Neocallichirus Sakai, 1988

Hyžný, Matúš, Charbonnier, Sylvain, Merle, Didier, Lashari, Rafique Ahmed, Bartolini, Annachiara & Métais, Grégoire, 2016, New Early Cenozoic ghost shrimps (Decapoda, Axiidea, Callianassidae) from Pakistan and their palaeobiogeographic implications, Geodiversitas 38 (3), pp. 341-353 : 344-348

Genus Neocallichirus Sakai, 1988

TYPE SPECIES. — Neocallichirus horneri Sakai, 1988 , by original designation.

INCLUDED FOSSIL SPECIES. — See Garassino et al. (2011) and Hyžný & Karasawa (2012) for updated lists.

COMMENTS. — The genus was erected by Sakai (1988), but because of its rather broad original diagnosis, it underwent numerous reconsiderations. As a consequence, taxonomic composition of Neocallichirus is complex, and was partly discussed by Hyžný & Karasawa (2012). Interestingly, Sakai himself has used several different concepts of the genus since its first description ( Sakai 1988: 61; 1999: 84; 2005: 160; 2011: 451; see also Manning & Felder 1991: 779). The identification of the genus in the fossil record has been discussed by several authors ( Schweitzer & Feldmann 2002; Schweitzer et al. 2004, 2006; Hyžný & Hudáčková 2012; Hyžný & Karasawa 2012), however, the revision of all fossil taxa treated at one time under Neocallichirus is still pending. As already noted previously ( Hyžný & Hudáčková 2012; Hyžný & Karasawa 2012), the genus Neocallichirus as usually recognized in the fossil record may represent a mixture of several closely allied genera.

Because the fossil material described herein is morphologically close to Callianassa karumba currently classified within Neocallichirus ( Sakai 1999, 2005, 2011; Dworschak 2008), we treat our new material as remains of representatives of this genus. However, it should be noted that N. karumba exhibits important differences from the type species of Neocallichirus ( Dworschak 2008: 83) . Because generic reconsideration of Callianassa karumba is beyond the scope of the present contribution, two new fossil species described herein are treated tentatively as Neocallichirus .

Neocallichirus khadroensis Hyžný & Charbonnier , n. sp. ( Figs 2 ; 5A 3 , C 2 , D 3 ; 6I )

“fragments of chelae of an Uca or Cardisoma ” – Stoliczka 1871: 2, pl. 1, figs 3-10.

ETYMOLOGY. — The specific epithet refers to the Khadro Formation where the type material was collected.

TYPE MATERIAL.— Holotype (CPAG.RAN.I.55,castMNHN.F.A52405); 8 paratypes (CPAG.RAN.I.56-I.63, castsMNHN.F.A52406- A52413 ).

TYPE LOCALITY. — Gawar Band section (25°53’48.44’’N, 67°49’58.49’’E), Ranikot District, Sindh, Pakistan.

TYPE AGE. — Paleocene, Danian (Khadro Formation, Lower Ranikot Group).

STRATIGRAPHIC RANGE. — Danian ( Pakistan) – Aquitanian? ( India).

DIAGNOSIS. — Ghost shrimp with major P1 merus with spinose lower margin and large proximal hook; major P1 manus (palm) rectangular with tuberculated lateral surfaces and distal margin with large notch and/or prominent tooth just below the articulation with dactylus; major P1 dactylus approximately as long as manus (palm) with two blunt proximal spines on its upper margin and occlusal margin strongly armed with a stout and blunt tooth with three apices proximally followed with a broad gap, additional large tooth and several small teeth decreasing in size distally.

MEASUREMENTS (IN MM). — CPAG.RAN.I.55 (holotype): mpl = 21.2, mph = 23.4; CPAG.RAN.I.56 (paratype): mpl = 23, mph = 25; CPAG.RAN.I.57 (paratype): mpl = 15.2, mph = 17.5; CPAG.

