular living taxa projections. The other two tubercles are poste- (see below). The absence of eyes, pedipalps, rolateral on the opisthosoma and again each is and the entire leg series are a hindrance to clearly the base of a larger, projecting structure. resolving its affinities, while characters like The counterpart (Figs 2, 4) confirms that each pustulate cuticle occur in representatives of all of these four bases bore a large spine or thorn. major harvestman clades [Roewer, 1923; Mar- Excavation of the matrix infilling the spines tens, 1978]. It is conceivable that there were revealed that these tapering structures extend stem group Palaeozoic harvestmen which dif- quite deeply into the counterpart and would fered substantially from living forms and which have been prominent projections on the back of are not assignable to existing clades. Neverthe- the animal in life. The median pair originating less, the modern crown groups of some subor- from a single tubercle essentially point upwards ders can be excluded. while the posterolateral pair project upwards The apparent absence of opisthosomal terg- and backwards. They are clearly defensive ad- ites is similar to the situation in the basal cytho- aptations increasing the handling time of the phthalmid harvestmen. However, unlike the animal to potential predators. Spines of various Missouri fossil, cyphophthalmids do not show lengths and orientations are seen in a number of any thoracic division of the carapace and they harvestman lineages; and are particularly com- still express segmental divisions of the opistho- mon among the tropical Laniatores. The ventral soma as transverse furrows. Cyphophthalmids surface of the fossil is unknown. A reconstruc- are also typically much smaller (1–3 mm) and tion of the suggested appearance of the animal the new fossil lacks the characteristic raised in life is presented in Fig. 5. openings of the repugnatorial glands (ozophores) on the carapace which are autapomorphic for Affinities Cyphophthalmi. This fossil does not unequivocally resemble The large thorns on the opisthosoma are any particular living harvestman group, but in- reminiscent of spination in many genera of the stead preserves a mosaic of characters, some of morphologically diverse laniatores [see figures J.A. Dunlop. A new Carboniferous harvestman 73 in Roewer, 1923]. However, most laniatores lus. No living trogulid has such prominent (with a few exceptions) express some degree of opisthosomal spines. opisthosomal segmentation. Furthermore, this suborder can be more explicitly excluded since, Ceratolasmatidae like cypthopthalmids, laniatores do not express The family Ceratolasmatidae was established a divided carapace. Protective spines have clear- by Shear [1986]. Ceratolasmatid characters ex- ly arisen multiple times among different har- pressed by the Missouri fossil refer primarily to vestman clades. Unfortunately the pedipalps in opisthosomal spination. Like the fossil, mem- the fossil are equivocal. Large, raptorial pedi- bers of this family have the pustulate ornament palps are a laniatore autapomorphy. and at least one species, merickeli The divided carapace thus supports referral Shear, 1986 has a superficially very similar of this fossil to either the suborders Eupnoi or pattern of spination: two anterior spines arising Dyspnoi; see e.g., Giribet et al. [1999, 2002] from a single base followed by two more widely for a discussion of whether these two groups separated posterior spines [Shear, 1986: fig. form a monophyletic clade. Intuitively, Eupnoi 18]. However, when considered in detail this looks unlikely since the overwhelming majority spination differs from that in the fossil in that of eupnoid taxa have a prominent, raised eye the anterior spines in A. merickeli arise from the tubercle in the middle of the carapace, with a metapeltidium (i.e., the thoracic tergite of the further sulcus dividing the carapace immediate- carapace) while