Plesiosminthus aff. conjunctus Ziegler, 1994

Freudenthal, Matthijs & Martín-Suárez, Elvira, 2017, A revision of European Plesiosminthus (Rodentia, Dipodidae), and new material from the upper Oligocene of Teruel (Spain), Palaeontologia Electronica 9 (1), pp. 1-25 : 10-11

Plesiosminthus aff. conjunctus Ziegler, 1994

Locality. Mirambueno 2A, MP27, Spain.

Material. Collection Naturalis-Leiden: 16 m 1, RGM 558532–558547; 14 m 2, RGM 558548–558561; 15 m 3, RGM 558562–558567, 558569–558577; 2 P4, RGM 558632–558633; 27 M1, RGM 558578– 558604; 19 M2, RGM 558605–558623; 8 M3, RGM 558624–558631. Collection Zaragoza: 3 m 1,

MIR2A 82–84; 5 m 2, MIR2A 85–89; 5 m 3, MIR2A

90–94; 6 M1, MIR2A 95–100; 9 M2, MIR2A 101–

109; 8 M3, MIR2A 111–118.

Measurements. Appendix 1, Figure 6 .

Description. Number of specimens in brackets.

m1—anteroconid absent (1), small (15), or with cingulum (2); anterolophulid absent (17) or present (1); metalophulid absent; protoconid hind arm transverse and high connected to the metaconid (18) or bent and high connected to the metaconid (1); ectolophid oblique; ectolophid complete (13), anteriorly interrupted (4), posteriorly interrupted (1), or isolated (1); mesoconid absent (9), weak (8), or strong (1); mesosinusid open (18) or closed (1); mesolophid reaches the border of the molar (11) or ends in a mesostylid (8); ectomesolophid absent; hypolophulid anterior oblique (1), anterior transverse (17), or transverse (1); hypoconid hind arm absent (15) or short (1); posterolophid continuous (14) or low connected (2); labial posterolophid absent (15) or small (2); in one specimen, there is a longitudinal connection metaconid-mesoconid.

m2—labial anterolophid present; metalophulid anterior complete (14) or connected to the anteroconid (4); protoconid hind arm absent (3), transverse and low connected to the metaconid (14), or bent and low connected to the metaconid (1); ectolophid longitudinal (11) or oblique (7); ectolophid complete (17) or anteriorly interrupted (1); mesoconid absent (12), weak (4), or strong (2); mesosinusid open (13) or closed (4); mesolophid reaches the border of the molar (16) or ends in a mesostylid (1); ectomesolophid absent (17) or weak (1); hypolophulid anterior oblique (2) or anterior transverse (16); hypoconid hind arm absent; posterolophid continuous (14) or low connected (1); labial posterolophid absent (12) or small (4); In one specimen, there is a longitudinal connection metaconid-mesoconid.

m3—lingual anterolophid long; labial anterolophid long; metalophulid absent (1), connected to the anteroconid (12), to anterolophulid (5), or to protoconid (2); protoconid hind arm absent (13), short and free (3), transverse and low connected to the metaconid (3), or long and ending free (1); sinusid open; sinusid narrow backwards (4) or broad backwards (16); mesosinusid open (3) or closed (16); mesolophid absent (1), of medium length (2), long (10), or reaching the border of the molar (6); ectomesolophid absent; entoconid absent (11), small (4), or large (2); hypolophulid anterior oblique (3) or anterior transverse (15); hypoconid hind arm absent; posterosinusid half closed (1) or closed (18); shape short triangle (5), long triangle (6), or trapezoid (8); in four specimens there is a longitudinal connection metaconid-mesoconid.

M1—anterocone absent; anterostyle absent; anterolophule continuous (31) or interrupted (1); antecingulum absent (11) or present (20); protolophule posterior plus a trace of an anterior connection (1) or posterior (32); sinus open (30) or there is an entostyle (2); sinus forward; mesosinus open; mesoloph reaching the border of the molar; entomesoloph absent; metalophule anterior (15) or transverse (18); posterosinus large and open (28), large and closed (1), or small and open (1).

M2—lingual anteroloph absent (10), weak (7), or strong (9); protolophule anterior (1), anterior plus incomplete posterior connection (2), transverse (4), or double (20); sinus open (27) or there is an entostyle (1); sinus strong forward (1) or forward (27); mesosinus open (15) or closed (10); mesoloph of medium length (1) or reaching the border of the molar (25), no mesostyle; entoloph-protocone connection high (3), low (17), or interrupted (5); metalophule anterior (13) or transverse (11);posterosinus large and open (17) or large closed (7).

M3—lingual anteroloph absent (14) or weak (1); protocone a distinct cusp (8) or a mere crest (7); protolophule to anterolophule; sinus absent (3), very small (6), small (4), or deep (2); neo-entoloph absent (2), low (2), or high (10); mesosinus open (6) or closed (9); mesoloph reaches the border of the molar (14) or connected to a mesostyle (2); old entoloph absent (9), curved spur (1), or complete (6); axioloph absent (2), short posterior spur (1), long posterior spur (6), complete (1), or = old entoloph (6); centroloph absent; centrocone absent (15) or isolated (1); metacone absent (5) or present (9); posterosinus open (1) or closed (12).

Plesiosminthus conjunctus from Herrlingen 8

is characterized by the primitive state of the pcdha of m2 (82% complete, never absent), combined with an advanced state of the protolophule of M2 (75% double). For an evaluation of "primitive" and "advanced" see the section on morphology values. These values are similar to those found in MIR2A (see Table 3 ). However, P. conjunctus from HERR8 is clearly larger than P. aff. conjunctus from MIR2A (see Figures 7-12 ). Other differences are: The protoconid hind arm of m3 is always absent in HERR8, and present, complete, or incomplete, in 35% of the specimens in MIR2A; the mesostylid is better developed in the m1, 2 from HERR8; the entoloph-protocone connection of M2 is more frequently interrupted in HERR8.

Figures

FIGURE 6. Scatter diagrams of molar length (L) and width (W) of Plesiosminthus aff. conjunctus (cross) and Plesiosminthus sp. (circle) from Mirambueno 2A, compared with the distribution area (rectangle) of Plesiosminthus conjunctus molars from HERR8 (in mm). 1, m1; 2, m2; 3, m3; 4, M1; 5, M2; and 6, M3.

FIGURE 7. m1 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.

FIGURE 8. m2 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.

FIGURE 9. m3 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.

FIGURE 10. M1 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.

FIGURE 11. M2 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.

FIGURE 12. M3 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.