RAN.I.58 (paratype): mpl = 22.8, mph = 27.2; CPAG.RAN.I.60 (paratype): mpl = 13.7, mph = 18.3; CPAG.RAN.I.61 (paratype): mpl = 17.4, mph = 21.7; CPAG.RAN.I.62 (paratype): mpl = 18.3,

mph = 22.4. Additionally 19 specimens deposited under collective number CPAG.RAN.I.76 were measured and evaluated graphically ( Fig. 3A ).

DESCRIPTION

Major P1

Merus approximately two times longer than high, with longitudinal keel running along the midline of the outer lateral surface, upper margin slightly convex and smooth, lower margin armed with prominent spines and large proximal hook. Carpus poorly preserved, distal portion unknown. Propodus stout, manus (palm) quadrate in outline or slightly higher than long, upper and lower margins parallel to each other, upper margin keeled and smooth, lower margin keeled and strongly serrated, distal margin usually with large notch and prominent tooth just below the articulation with dactylus; both outer and inner lateral surfaces covered with densely packed tubercles, tuberculation usually not reaching the upper third of the lateral surface, largest tubercles positioned close to the articulation with dactylus; inner propodal surface with large setal pits positioned at the upper margin distally; fingers approximately as long as manus (palm) or slightly longer; fixed finger slender, incurved distally, tip bent slightly upward, occlusal surface edentulous. Dactylus long and deep, upper margin with two spines proximally, occlusal surface strongly armed with a stout and blunt tooth with three apices proximally followed with a broad gap, additional large tooth and several small teeth decreasing in size distally, tip of dactylus hooked.

Minor P1, P2-P5, other appendages, carapace and pleon Unknown.

COMMENTS

Stoliczka (1871: 2) described and figured some isolated chelae as remains “apparently one of the Grapsidae , an Uca or Cardisoma , or some other allied genus.” In fact, the description and figures fully conform with Neocallichirus khadroensis Hyžný & Charbonnier , n. sp. as described herein. Stoliczka (1871: 2) reported this material from “a yellowish brown argillaceous rock between Soojapoor and Badra, south of Mhurr in Kutch”. The age of the outcrops is not specified and might be Aquitanian after Biswas (1992).

Comparison of N. khadroensis Hyžný & Charbonnier , n. sp. with related species is given under comments of Neocallichirus lakhraensis Hyžný & Charbonnier , n. sp.

Neocallichirus lakhraensis Hyžný & Charbonnier , n. sp. ( Figs 4 ; 5A 2, B 2 , C 3 , D 2, E 2 ; 6H )

ETYMOLOGY. — The specific epithet refers to the Lakhra Formation from which the type material has been collected.

TYPE MATERIAL. — Holotype (CPAG.RAN.I.64, cast MNHN.F.A52414); 8 paratypes (CPAG.RAN.I.65-I.72, casts MNHN.F. A52415 -A52422).

TYPE LOCALITY. — Rbod Nala section (24°59’43.36’’N, 68°10’42.46’’E), Jhirak District, Sindh, Pakistan.

TYPE AGE. — Eocene, Ypresian (Lakhra Formation, Upper Ranikot Group).

STRATIGRAPHIC RANGE. — Ypresian ( Pakistan).

DIAGNOSIS. — Ghost shrimp with major P1 ischium with spinose lower margin; major P1 merus with spinose lower margin and large bifid proximal hook; major P1 manus (palm) rectangular with tuberculated lateral surfaces and ridge along the fixed finger, distal margin with large notch and/or prominent serrated tooth just below the articulation with dactylus; major P1 dactylus approximately as long as manus (palm) or longer with two blunt proximal spines on its upper margin and occlusal margin strongly armed with pegshaped teeth decreasing in size distally; minor P1 carpus elongated, approximately 2.5 times longer than high, fingers without armature.