those in the fossil are clearly ly behind the eyes. However, like this fossil, a opisthosomal. Similarities to Ceratolasmatidae number of living eupnoids lack external opistho- are further weakened by the fact that these somal segmentation [e.g., Roewer, 1923]. Sig- extant harvestmen have a compact body retain- nificantly, the Missouri fossil shares gross mor- ing evidence of opisthsomal segmentation pos- phological characters with two groups among teriorly, a prominent eye tubercle with a large the Dyspnoi (the Trogulidae and the Ceratolas- spine and that other species have different pat- matidae) but lacks unequivocal diagnostic char- terns of spination [e.g., Shear, 1986: figs 23– acters of either. For this reason it is tentatively 29]. Given the likelihood that spination is ho- assigned to an unresolved, possibly basal, posi- moplastic within Opiliones, trogulid affinities tion within Dyspnoi and the two alternative place- for the Missouri fossil look, on balance, more ments are discussed in further detail below. convincing; although explicit autapomorphies of this family are not unequivocally preserved. Trogulidae Trogulid characters expressed by this fossil Species description include: (a) the overall body shape, which is somewhat elongate with a long, subtriangular Order Opiliones Sundevall, 1833 carapace, (b) the absence of opisthosomal seg- Suborder ?Dyspnoi Hansen et Sørensen, 1904 mentation (Giribet et al. [2002] scored a scutum Echinopustulus gen.n. magnum as present in Trogulus), (c) the finely pustulate cuticle ornament, and (d) a median ETYMOLOGY. Combination of Echino and band running along the length of the body [cf. pustulus for the spiny and pustulate nature of the Roewer, 1923: fig. 800]. The lack of an eye body. The gender is masculine. tubercle in the middle of the carapace is also DIAGNOSIS. Carboniferous harvestmen with a consistent with this group, but as noted above pustulate cuticle bearing two pairs of dorsal spines excavations of the anterior end of the carapace on an unsegmented opisthosoma. Anterior pair of failed to reveal either eyes or the one unequiv- spines originate close to centre of opisthosoma from a single tubercle; more posterior spines more widely ocal trogulid autapomorphy: a bilobed projec- separated. tion or hood. That said, the full extent of the REMARKS. The new genus reflects the rather carapace could not be revealed within the nod- unique spiny morphology which is not seen in any ule and from published figures a hood is also other putative Carboniferous harvestman; or indeed equivocal in the putative fossil trogulid Eotrogu- any other described Palaeozoic arachnid. 74 EUROPEAN ARACHNOLOGY 2003

Echinopustulus samuelnelsoni sp.n. Cokendolpher J.C. & Cokendolpher J.E. 1982. Reexami- Figs 1–5. nation of the Tertiary harvestmen from the Florissant Formation, Colorado (Arachnida: Opiliones: Palpa- tores) // J. Paleont. Vol.56. P.1213–1217. MATERIAL. Holotype and only known specimen. Cokendolpher J.C. & Poinar G.O. 1998. A new fossil Peabody Museum (repository number: YPM 204165), harvestman from Dominican Republic amber (Opil- Yale, USA. iones, Samoidae, Hummelinckiolus) // J. Arachnol. ETYMOLOGY. Named at Elliot Nelson’s re- Vol.26. P.9–13. quest for his late father, who encouraged his interest Dunlop J.A. 2004. The enigmatic fossil arachnid Kusta- in natural history. rachne tenuipes Scudder, 1890 is a harvestman // Samu DIAGNOSIS. As for the genus. F. & Szinetár C. (eds.), European Arachnology 2002. DISTRIBUTION. Upper Carboniferous Pleas- Proc. 20th European Coll. Arachnol. 2002. P.17–25. Dunlop J.A. & Giribet G. 2003. The first fossil cyphoph- anton Group of western Missouri, USA; possibly thalmid (Arachnida: Opiliones) from Bitterfeld am- near the town of Windsor. ber, Germany // J. Arachnol. Vol.31. P.371–378. DESCRIPTION. Total preserved body length Dunlop J.A., Anderson L.I., Kerp H. & Hass H. 2003. 