Karumballichirus lakhraensis

Hyžný, Matúš, Kneer, Dominik & Charbonnier, Sylvain, 2025, The largest ghost shrimps ever: evidence from the fossil record and implications for the maximum size estimate of callianassoid burrowing ghost shrimps, Acta Palaeontologica Polonica 70 (1), pp. 97-113 : 101-104

Karumballichirus lakhraensis (Hyžný & Charbonnier in Hyžný et al., 2016a) comb. nov.

Figs. 3 , 4 .

2013 Calliax sp. ; Charbonnier et al. 2013: 106, fig. 2A, B.

2016a Neocallichirus lakhraensis Hyžný and Charbonnier in Hyžný et al., 2016a: 346, figs. 4, 5A 2, B 2, C 3, D 2, E 2, 6 H.

Material.— Holotype: CPAG.RAN.I.64 (cast MNHN.F. A52414), right propodus with articulated dactylus; paratypes: CPAG.RAN.I.65–I.72 (casts MNHN.F. A52415 –A52422), 4 additionalspecimens: CPAG.RAN.I.85–I.87(castsMNHN.F.

A91718 – A91720 ), largely articulated chelipeds consisting of dactylus, propodus, carpus, merus, and ischium; all from Rhob Nala section (Lakhra Formation, Ypresian), Thatta District , Sindh, Pakistan; MNHN.F.A47685, right major propodus, Lakhra Dome coal mine field (Bara Formation, Paleocene, Thanetian?), Thatta District, Sindh, Pakistan .

Description.— Detailed description of the species was provided by Hyžný et al. (2016a) and is therefore not repeated here.

Remarks.— Hyžný et al. (2016a) assumed that the growth rate of Neocallichirus lakhraensis was largely the same as the one of Neocallichirus karumba ; the assumption was based on striking morphological similarities between both taxa as shown by Hyžný et al. (2016a: fig. 5). Based on an extrapolation of data on the growth of N. karumba ( Dworschak 2008) , Hyžný et al. (2016a) estimated the total length of the largest individuals of N. lakhraensis to be 110 mm. The establishment of Karumballichirus allows the re-assignment of N. lakhraensis to the respective genus.

Charbonnier et al. (2013) reported a single isolated propodus from the?Thanetian (upper Paleocene) of southern Pakistan. They interpreted it tentatively as a minor chela propodus of Calliax sp. Personal re-examination of the specimen by one of us ( MH) revealed that the specimen is not complete and what appeared to be a short fixed finger is actually part of a broken fixed finger, much larger than anticipated previously ( Fig. 4 ).

Stratigraphic and geographic range.—?Thanetian (upper Paleocene)–Ypresian (lower Eocene) of Pakistan ( Charbonnier et al. 2013; Merle et al. 2014; Hyžný et al. 2016a).

Karumballichirus maximus (A. Milne-Edwards, 1870) comb. nov.

Fig. 5 .

1870 Callianassa maxima ; Milne-Edwards 1870: 97, pl. 2: 5. non 1915 Callianassa maxima Milne-Edwards, 1870 ; Kemp 1915:

252, pl. 13: 1–5. non 1954 Callianassa maxima Milne-Edwards, 1870 ; Pillai 1954: 23,

figs. 1–5. non 1981 Callianassa ( Callichirus) maxima Milne-Edwards, 1870 ;

Daniel 1981: 193, pl. 6: 1A–I.

Material.— Lectotype: MNHN.F.A74264, left major chela (propodus and dactylus) ( Fig. 5A ; Milne-Edwards 1870: pl. 2: 5); paralectotype: MNHN.F.A74265, right major chela (propodus and dactylus) ( Fig. 5B ). The type material was originally composed of several syntypes, the two of which were recently rediscovered by one of us (SC) in the palaeontological collections at the MNHN, Paris.

Description.—Major cheliped manus subquadrate; upper and lower margins keeled and distinctly serrated, especially the lower one; lower margin concave at junction with fixed finger; distal margin with large, sharp tooth at articulation with dactylus. Inner and outer lateral surfaces densely covered with evenly spaced tubercles. Major cheliped fixed finger approximately as long as manus; lateral surface with faint ridge with row of seven large tubercles running onto manus; occlusal surface unarmed. Major cheliped dactylus long and slender, approximately four times longer than high; upper margin proximally adorned with tubercles; lateral surfaces tuberculated proximally and adorned with complex setal pores; occlusal margin armed with complex molariform protuberance proximally with two blunt teeth and followed by a gap, one peg-like blunt tooth, another gap and a saw-like series of teeth ending with a sharp curved fingertip.

Remarks.— Callianassa maxima was described based on several subfossil chelae found during the construction of a channel in the territory of present-day Thailand ( Milne-Edwards 1870). Kemp (1915), Pillai (1954) and Daniel (1981) provided a more detailed description based on more complete material from India, including larval stages ( Daniel 1981). Sakai (1999), however, argued that the material of Kemp (1915) differs from C. maxima and erected a new species for it, Neocallichirus kempi . Dworschak (2008) re-investigated the specimens attributed at that time to C. maxima (except its type material) and N. kempi , and considered them conspecific with Callianassa karumba ; Callianassa maxima was considered a separate species by Dworschak (2008). The type material of Callianassa maxima was considered lost ( Sakai 1999: 103) and found again in the collection of MNHN.F; photographs of it are provided herein for the very first time. The material has been suggested to conform to the intraspecific variation of K. karumba (Peter C. Dworschak, personal communication 2019). However, we have not studied the type material of C. karumba and N. kempi first-hand, so we are reluctant to synonymise these taxa with C. maxima at present.