MEASUREMENTS (IN MM). — CPAG.RAN.I.64 (holotype): mpl = 17.6, mph = 24.2; CPAG.RAN.I.65 (paratype): mpl = 16.7, mph = 23; CPAG.RAN.I.66 (paratype): mpl = 15.6, mph = 19.4; CPAG. RAN.I.68 (paratype): mpl = 15.2, mph = 18.7; CPAG.RAN.I.71 (paratype): mpl = 12, mph = 15.1; CPAG.RAN.I.72 (paratype): mpl = 18.6, mph = 25.7. Additionally nine specimens deposited under collective number CPAG.RAN.I.77 were measured and evaluated graphically ( Fig. 3B ).

DESCRIPTION

Major P1

Ischium longer than high with spinose lower margin. Merus approximately two to three times longer than high, with longitudinal keel running along the midline of the outer lateral surface; lower half of the lateral surface tuberculated; upper margin slightly convex and smooth, lower margin armed with prominent spines and large bifid proximal hook. Carpus distinctly higher than long, upper margin straight, proximolower margin serrated; articulation with propodus distinctly shorter than the entire length of proximal margin. Propodus stout, manus (palm) approximately as long as high, or higher than long; upper and lower margins parallel to each other, or slightly converging distally; upper margin keeled and smooth, lower margin keeled and strongly serrated, distal margin with large notch accompanied with a tooth, or only with a large triangular serrated tooth, just below the articulation with dactylus; both outer and inner lateral surfaces covered with unevenly spaced tubercles, inner surface containing fewer tubercles; fingers approximately as long as manus (palm) or distinctly longer; fixed finger slender with tuberculated ridge along its lateral surface, tip bent slightly upward, occlusal surface edentulous or armed with small teeth and with one blunt tooth at the midlength. Dactylus long and deep, upper margin with two spines proximally, occlusal surface strongly armed with peg-shaped teeth decreasing in size distally, tip of dactylus hooked.

Minor P1

Merus approximately 2.5 times longer than high, poorly preserved. Carpus approximately 2.5 times longer than high, upper and lower margins parallel to each other, proximo-lower border rounded. Propodus elongated, manus (palm) slightly longer than high, upper and lower margins parallel to each other; fixed finger approximately as long as manus (palm), occlusal surface edentulous. Dactylus long and slender, as long as fixed finger, not armed.

P2

Merus slender, longer than high. Carpus triangular in outline, diverging distally. Propodus approximately as long as high; fingers short.

P3

Poorly preserved.

P4-P5, other appendages, carapace and pleon

Unknown.

COMMENTS

Neocallichirus lakhraensis Hyžný & Charbonnier , n. sp. differs from N. khadroensis Hyžný & Charbonnier , n. sp. by the arrangement of the teeth on the occlusal surface of the P1 dactylus ( Fig. 5A 2 , 3 ) and the presence of welldeveloped granulated ridge along the fixed finger which is lacking in N. khadroensis Hyžný & Charbonnier , n. sp. Especially females of N. lakhraensis Hyžný & Charbonnier , n. sp. possess well-developed longitudinal ridge on the fixed finger ( Figs 4F ; 5D 2 ).

Morphologically, both above discussed species are remarkably similar to extant N. karumba (see comparisons in Fig. 5 ). Outline of the major P1 merus is virtually identical, as well as its armature and tuberculation ( Fig. 5C 1-3 ). Neocallichirus karumba , however, possesses large elongated setal pores on the lateral surface of dactylus, at least in large males; such setal pores are missing in the material from Pakistan. Major difference which can be considered as taxonomically important on the species level is the development of the tooth below the articulation with dactylus and the tuberculation in the area of the notch. These characters are different in all three taxa. Large tubercles serving as bases of the tufts of setae on the propodal surface close to articulation with dactyli are present invariably in all specimens of N. karumba figured by Dworschak (2008), but they are absent in two new species described herein.