8.7 mm. Maximum preserved carapace length 2.8 Preserved organs of Devonian harvestmen // Nature. mm. Carapace subtriangular, basal width 3.4 mm, Vol.425. P.916. divided towards posterior end by straight, trans- Giribet G., Edgecombe G.D., Wheeler W.C. & Babbitt C. 2002. Phylogeny and systematic position of Opil- verse sulcus. Eyes and pedipalps equivocal. Leg iones: a combined analysis of chelicerate relation- series incomplete, but trochanters bulbous, length c. ships using morphological and molecular data // Cla- 0.8 mm. Legs long and slender. Leg 1 femur 4.3 mm distics. Vol.18. P.5–70. long. Femur of leg 3 at least 4.1 mm long. Leg 4 Giribet G., Rambla M., Carranza S., Baguñà J., Riutort M. indistinct, but slender. Opisthosoma oval, broadly & Ribera C. 1999. Phylogeny of the arachnid order joined to prosoma via a procurved sulcus. Opistho- Opiliones (Arthropoda) inferred from a combined approach of complete 18S and partial 28S ribosomal soma dome-like and highly vaulted; standing about DNA sequences and morphology // Mol. Phylogenet. 2 mm proud of the nodule surface in the part. Cuticle Evol. Vol.11. P.296–307. splayed out laterally on one opisthosomal margin. Haupt H. 1956. Beitrag zu Kenntnis der eözanen Arthro- Total opisthosoma length 5.9 mm; maximum width podenfauna des Gieseltales // Nova Acta Leopold., 4.3 mm. Dorsal surface of both carapace and opistho- N.S. Bd.128. S.1–90. soma ornamented with dense pattern of minute pus- Howe W.B. 1982. Stratigraphy of the Pleasanton Group, Pennsylvanian System in Missouri // Missouri Depart- tules; absent from carapace margins and a weakly ment of Natural Sources, Division of Geology and Land defined median band. Median band, width c. 0.5 Survey, Open File Report Series OFRT-82-10-GI. 114 p. mm, extends some 7 mm along the body from the Martens J. 1978. Spinnentiere, Arachnida. Weberknechte, middle of the carapace down onto the opisthosoma. Opiliones // Die Tierwelt Deutschlands. Bd.64. 464 S. Opisthosoma bears two pairs of spines preserved as Petrunkevitch A.I. 1913. A monograph of the terrestrial Palaeozoic Arachnida of // Trans. spine bases (diameter c. 0.4 mm) on part and as deep Connect. Acad. Arts Sci. Vol.18. P.1–137. holes in counterpart. Anterior pair paramedian, Petrunkevitch A.I. 1955. Arachnida // Moore R.C. (ed.), emerging dorsally from a single, centrally posi- Treatise on Invertebrate Palaeontology, Part P, Ar- tioned, heart-shaped tubercle; diameter c. 1.1 mm. thropoda 2. University of Kansas Press, Lawrence, Posterior pair emerge postero-laterally at a separa- Kansas. P.42–162. tion of c. 2.0 mm from each other. Roewer C.F. 1923. Die Weberknechte der Erde. Jena: Gustav Fischer. 1116 S. ACKNOWLEDGEMENTS. I am very grateful Scudder S.H. 1890. Illustrations of the Carboniferous Arachnida of North America // Mem. Boston Soc. Nat. to E. Nelson for making this specimen available for Hist. Vol.4. P.443–456. study. I also thank M. Florence (USNM) and T. Shear W.A. 1986. A cladistic analysis of the opilionid super- White (YPM) for the loan of material in their care, family Ischyropsalidoidea, with descriptions of the new Agnes Rage (MNHN) and M. Hellmund (Halle) for family Ceratolasmatidae, the new genus Acuclavella, and information about fossil type material, B. Sutton four new species // Am. Mus. Novit. No.2844. P.1–29. and B. Stinchcomb for valuable information about Starêga W. 2002. Baltic amber harvestmen (Opiliones) fossil sites in Missouri and the reviewers for useful from Polish collections // Ann. Zool. (Warsaw). Vol.54. comments on an earlier version of the manuscript. No.4. P.601–604. Thevenin A. 1901. Sur la découverte d’arachnides dans le terrain houiller de Commentry // Bull. Soc. Géol. Fr. References Ser.4. Vol.1. P.605–611. Wood S.P., Panchen A.L. & Smithson T.R. 1985. A Beall B.S. 1986. Reinterpretation of the Kustarachnida terrestrial fauna from the Scottish Lower Carbonifer- (Abstract) // Am. Arachnol. Vol.34. P.4. ous // Nature. Vol.314. P.355–356.