Lepidophthalmus crateriferus (Hyžný & Dulai, 2014)

Hyžný, Matúš & Dulai, Alfréd, 2014, Deep-water fossorial shrimps from the Oligocene Kiscell Clay of Hungary: Taxonomy and palaeoecology, Acta Palaeontologica Polonica 59 (4), pp. 947-965 : 952-954

Lepidophthalmus crateriferus (Lőrenthey in Lőrenthey and Beurlen, 1929) comb. nov.

Figs. 2 , 3 .

1929 Calianassa [sic] craterifera sp. nov.; Lőrenthey in Lőrenthey and Beurlen 1929: 61, pl. 2: 12.

1929 Callianassa craterifera Lőrenthey in Lőrenthey and Beurlen 1929; Glaessner 1929: 79.

1939 Callianassa brevimanus sp. nov.; Beurlen 1939: 142, text-fig. 2, pl. 7: 5, 6.

1939 Callianassa craterifera Lőrenthey in Lőrenthey and Beurlen, 1929; Beurlen 1939: 143.

2010 Callianassa brevimanus Beurlen, 1939 ; Schweitzer et al. 2010: 34. 2010 Callianassa craterifera Lőrenthey in Lőrenthey and Beurlen, 1929; Schweitzer et al. 2010: 34.

Type material: Repeated search for the type material of Callianassa craterifera Lőrenthey in Lőrenthey and Beurlen, 1929, which was supposed to be deposited in the Hungarian Geological Institute in Budapest, was not successful, and thus we consider it lost. Beurlen (1939) did not designate a holotype for Callianassa brevimanus , so all his specimens are syntypes and we hereby designate HNHM M.59.4684a (a near complete major cheliped; Fig. 2C 1) as the lectotype. The remaining specimens are paralectotypes ( HNHM M.59.4683, M.59.4684b, M.59.4685, and M.59.4690). We hereby also select the lectotype of C. brevimanus to be the simultaneous neotype of Callianassa craterifera Lőrenthey in Lőrenthey and Beurlen, 1929. This action makes the C. brevimanus as an objective junior synonym of C. craterifera .

Type horizon: Upper Kiscellian (lowermost Chattian), Kiscell Clay Formation .

Type locality: Újlak brickyard at Óbuda , Budapest (site no longer available for study) .

Other material. ―A single specimen showing a near-complete major cheliped together with a partially preserved minor one ( HNHM M.59.4720); numerous cheliped fragments consisting of isolated propodi ( HNHM INV 2012.01 [collective number], KGP-MH OT-001–011), and dactyli ( KGP-MH OT-012–017); and several uncatalogued fragmentary specimens deposited in the Hungarian Geological and Geophysical Institute, Budapest.

Emended diagnosis. ―Strongly heterochelous callianassid shrimp; major cheliped merus ovoid and keeled laterally, low- er margin of merus with small hook proximally and rounded blade distally; carpus shorter than high, subrectangular with oblique lower margin; propodus broad, with keeled lower and upper margins, length of fixed finger approximately one-half length of palm; palm square, with several rounded tubercles laterally and with row of elongated setal pits in the upper part of mesial surface; supposed male morphotype propodus with distally directed tooth, tooth usually undercut by broad notch at base of fixed finger, fixed finger triangular with rounded tip; dactylus high and robust, occlusal margin with large molariform tooth; supposed female morphotype propodus with-

2

out tooth and notch, smoothly passing to fixed finger, lower margin of propodus convex at articulation with fixed finger.

Description. ―Major cheliped of presumed male massive. Merus ovoid, length about two times height, upper margin distinctly convex, lower margin with small sharp hook proximally and rounded blade distally ( Fig. 2A, C ), lateral surface with keel at midline or closer to the upper margin. Carpus distinctly shorter than high, subrectangular with straight upper and oblique lower margin, both terminated distally in angular corners ( Fig. 2A, C 1, D). Propodus broad, heavy, length of fixed finger subequal to or slightly exceeding one-half length of palm, articulation with carpus occupies the entire proximal margin. Palm square, slightly longer than high, lateral surface strongly convex with several rounded tubercles positioned at base of articulation with dactylus (e.g., Figs. 2B , 3A, C, G ), tubercles with setal pits resembling small craters, mesial surface flat, in upper part with row of up to ten large setal pits positioned parallel to each other ( Figs. 2E , 3D, E, J ); upper and lower margins of propodus distinctly keeled, keel on upper margin bent mesially in its proximal half, keel on lower margin bent gently mesially in its entire length; lower margin with setal pits arranged in regular distances; proximal margin straight; distal margin with subtriangular, distally directed tooth, tooth usually undercut by broad notch at base of fixed finger. Fixed finger triangular with rounded tip, tip sometimes bent gently upward, with well defined lateral and mesial margins, lateral one with serrated keel ( Fig. 2B ). Dactylus high and robust, upper margin strongly convex, occlusal margin with large molariform tooth, sometimes subdivided, tip sharp and bent downward, lateral surface of dactylus with large setal pits (e.g., Fig. 2A, C 1).

Major cheliped of presumed female very similar to presumed male in virtually all aspects. Differences concern mainly the shape of propodus: distal margin of propodus without tooth and notch, smoothly passing into fixed finger ( Fig. 3B, H ); lateral surface of propodus less armed. Lower margin convex at articulation with fixed finger.

Propodus of presumed minor cheliped higher than long, upper margin convex, distal margin smoothly passing to fixed finger; narrow fixed finger as long or slightly longer than palm ( Fig. 3I, K ); dactylus long, with distinct setal pits.