From fossil species, N. khadroensis Hyžný & Charbonnier , n. sp. and N. lakhraensis Hyžný & Charbonnier , n. sp. are rather close to Callianassa tuberculata Lőrenthey in Lőrenthey & Beurlen, 1929, from the Middle Eocene of Hungary and N. borensis Beschin, De Angeli, Checchi & Mietto, 2006 , from the Late Eocene (Priabonian) of Italy ( Fig. 6 A-C). Both species shares with the Pakistani material general shape of propodus, tuberculation at the base of the dactylus and lateral surfaces of propodus. Neocallichirus borensis has several large tubercles in a row with setal pores on their tops, and in this respect it is very close to N. karumba , but differs from N. khadroensis Hyžný & Charbonnier , n. sp. and N. lakhraensis Hyžný & Charbonnier , n. sp. Callianassa tuberculata , herein considered congeneric with all above mentioned species, shares with N. lakhraensis Hyžný & Charbonnier , n. sp. similar armature of the dactylus, but differs in rather restricted tuberculation of the propodus and possession of large setal pores on the dactylus ( Fig. 5D 2 ). Additionally, there is Callianassa maxima A. Milne-Edwards, 1870 ( Fig. 6 J-L), known only from a single (and apparently lost, see Sakai 1999: 103) subfossil specimen from Thailand (see Dworschak 2008: 75 for more details on other possible occurrences), which demonstrates a mixture of above mentioned characters including strong tuberculation and well-developed tooth-formula on the occlusal surface of dactylus. The species has been treated as Neocallichirus by Sakai (2011) and Hyžný & Karasawa (2012) and has confusing taxonomic history which does not need to be repeated here (for details see Dworschak 2008: 75, and Sakai 2011: 459).

There is one more fossil ghost shrimp reported from the Early Cenozoic of Pakistan, and hence Neocallichirus wellsi from the Drazinda Formation (Priabonian) of Domanda region (NW Frontier Province, Pakistan). Neocallichirus wellsi differs substantially from both new species from Pakistan with rectangular propodus converging distally with proportionately short fingers, distinctly longer carpus and merus with dissimilar armature on its lower margin ( Schweitzer et al. 2004: fig. 4a-f).

Figures

FIG. 2. — Neocallichirus khadroensis Hyžný & Charbonnier,n. sp. from the nodules of the Gawar Band section (Danian,Khadro Formation), Ranikot District,Sindh,Pakistan:A, holotype CPAG.RAN.I.55, major left male P1 chela (propodus with articulated dactylus) showing occlusal margin of dactylus,outer view;B, paratype CPAG. RAN.I.56, major right male P1 propodus showing fixed finger with smooth occlusal margin, inner view; note a smaller major right P1 propodus; C, paratype CPAG. RAN.I.57,major left male P1 chela (propodus with articulated dactylus),inner view;D-F, paratype CPAG.RAN.I.58,major right male P1 propodus in outer (D), frontal (E) and inner (F) views; G, paratype CPAG.RAN.I.61, major left male P1 propodus,outer view;H, I, paratype CPAG.RAN.I.59,major right female P1 propodus with broken fixed finger in outer (H) and inner (I) views; J, paratype CPAG.RAN.I.63, major right P1 merus, outer view; K, paratype CPAG.RAN.I.62, major left male P1 propodus, inner view;L, paratype CPAG.RAN.I.60,major left male P1 propodus preserved in a sandy nodule,outer view.Photographs:L. Cazes and P.Loubry.Scale bar:10 mm.