It should be noted that C. maxima was described based on more than one specimen, as is clearly mentioned by Milne-Edwards (1870: 97–98). However, all subsequent authors erroneously stated that it was described based on a single subfossil chela ( Kemp 1915: 252; Pillai 1954: 23; Daniel 1981: 193; Sakai 1999: 103; Dworschak 2008: 75).

Schweitzer et al. (2010) incorrectly attributed the authorship of C. maxima to A. Milne-Edwards (1860) instead of Milne-Edwards (1870).

Stratigraphic and geographic range.—Holocene (subfossil strata) of Thailand (A. Milne-Edwards 1870).

Karumballichirus tuberculatus (Lőrenthey in Lőrenthey and Beurlen, 1929) Fig. 6 .

1929 Calianassa [sic!] tuberculata Lőrenthey ; Lőrenthey and Beurlen 1929: 51, pl. 1: 9.

2006 Neocallichirus borensis ; Beschin et al. 2006: 97, fig. 2, pl. 1: 4–6.

2016 Neocallichirus tuberculatus (Lőrenthey in Lőrenthey and Beurlen, 1929); Hyžný et al. 2016a: 350, fig. 6D–F.

2020 Karumballichirus tuberculatus (Lőrenthey in Lőrenthey and Beurlen, 1929); Hyžný and Zorn 2020: 21, pl. 5: 3–5. [cum. syn.]

Material.— Callianassa tuberculata syntypes: MBFSZ E9465 ( 16 specimens with collective repository number), isolated major cheliped elements (carpus, propodus, dactylus) from the middle Eocene of Kosd , Hungary ; Neocallichirus borensis holotype: MCZ 2423 , isolated left major propodus from the Eocene ( Priabonian) of Priabona, Italy ; additional specimens: GA 2010/035/0021, isolated left major propodus from the Eocene ( Guttaring Group) of Guttaring, Austria ; GA 2010/266/0001, isolated right major propodus with broken fixed finger from the Eocene of Meledo Basso , Italy ; GA 2010/029/0008, incomplete right major propodus from the Eocene ( Priabonian ) of Mortisa, Belluno, Italy .

Description.—A detailed description of the species was provided by Lőrenthey and Beurlen (1929) and is therefore not repeated here.

Remarks.—Lőrenthey in Lőrenthey and Beurlen (1929) described Callianassa tuberculata based on a number of fragmentary specimens from the middle Eocene of Hungary. It is important to note that his figure (Lőrenthey in Lőrenthey and Beurlen 1929: pl. 1: 9) is a reconstruction and does not represent any particular specimen from the studied sample. Nevertheless, the largest fragment probably belonged to an animal with a total length exceeding 180 mm, as already suggested by Hyžný et al. (2016a). Neocallichirus borensis , originally described from the upper Eocene of Italy ( Beschin et al. 2006), has recently been considered a junior subjective synonym of Callianassa tuberculata by Hyžný and Zorn (2020). They also reassigned the species to the genus Karumballichirus .

Stratigraphic and geographic range.—Eocene of Hungary ( Lőrenthey and Beurlen 1929), Italy ( Beschin et al. 2006; Hyžný and Zorn 2020), and Austria ( Hyžný and Zorn 2020).

Figures

Fig. 3. Ghost shrimp Karumballichirus lakhraensis (Hyžný & Charbonnier in Hyžný et al., 2016a) comb. nov., Ypresian (Eocene) of Thatta District, Sindh, Pakistan. A. CPAG.RAN.I.64 (holotype), right major chela (propodus and dactylus) in outer lateral (A1) and inner lateral (A2) views. B. CPAG. RAN.I.85 (cast MNHN.F.A91718), left major chela (incomplete propodus and dactylus).C. CPAG.RAN.I.86 (cast MNHN.F.A91719), left major chela in inner lateral (C1) and outer lateral (C2) views. D. CPAG.RAN.I.87 (cast MNHN.F.A91720), right major dactylus in outer lateral view.E. CPAG.RAN.I.70 (paratype), right major cheliped (ischium, merus, incomplete carpus) in outer lateral view.All specimens are shown to the same scale. Specimens in B–D were covered with ammonium chloride prior to photography.

Fig. 4. Ghost shrimp Karumballichirus lakhraensis (Hyžný & Charbonnier in Hyžný et al., 2016a) comb. nov., Paleocene of Lakhra Dome coal mine field (BaraFormation,Paleocene,Thanetian?),Pakistan.MNHN.F.A47685, right major propodus in outer lateral (A1), inner lateral (A2), and ventral A3) views.

Fig.5. Ghost shrimp Karumballichirus maximus (Milne-Edwards, 1870) comb.nov.from the Holocene (subfossil strata) of Thailand.A.MNHN.F.A74264 lectotype), left major chela (propodus and dactylus) in outer lateral (A1), proximal (A2), inner lateral (A3), ventral (A4), and dorsal (A5) views, the occlusal view of dactylus (A6). B. MNHN.F.A74265 (paralectotype), right major chela (propodus and dactylus) in outer lateral (B1) and inner lateral (B2) views, occlusal view of dactylus (B3).

Fig. 6. Ghost shrimp Karumballichirus tuberculatus (Lőrenthey in Lőrenthey and Beurlen, 1929), middle Eocene of Kosd, Hungary. A–F. MBFSZ E9465 (syntype collection of Callianassa tuberculata), consisting of isolated major cheliped elements: carpus (A), propodus (C, D), fixed finger (A, F), and dactylus (B, E).