Dorsal carapace, abdomen and other appendages unknown.

Discussion. ―Lőrenthey in Lőrenthey and Beurlen (1929) described Calianassa [sic] craterifera on the basis of seven well preserved isolated propodi from the Upper Oligocene brickyard in Eger ( Bondor 1964; Kenawy and Nyírő 1967). Later, Beurlen (1939) described Callianassa brevimanus on the basis of several well preserved specimens from the Kiscell Clay. Unfortunately, he did not recognize common features between his species and C. craterifera , although he mentioned the latter taxon in his work. Both taxa share a general shape of the propodus, similar tuberculation on the lateral surface of the propodus at the articulation with dactylus, and also distinctive setal pits on the inner surface of propodus just below its upper margin (presence of similar setal pits have been figured also in Lepidophthalmus turneranus [de Man 1928: fig. 21c]). These pits which are present on the mesial surface of the propodus are not mentioned by Beurlen

1939). In most samples of C. brevimanus the specimens are preserved embedded in matrix usually with the lateral surface exposed, so the setal pits are therefore usually obscured by sediment. Only in one specimen, which is preserved as an imprint of the mesial surface, are these setal pits visible, and even then only when it was covered with ammonium chloride

Fig. 2E ). Beurlen (1939: pl. 7: 5) figured the same specimen, but the pits are, however, not discernible. In C. craterifera the pits have been sufficiently described and figured by Lőrenthey in Lőrenthey and Beurlen (1929: 62, pl. 2: 12). As a result, on the basis of morphological similarities together with roughly the same age of both taxa, C. brevimanus and

C. craterifera are considered synonymous, and reassigned to Lepidophthalmus as discussed above.

Lepidophthalmus crateriferus comb. nov. differs from all extant congeners. Many extant Lepidophthalmus species possess a proximally situated U-shaped notch on the upper margin of the merus which L. crateriferus comb. nov. lacks. The distal blade on the lower margin of merus is not denticulated as it is in many extant taxa. Lepidophthalmus crateriferus comb. nov. possesses a rather short carpus and a massive strongly vaulted propodus, and in this respect, it is closest to L. rosae (compare Sakai 2005: fig. 31A–C). Lepidophthalmus crateriferus comb. nov. has a deep dactylus with a single large molariform tooth (or keel) on the occlusal margin; such an armature is considered unique among Lepidophthalmus species.

Stratigraphic and geographic range. ―The species is so far known only from the Late Oligocene of Hungary.

Family Ctenochelidae Manning and Felder, 1991 Discussion. ―The family Ctenochelidae was erected by Manning and Felder (1991) to accommodate several genera previously classified within the family Callianassidae . De Grave et al. (2009) listed seven ctenochelid genera in four independent subfamilies, Callianopsinae Manning and Felder, 1991, Ctenochelinae Manning and Felder, 1991 , Gourretiinae Sakai, 1999a and Pseudogourretiinae Sakai, 2005. Sakai (2011) elevated the subfamilies to familial status, thus leaving Ctenochelidae as containing Ctenocheles only. Recently, Ctenocheloides attenboroughi Anker, 2010 , a new ctenochelid genus and species, has been described from very shallow marine environments of Madagascar.

Figures

Fig. 2. Fossorial shrimp Lepidophthalmus crateriferus (Lőrenthey in Lőrenthey and Beurlen, 1929) comb. nov., Óbuda in Budapest, Late Kiscellian. A. Left major cheliped of presumed male (HNHM M.59.4684b). B. Isolated left major propodus (HNHM M.59.4690). C. Left major cheliped of presumed male (C 1); neotype herein designated (lectotype of Callianassa brevimanus Beurlen, 1939) (HNHM M.59.4684a). Detail of C 1 under different light angle showing carpus and merus (C 2). Line drawing of merus depicted in C 2 (C 3). Note presence of distal meral hook and blade (see also white arrows in A and C 1). D. Presumed female specimen with both chelae (HNHM M.59.4720). E. Imprint of mesial surface of right major propodus (HNHM M.59.4683). Note setal pits close to upper margin of the chela.All specimens except HNHM M.59.4684a are paralectotypes of C. brevimanus selected herein.All specimens are figured to the same scale and were covered with ammonium chloride (except C ) prior to photography. Photographs by MH.

Fig. 3. Fossorial shrimp Lepidophthalmus crateriferus (Lőrenthey in Lőrenthey and Beurlen, 1929) comb. nov., Óbuda in Budapest, Late Kiscellian; presumed male morphotypes unless stated otherwise. A. Right major propodus (KGP-MH OT-007). B. Left major propodus articulated with dactylus of presumed female (KGP-MH OT-003). C. Left major propodus (KGP-MH OT-009). D. Left major propodus (KGP-MH OT-006). E. Fragmentary left major propodus (KGP-MH OT-008). F. Right major propodus (KGP-MH OT-010). G. Right major propodus (KGP-MH OT-001). H. Right major propodus of presumed female (KGP-MH OT-002). I. Right minor propodus of indeterminate sex (KGP-MH OT-011). J. Left major propodus of presumed female KGP-MH OT-005). K. Right minor propodus of indeterminate sex (KGP-MH OT-004). L. Left major dactylus (KGP-MH OT-017). M. Right major dactylus (KGP-MH OT-013). N. Right minor(?) dactylus (KGP-MH OT-012). O. Left major dactylus (KGP-MH OT-016). All elements are depicted in lateral aspect except D–F and J which are depicted in mesial view. All specimens are figured to the same scale and were covered with ammonium chloride prior to photography. Photographs by MH.