FIG. 5. — Comparison of extant and extinct Neocallichirus chelipeds:A, major male P1 chela of Neocallichirus karumba (Poore & Griffin,1979) (A1),N.lakhraensis Hyžný & Charbonnier, n. sp., holotype CPAG.RAN.I.64 (A2) and N. khadroensis Hyžný & Charbonnier, n. sp., holotype CPAG.RAN.I.55 (A3); B, major P1 carpus of N. karumba (B1) and N. lakhraensis Hyžný & Charbonnier, n. sp.,paratype CPAG.RAN.I.69 (B2); C, major P1 merus of N.karumba (C1), N. khadroensis Hyžný & Charbonnier, n. sp., paratype CPAG.RAN.I.63 (C2) and N.lakhraensis Hyžný & Charbonnier,n. sp.,paratype CPAG.RAN.I.69 (C3); D, major female P1 chela of N. karumba (D1), N.lakhraensis Hyžný & Charbonnier,n. sp., paratype CPAG.RAN.I.66 (D2) and N. khadroensis Hyžný & Charbonnier,n. sp., paratype CPAG.RAN.I.59 (D3); E, minor P1 cheliped of N.karumba (E1) and N. lakhraensis Hyžný & Charbonnier,n.sp.,paratype CPAG.RAN.I.72 (E2).Specimens of N.karumba are deposited under NHMW 21937 (male) and NHMW 21938 (female).Photographs of extant specimens (immersed in alcohol):M.Hyžný;photographs of fossil specimens:L. Cazes and P.Loubry.Scale bars:10 mm.

FIG. 3. — Measurements of major propodus in fossil ghost shrimps from Gawar Band and Rbod Nala sections, Pakistan: A, measurements in Neocallichirus khadroensis Hyžný & Charbonnier, n. sp.; B, measurements in Neocallichirus lakhraensis Hyžný & Charbonnier, n. sp. Graphs: M. Hyžný.

FIG. 6. — A-C, Neocallichirus borensis Beschin, De Angeli, Checchi & Mietto, 2006; A, B, holotype MCZ 2423; C, MCZ 2427; D-G, Neocallichirus tuberculatus (Lőrenthey in Lőrenthey & Beurlen, 1929) n. comb.; D-F, syntypes MFGI E.9465; H, Neocallichirus lakhraensis Hyžný & Charbonnier, n. sp., holotype CPAG. RAN.I.64; I, Neocallichirus khadroensis Hyžný & Charbonnier, n. sp., holotype CPAG.RAN.I.55; J-L, Neocallichirus maximus (A. Milne-Edwards, 1870). Photographs: M. Hyžný (A-F), and L. Cazes and P. Loubry (H-I). Scale bar: A-I, 10 mm. J-L, not to scale.

FIG. 4. — Neocallichirus lakhraensis Hyžný & Charbonnier, n. sp. from the Rbod Nala section (Ypresian, Lakhra Formation), Jhirak District, Sindh, Pakistan: A, B, paratype CPAG.RAN.I.65, major right male P1 chela (propodus with articulated dactylus) in outer (A) and inner (B) views; C, paratype CPAG.RAN.I.68, major right female P1 propodus with broken fixed finger, outer view; D, E, holotype CPAG.RAN.I.64, major right male P1 chela (propodus with articulated dactylus) in outer (D) and inner (E) views; F, paratype CPAG.RAN.I.66, major right female P1 chela (propodus with articulated dactylus), outer view; G, H, paratype CPAG. RAN.I.72, male with left major P1 cheliped showing propodus, carpus and merus (G) and right minor P1 cheliped showing merus, carpus,propodus and dactylus (H); I, paratype CPAG.RAN.I.70, major right P1 ischium with articulated merus and fragmentary carpus, outer view; J, paratype CPAG.RAN.I.71, major right male P1 cheliped (merus, carpus, propodus, dactylus), outer view; K, paratype CPAG.RAN.I.69, major left female P1 cheliped (dactylus, propodus, carpus, merus, ischium) with associated remains of P2 and P3. Photographs: L. Cazes and P. Loubry. Scale bar: 10 mm.

FIG. 1. — Simplified geological map (adapted from Hunting Survey Corporation, Ltd. 1961) of the Southern Kirthar Range,Southern Pakistan,showing the location of the fossil localities (Gawar Band and Rbod Nala).Line drawing:G.Métais.